Does anyone make a dynamo light buffer battery that will keep it going at full power? I have a nice SP dynamo hub and an old Supernova E3 Triple dyanamo light. However, the dynamo light isn't very bright when I'm starting my ride, as my ride has a long hill at the very start, so I don't go very fast. Then it's a lot of stop and go riding for the rest of my commute with a few more small hills. The standlight kind of sucks until I've been riding on a straight stretch for a while. Looking forward, I would consider buying new gear to help, but I'm not sure what I need (other than just only using battery powered lighting).

Basically, I want my bike to always have lights on while I'm riding through the winter months where I'm commuting both to and from work in the dark, and not loose lighting when I'm stopped or going slow on a climb (where I'm very venerable). Currently, I have to supplement having dynamo lighting with battery powered lights since the dynamo lights cut in and out due to my hilly commute with lots of stop and go urban riding.

Does anyone make an inline power buffer for dynamo based lights to provide (a) Immediate on when you want to start riding and (b) Constant power while stopped? Or are there lights or other equipment that provide this feature (without forcing me to build my own circuit boards and such)

There are standlights, which are essentially supercapacitors combined with LED headlights. They're designed to be charged from the dynamo while riding and give you a few minutes of extra lighting when stopped at a stoplight. However, all the ones I know will self-dissipate after a while, so they're useless for your purposes of starting off the day with full beam strength (unless you want to bike around on the flats for a few minutes charging them).

For full strength lighting at any time, you really need a battery.

I don't know of any commercial battery-charged dynolights. I built my own circuit that takes the AC from the dynamo, rectifies it, uses the DC to charge an 18650 that then powers my LED headlights and taillights (and charges my cellphone). The circuitry is trivial by itself, but you'd have to know enough about soldering small circuitboards and I can't do any customer support, so I haven't shared it.

The reason I built the rig was that I wanted more powerful LED night lighting (10+ watts) than my dynamo could reasonably deliver at one time. So I charge my 18650 by riding during the day; and then at night, I have instant full power.

My assumption is that if you know enough about electronics to solder it, you should know enough to design it. All parts are available from sparkfun in terms of rectification and smoothing, lithium batter charger, battery, switch, LED current limiter, breadboard, and so forth.

So you already have a capacitor based standlight, but want it charged from the beginning of your ride.
You can manually charge it before starting your ride:

Turn off the lights if the standlight charges while the lights are turned off.
Go find the leads where your dynamo connects to the lighting system
Apply 5V DC to it for a few seconds, for example from a USB-Charger or USB battery. You can sacrifice a USB cable for this, cut off the Mini-/Micro USB connector, split the wires and just manually touch them to the appropriate contacts on the bike (at least on mine, those are already exposed). The capacitor should then be charged. Usually those dynamos produce 6V AC, so 5V DC shouldn't damage the system no matter the polarity. "A few seconds" depends on the power source, but a normal phone charger can provide like three times the power of a hub dynamo and capacitors charge pretty much instantly. There might be a bottleneck in the circuitry surrounding the capacitor, but no matter what it shouldn't take long.

Before you try: Do it on your own risk. The lighting system wasn't designed for this any may thus break - but I don't think it's likely for the reasons explained above.

That being said; I used to commute like that, LED lights, hub dynamo and a climb at the start. I never had problems, the lights intensity was reduced during the climb, but seemed bright enough even at very low speeds. So either you want more light than me, or you have some components in your lighting system which are of lower quality/efficiency. You also mention stop and go, so I assume this is in an urban area, where there are likely street lamps. So I would say that it's pretty likely that your lights are good enough already.


Is having your hands "on the hoods" of drop handlebars safe for braking? I've never had a bike with drop handlebars, but may get one for commuting in busy London (likely a single-speed with mechanical disc brakes).
This would mean riding with my hands mostly on the hoods, but it seems like a slightly awkward position to use the brakes from:

Riding on the drops seems to offer better access to the brakes, but is apparently "less stable due to narrower hand position" anyway — so when talking about cycling with cars, vans and busses around, doesn't seem like the best choice either (for a non-professional).

Overall, is that just all in my head, or is there some cause for concern?

Also, is there any reaction speed data compared with flat handlebars, or other such studies, for this?

Personally, I'd be most worried about situations where I need to react quickly, as well as situations that are usual but I need to be consistent in my braking.
Flat handlebars are like second nature to me, would those be safer?

I commute every day in SF with drop bars. It's not an issue for me. You quickly adapt to the hand position, if you bike is set up in a way that is comfortable for you.

The real safety issue you should be worried about, IMHO is not braking itself, but rather the "heads-down" position you can be in on the bike itself. You have to get used to looking around you/behind you for cars, etc. That's why your position/comfort on the bike is so important.

You can also install cross/interrupter levers for a second braking position option, usually at a nominal cost (not sure if this works with your particular breaking system).

"On the hoods" positions has slightly reduced braking from "on the drops" position for two reasons.
Firstly, you cannot grip the brake levers as low as you can from "on the drops" position. Thus, your leverage suffers and the braking force is reduced.
However, this is not the only problem. Even if you could grip the levers as much as you can from the drops, the hoods do not provide adequate support for your hands. You can push your body back using your hands at the typical levels of braking you do from "on the hoods" position. But if you could due to some form of magic brake as quickly as you could from "on the drops" position, you can't necessarily keep your hands in place while pushing your upper body back so that not only the bicycle stops but also that you, the rider, stops.
For someone who weighs far less than me (I weigh over 110 kg without the bicycle, me and my electric bike weigh over 130 kg total), neither of these issues applies. For example if you weigh 70 kg, and have 15 kg non-electric bicycle, you need only 65% of the braking force that I need to stop both you and the bicycle, and you also need only 64% of the support for your hands at the hoods. Both of these are doable.
So, in summary:

For lightweight persons, not an issue to brake from the hoods
For heavyweight persons, you find braking from the drops is more effective

I don't consider the reduced braking from the hoods to be a show-stopper. I like drop bar bicycles far more than I do like flat bar bicycles. I would never ever switch back to a flat bar bicycle for road riding.
Try it, you'll like it!
Also, all three most commonly used hand positions (on the drops, on the hoods, on the corners) allow very quickly accessing the brakes. On the tops does not allow, but then again you won't use it much.


Gears slipping after a chain change I have a Lappierre Zesty 314  (2012). I'm running XT rear mech, an SLX front mech, my crank is XT, rear cassette is XT and XT chain. I went to the Forest of Dean and after the day was over I snapped my chain! I picked up a SRAM chain for my bike and now when I pedal hard it slips with a big bang. I have new Eastern Havens so my hub is fine. Can you help with any ideas to help me solve this? Shall I get a new rear cassette?

Look up the proper chain for the components. XT is not a size - that is the group level.   You should size the chain for the number of speeds (gears).

Inspect the cassette.  As they wear the teeth get sharper spaces get longer.  Visually compare it to a new cassette even if you are looking at a picture.

If your chain snapped then possible something else is damaged.  Inspect all the drive components.

A cassette typically last 2-3 chains.  If you get a new cassette then change the chain.

A worn chain wears a cassette down faster.
And a worn cassette wears a chain down faster.

A chain is cheaper and easier to change so cheaper to stay with a fresh chain.
There are tools to measure chain stretch.
Replace a stretched chain.

A new chain on a worn cassette will jump - basically both the chain and cassette stretch.

Typically you'll want to change your chain and cassette together, since they will both be worn, so it's not surprising that you're experiencing some slipping. It's also possible that your existing cassette is bent or damaged in some way rather than just being worn. I had an old XT 9-speed cassette where I somehow bent a few teeth to the right in the middle range, and even though it was barely noticeable, it made those middle cogs totally useless under load.

I assume you also bought a new chain that's the appropriate width for your rear cassette (9, 10, 11-speed, whatever). So if it's adjusted well and you have the right chain, I think it's safe to say that you'd benefit from also replacing the cassette.


How to carry a trumpet for long trips I'm a trumpet playet and I would like to carry my instrument with me on long trips. I have a quite light bag for my trumpet which can be carried as a backpack, but this might be troublesome for long trips. I would like to somehow attach my trumpet (probably inside of a case) directly to the bike. Currently my bike is equipped with a luggage rack at the bag to which saddlebags are attached.
Any idea is welcomed !

I'd suggest a top-of-rack bag for your instrument, because its more aero when the load is in-line with the rider.  If there's no bag big enough, use a series of bungee cords to securely strap the case to the top of the rack, lengthwise.  Feed a cord under the case's handle too.   If this becomes a regular thing, you can even make a "tray" permanently secured to the top of the rack, exactly the right size for your case, with lips/sides to stop it sliding out.
You could use panniers / saddle bag on the side of your rack, but that tends to stick out into the wind a big more.  There's also the increased risk of damage being stuck out.  But a pair of panniers lets you carry other stuff on the other side, and still use a top rack bag/tray.
Carrying the trumpet on your back is a workable solution too, but it increases the sweatiness of your back, and can exacerbate damage and injury in the event of an accident so its not ideal.
Carrying it inside the frame triangle, or above the top tube is probably not going to fit, and will interfere with your legs while pedalling.
A front rack might be a good idea too - you can see it while riding.
A trumpet is not really large enough to need a trailer, so that can wait until you upsize :-)

Whatever you choose, also consider waterproofness.  Most instrument cases have a velvet / velveteen liner fabric which doesn't like getting wet.  If you have to ride in the rain, consider a "dry sack" large enough to hold the whole case and seal up.   Good for a towel and dry clothes too.  This would also help prevent marking of your case by vibrations against the rack.

And here is the alternative answer.
Yes, I have done this before. I played in the band during high school and sometimes I would ride my bike instead of driving my car way back in the dark ages of the low 80's. The band teacher would let me store my expensive racing bicycle in the band room but one time I forgot that I would need to take trumpet home and ended up holding it with one arm while steering with the other arm. All while wearing cycling shoes and again, an expensive racing bicycle. Yeah, I did end up hitting a car with the expensive trumpet while riding on my expensive racing bicycle. It did help that I hit a car of a friend of mine who was driving a POS car [just like my POS car] and didn't worry about it.
Short story - there are things that a car is made for - this is one of them. You are dealing with one of two different expensive things: an expensive trumpet or a car which is once you configure insurance and the car itself will be expensive.  Take the car.
Ignore the POS bicycles that have baskets, there are times that you just need a car.


lacing Alfine wheel, trailing spokes inside or outside hub flange I am about to lace an Alvine hub wheel. Reading Sheldon Browns article there is a suggestion that the trailing, and so key, spokes might be better laced the opposite of what would be done for a deraillieur wheel. Meaning that the trailing spokes would go on the outside of the flange of the hub, thus the flat end of the spoke is on the inside of the flange.
Is this advisable and correct or does it not really matter? Or have I misunderstood completely.

Thanks for reading.

If I remember correctly Shimano recommends lacing with trailing spoke heads in (flat part out) for rear drive-side whereas Sheldon Brown recommends the opposite, so take the reasoning that sounds best to you and run with it. Ultimately it probably doesn't matter much, especially if your chain doesn't fall off to the inside which it shouldn't if everything is in proper adjustment. I just looked at two sets of wheels that I have built which are nearly identical. On the older set I have drive-side trailing spokes with heads facing out, on the other set they are facing in. I have no recollection of why I made the change. I do not notice a difference and I haven't had problems out of either set. If I were going to build another set right now I would probably do trailing heads facing out, but as Sheldon Brown pointed out:

  Note: This is not an important issue! There is a sizable minority of good wheelbuilders who prefer to go the other way around, and good wheels can be built either way.

I remember Robert Wright’s wheelbuilding guide thinking about a rope over your shoulder pulling a load is easier than facing the load and pulling with your hands. Ie: the hub flange becomes the shoulder and provides another contact point to better direct drive force to the wheel. Big Jim


How do I measure a bottom bracket? I need to replace the bottom bracket bearing on my fixie. I plan to get a Shimano UN26, but I note that there are a number of different sizes. The sizes seem to be expressed as 68-110, where 68 is the shell width and the second number varies according to the table below, from Shimano's tech specs.

I assume the second number relates to the width somehow.

How do I measure my existing bearing? Is it length from end to end of the axle? Given that the only tool I have for this is a ruler (no calipers) what's the best way of measuring my existing bottom bracket to ensure I get the right size?

Update

I removed the bottom bracket and it had "103" stamped on the axle. I also measured and it was exactly 103mm from end to end. So it looks like the measure is the length. I went to my LBS and they assured me a 107mm (coincidently the shortest one they carried) would be fine. I installed it and my chainline is marginally out (I guess by 2mm). So I'm going to try to find a 103mm from somewhere else.

Thanks!

The numbers 113, 115, etc. mean the total axle length in milimeters.

On a singlespeed (fixie, internal-geared-hub), the important measure is how much the right side of the axle "shows out" (not always perfectly symmetric), and how much the crank can "sink" into the tapered square, which may vary from model to model even with the same nominal spindle length, and with how much torque you apply to the bolt when installing.

I have two single-speeds (fixie and IGH), which required some "fine tuning" to get a straight chainline:

One had a 73mm bottombracket tube on the frame, so I had to use a slightly shorter spindle, because it is installed off-center (2.5mm to the right because of extra "frame width" on the right side, the nut on the other side didn't have a lip and could be inserted fully inside the bb thread);
Other was regular 68mm, but two models with same spindle length had different offsets on the crank (because of taper, lip width of the shell, and some other obscure factors) and I had to install a cheaper model (generic instead of Shimano), it was the only one that fitted, and I'd rather have an aligned chain than a slightly better bottombracket.

Typically you will want to replace you bottom bracket with the exact model that is currently in the bike assuming that the one in the bike is the correct BB, or the original. Yes there is the measurements on the BB, 103 for you to be exact, but in order to get the ideal performance a lot of crank sets are designed to go with a specific Bottom Bracket so even though a bottom bracket may fit in your bike, that doesnt mean it will work optimally. If you are looking to dind a bottom bracket that is a higher quality where it wouldn't be the same as whats in your bike your best bet is to take it to a shop


Which threaded headset size do I use? I have a frame that I want to use. It is an old early 80's Cannondale frame. How do I tell what size threaded headset to use? What diameter should the tube be?

If you have the fork in hand, it's easy enough to directly measure the outer diameter of the steerer tube using a set of calipers or a ruler across the top. The common threaded headset size is 1" (25.4mm), but 1 1/8" (28.6mm) is not unheard of.

If you have only the frame and are trying to measure from the inner diameter of the head tube, then you are measuring for the outer diameter of the headset cups. For a 1" headset this should be 30.1mm, for a 1 1/8" headset this should be 33.9mm, give or take at most 0.2mm.

1980's should be too early, but Cannondale also experimented with oversize head tubes at several points - if the fork or frame is larger than that specified for the 1 1/8" size, you'll probably want to look into a different fork, and probably a reducing headset as parts are going to be almost impossible to find.

I have only been able to find a headset that measures 1-5/16" on the small end of the bearing cup that goes into the headtube on the bike. All of the bearing cups I've found is 1-3/4" on the large end and take a large diameter bearing. The headset that I have is a 1-5/16" bearing cup o.d. but the large end of it measure 1-5/8". Where do I find a headset like that?


Reusing SRAM 10 Speed PowerLock? According to: http://www.sram.com/sram/road/technologies/powerlock

"SRAM chain engineers developed PowerLock as a tool free, sure and consistent way to connect our 10 speed chains. While PL does not require special tools for install, the especially tight tolerances of 10 Speed drive trains mandated that each PowerLock is good for a one-time application only."

According to: http://www.competitivecyclist.com/sram-pc-1051-chain

The SRAM PC-1051 Chain is compatible with both SRAM and Shimano 10-speed drivetrains. Please note that while the PowerLock installation can be done tool-free, it's recommended to be used only once due to the extremely close tolerances required by the narrow 10-speed design. So if you must break your chain for maintenance reasons, a new 10-speed PowerLock link will be required to reassemble it.

Two questions:

Why is this the case?
Have people hear observed or seen tests about what happens if you re-use?

I use the Park Tool Master Link Pliers to remove master links. I have a hard time believing that doing it that way stresses it significantly.
Related, from http://www.bikeradar.com/us/mtb/gear/article/trail-tech-mastering-master-links-36757/:

"According to SRAM, the ridge that joins the two plates of the PowerLock together can be damaged when unlocking it, increasing the risk of failure if reused. So yes, if you choose to reuse a PowerLock there is an increased likelihood of if failing, according to SRAM."
I know a number of professional and team mechanics who routinely reuse PowerLocks on their own bikes, but replace them with a new link when dealing with a customer or athlete, so it’s a bit of “do as I say, not as I do.”

It's not so much that reusing the link increases the chance that the pins or plates that the Powerlock is made up of will fail, but rather that it increases the chance that the link will come apart the same way it was put together. Each time you remove that link it wears down the "ridge" that snaps the pins in place on their opposing plates. This increases the chance that the link can undo itself in unusual circumstances. It may also slightly increase the chance of the link failing in the case of shifting under heavy load, which should be avoided anyway.

SRAMs 9 speed quick links were notorious for coming apart on the trail as they are reusable- some of this had to do with improper removal which damaged the relief that held the pins in place. It's probably easier for the company to just say "don't do it" than to say "do it this way" and folks don't adhere to the manufacturer's recommendations, leading to failures.

TL;DR version- if you only remove the link on occasion, its good for the life of the chain. Don't reuse an old quick link on a new chain.

When I used KMC Missing Link, it bent as I changed gears under load. Stupid me! But with SRAM PowerLink, I did same thing, and so far so good. However disconnecting regularly was a real nightmare.  Now I grease pins before assembly and the problem is gone.  I have reused eight to 10 times to rotate chains on 9 speed.  Have started same method on 10 speed, and so far so good.


...why do male cycle commuters outnumber females? I haven't been able to find any usable statistics but from my observation of cycle commuters men appear to out-number women by around 10:1

This is in a relatively bike friendly city, at least by North American standards (Vancouver Canada).  In my office, a downtown mixed office building, there are no women commuters.

There are many more women cycling in road clubs at the weekend and lots of women committed to cycling groups and promoting cycling.

Is there any reason why women don't commute by bike and is there anything that can be done to boost the numbers?

(rephrased to make this a more useful question - rather than a friday afternoon thing)

Oddly the well publicised bike counts down here don't seem to be quite so free with their results.

I did a bit of counting back in 2001 and got about 20% female cyclists. Fewer on major roads, more on bike paths. 1300 cyclists over 3 months in a perimeter count (because the official stats only counted 5 major entry points). Interestingly despite the compulsory helmet law only 74% wore helmets (I didn't count "helmet on handlebars" as wearing a helmet).

In Melbourne there are stats here, the "cycling to work" and "cycling in Melbourne" pdfs. First graph shows approx 25% female, and in the outer suburbs mostly under 20 years old, with a broader peak in the inner suburbs (interestingly, fewer school age kids than the suburbs)

and a second chart showing that as cycling percentage goes up so does the proportion of female cyclists - women are more likely to ride if a lot of men do.

Speculation...  Fear of breaking down.  For most male cyclists, a flat or whatever is no tragedy; you just fix it.   For women, who may not be as mechanically "ept", there is also the worry of being alone and isolated while doing the fix...

I commute from our cheap-parking garage to the station.  It's only about a mile or so... I'm a police officer in full "bike" uniform, so I'm not worried about being harassed or even attacked during my 6 am ride.  Not so with a lot of women, I would imagine.
We see a lot of women riding alone during the day; fitness riders...  No great fear on well-traveled roadways.


I have jetwashed my mountain bike twice... will it cause any damage? I jet washed my bike around 6 months ago and decided to do it again having got it caked in crap! Only for a mate to tell me how daft I was. Will this have damaged my Carrera Vengeance (I know it’s only cheap) but I’m 15 and I worked hard for it so I would hate for me to have caused permanent damage. Have any of you mountain bike gods out there got any advice for me? Thanks.

If you aim the high-pressure water jet at sensitive parts like bearings (BB, wheels, suspension, headset...) the water will get inside, and your bearings will rust and die. High-pressure water jets are also pretty good at filling your cable hoses with water, and getting past the seals on suspensions. So when using high pressure to clean a bike, stay clear of the sensitive bits, keep the nozzle like 2 feet away so it gets mist.

However if you only aim it at the frame and chain, then no problem. High pressure is really good at getting the muck out of a chain, chainring, and cassette, but it also gets the grease out, so everything needs to be lubed afterwards. Just don't aim it up close to anything that contains a ball bearing or a seal.

As a side note, if you don't want stuff to rust... Your chain and cogs are made of steel because steel is very strong and cheap. Stainless steel is weaker, a stainless chain wouldn't last. Steel rusts though, but it needs to be in contact with oxygen to rust. The oil on your chain forms a film which protects it from oxygen (and rusting). After a good MTB ride, your chain and transmission will be full of crap and if you rode in mud, the water will have removed some of the oil. So if you can't clean your bike straight away, a quick spray of oil will protect the transmission against rust. No need to overdo it, just a little bit of oil is enough. When you clean it, this also removes the oil, so spray a little bit of it.

Here's some key things to note:

Rubber bushings (from suspension components)
Rubber seals (From suspension components, SOME hubs, cassettes, cable housing, etc)
Sensitive metal areas (Shock absorber rams, wheel hubs, bottom brackets, headsets, derailleurs, etc)
Lubricated areas (Hubs, bottom brackets, derailleurs, shifters, chains, etc)
Fragile areas (Derailleur springs, shifter springs, etc)

All of these areas are VERY sensitive to high pressure/stress. If you point the pressure washer jet of water perpendicular to these areas, very close and hold it there for a substantial amount of time without moving it constantly, you could potentially do some damage. The best bet is to entirely avoid these areas. Hubs, headsets and bottom brackets contain grease, which the water will blast out of these areas and sit next to the bearings, causing them to rust. Springs inside derailleurs (mostly rear) and on your shifters are usually quite fragile with high pressure water, and these are also commonly covered in a grease.

Any soft materials like seats, rubber/plastic bushings for suspension parts and rubber seals can be cut with a water jet, depending on pressure, proximity to these parts and how long they're held in front of the pressure for. My pressure washer, when I was testing it on an old scrap bike, can cut through the fabric and sponge on my old seat. Having gone horizontal, I could have cut a sheet of seat off my bike if I wanted to. If you have an old, cracked leather seat on your bike, the pressure will destroy it in no time.

Anything that needs to move smoothly and freely, like cabling, will not appreciate the water either. If the water sits on any gear/brake cables for a prolonged period, the water will promote rust in these areas, causing the cables to first become hard to move, stretch and then seize entirely. If you have hydraulic brakes, you need to take even more care; Normal water in a hydraulic braking system is a big, big no-no. Seals on both the caliper and lever end can get severely damaged, causing fluid to leak or water to get in. Not only will it make the braking spongy if it damages it, it 'could' start failing altogether after heavy braking, heating up the caliper.

If you keep the water jet away from the parts mentioned above and try not to focus in one place, you should be okay. As a rule of thumb, keep the jet one to two feet away from the bike, aim at about a 45 degree angle and keep the jet constantly moving. Also, if it's an adjustable jet, set the jet to the fan setting, rather than the pencil-jet setting. Remember to lubricate the chain after, as well as drying the bike down by hand using an old but clean and dry towel that's absorbent. Don't use your best bath towel, use one that you're about to throw out.


Should I go clipless? My bike is a Giant Reign, and I ride in the UK. I like going to local gravity parks and trail centres and my local tracks are mainly downhill orientated but I also like to get out on longer rides. I'm currently running some cheap pedals off an old XC bike and am using skate shoes. When the terrain gets even remotely rough, my feet are all over the place and it's doing my head in.

Obviously I need to invest in some better pedals and shoes, however I'm not sure whether to take the hit and go clipless straight away or to get some decent flats n proper shoes then revisit the clipless question further down the line. Any recommendations?

Clipless makes it hard to bail out when you're in trouble, which is why most DH riders use flats.

A quality pair of flats + decent shoes are going to be just as expensive as clipless pedals and shoes.

Unless you're doing serious downhill (and crashing a good bit), I would go straight to clipless.

It is not that hard to use clipless, you just need to gain muscle memory to how to remove your feet from the pedal. It is takes about 15 min of practice. But as said above there isn't really a point. I didn't find clipless more comfortable or more efficient (they are not) just different. You can do stuff that you can't whit normal pedals. When you are tired you can raise your leg instead of pushing or just focus on not just pushing the pedal as you can make effort along all the pedal travel making it feel like less effort as you are using your both legs at same time.


Bottom bracket needing repacement more often in a single speed bike I used to live in quite a hilly area but managed well with a single speed Mango aluminium bike on most of these hills. I wanted to know if it is possible that due to extra pressure being exerted on the pedals and therefore on the crank and bottom bracket system, the bottom bracket might need replacing more often than a bottom bracket in a bike with multiple gears? I feel like I do damage to my bottom bracket way more quickly than I should. Perhaps the bottom brackets I have had were of low quality? I don't currently know what of bottom bracket I have installed.
In general what factors are involved in the usual degradation of the bottom bracket?

It is inevitable than with more radial load, bearings will have lesser lifespan. The only alleviation to this is to get good quality bearings.
If you notice a decrease in your bearings' lifespan, check if you've fitted your bottom bracket properly and specc'd everything to more or less proper torques indicated. If bearings fail regardless, there may be misalignment either on your bottom bracket unit or the BB shell itself. (more likely the latter)
Due to the larger forces inputted, the misalignment's effect of degradation is aggravated.
@juhist 's option for outboard-bearing bottom brackets only serves as a non-direct solution and masks any genuine issue the drivetrain has.

Bottom brackets have a fundamental flaw that the most typical shell size is too small for a good quality axle and good quality bearings at the same time. All bottom brackets fully inside the shell thus fail very often, usually due to bearings or axle breaking.
Typically, the higher the load is, the more likely is the failure of axle or bearings. So, gearing affects but your weight affects too.
Shimano has outboard bottom brackets in Hollowtech II components. These have the bearings outside of the bottom bracket shell. Thus, with Hollowtech II, you can have both good axle and good bearings.
I think that with Hollowtech II, your bottom bracket worries should be mostly gone. What is left is crank failure. The crank-pedal attachment has a fundamental flaw too, it cannot keep the pedal non-moving. Microscopic motions slowly damage the pedal eye of the crank, to result in a fracture of the crank. The pedal eye design should be modified to have a countersink and the pedal spindle should be modified to fit to the countersink. With traditional pedals, the crank can be modified by adding the countersink in a machine shop and a split collet can be made to fit to the pedal spindles: http://pardo.net/bike/pic/fail-001/FAIL-016.html
The countersink and manufacture of the split collet is probably more work that you are willing to do, so eventually your crank fails -- especially in a single speed bike, if you are a heavyweight rider. If the bottom bracket is of the Hollowtech II style, it will probably outlast your cranks.
You might be interested in this online museum of broken bicycle parts: http://pardo.net/bike/pic/fail-001/000.html

Perhaps the bottom brackets I have had were of low quality?

Were they of the square taper type? If so, they are low quality by design. Toss those away and select Hollowtech II.

In general what factors are involved in the usual degradation of the bottom bracket?

Engineering (type of your bottom bracket)
Price (affecting the quality of bottom bracket materials available for the price point)
Your weight
Gearing
Your riding style, spinning at high speed versus mashing at low speed
Tire size and air pressure (affecting suspension characteristics)
The non-uniformities of the road
Whether you approach non-uniformities of the road sitting on the saddle or standing on the pedals
Whether or not you ride in a hilly / mountainous area
Whether or not you use drop bars from which you can pull up using considerable force allowing you to pedal with more force
Whether or not you use clipless pedals allowing you to push up using the rear foot to result in more force at the front foot.


How can I fit 6 bikes on a hitch rack? How can I fit 6 bikes on a hitch rack for my Toyota Sienna van?  Thank you!

Here's a rack that will do six. I have no personal experience with this one and the fact that neither of the top two rack companies (Thule and Yakima) do a six bike rack makes me think you should approach with caution.

[Link removed due to the old link being expired/stale. The link was to a "Northshore 6 Bike Rack"]

I have seen, with mixed success, 4-bike bike racks where folks have strapped an additional bike into the mix. Again, proceed with caution.

www.draytonsolutions.com Here is one that will carry eight (8).


Understanding how to calculate critical power curves Hello fellow cyclists,

There are services out there that can calculate power curves based on your bike ride (when training with a power meter).

This curve shows the time to exhaustion (t) based on the power P. So let's assume that my maximum power is 1000 Watts, then this formula will. calculate how long it would take to be totally exhausted (probably not that long for me).

The formula I keep seeing is this: P(t) = W’/t + CP

This formula looks extremely easy and yet I have trouble understanding what those values are. Are there any calculation examples out there?
If I understand this correctly, CP is the critical power. This is the power that can be sustained (theoretically) infinitely. I have to provide this value, so let's just assume this is 200 Watts.

What is W'? According to the internet, this is the work capacity that is currently available. How can I calculate this?

Are there any example calculations?

Example activity (not real numbers, just for an example calculation):

Duration 1h, 3600 seconds

FTP = 200 Watts

CP = 160 Watts

Power During Ride: 3600 data points, every even data point is 150 Watts and every odd one is 120 Watts.

I also now that there are way more complicated formulas out there, but I would like to understand this simpler one first.

TL;DR: What is W' and how can I calculate it based on my bike ride.

Any help is appreciated.

There are a couple of different versions of the CP model. You are looking at the earliest, simplest, two-parameter model proposed by Monod and Scherrer in 1965. While there have been modifications and expansions of the original model since then, the basic simple model has enough features that you can understand it. Although CP has been described as "the power that could be sustained indefinitely," in practice it works fairly well from durations of perhaps 3 minutes out to around half an hour -- additional parameters have been proposed to address durations before and after that.

If you have been riding with a power meter for a while you've undoubtedly seen a curve as you described, showing maximal average power in watts over durations in time. The simplest way to understand the Monod-Scherrer model is to notice that a watt is a Joule per second. So, to get Joules of work, multiply the power in watts by a duration in seconds. Monod and Scherrer noticed that if you plot Joules on the y-axis and time in seconds on the x-axis, the relationship is nearly linear for durations from around 3 minutes out to around half an hour. A linear relationship like that can be approximated by a line with an intercept and a slope. The slope is what they called CP, and the intercept is what we now call W'.

If Joules(t) = W' + cp*t, then an equivalent formulation is the one you've already seen. Since a watt is just a Joule per second, just divide the equation by time on both sides to get watts(t) = W'/t + cp. In this formulation, if you plot watts against time, CP will be the asymptote and W' will be a constant that determines a hyperbola. You can see why some people prefer the intercept and slope formulation rather than the asymptote and hyperbola formulation.

Note that because W' is the y-intercept, it describes an amount of energy in Joules; because CP is a slope in the regression of Joules on seconds, it describes power in watts. Thus, if CP were 200 watts and W' were 15000 Joules (= 15 kilojoules), then a prediction for the amount of work you could do in 600 seconds (= 10 minutes) would be 15000 + 200 * 600 = 13500 Joules over 600 seconds, or an average of 13500/600 = 225 watts. You can think of W' as a "stock" of energy (like a storage battery) that you can expend in addition to the steady state power you can sustainably produce (that is, CP). You can expend that W' quickly or slowly but once the battery is run down you have to recharge it. In this example, you were expending it over 600 seconds, so another way to think of it is this: if your CP were 200 watts and you have 15000 Joules of stored energy, your baseline is 200 watts and you can add to that 15000/600 = 25 watts for a total of 225. If you expended it over 300 seconds (= 5 minutes) your baseline is still 200 but you can add to that 15000/300 = 50 watts, so your predicted maximum power for 5 minutes would be 250 watts. This alternative way of calculating predicted maximum power is Watts(t) = W'/t + cp.

In either formulation, if you have values for W' and CP, you can calculate the estimated power for any duration from around 30 seconds up to around an hour. (If you use the Joules formulation, you just have to divide by the duration to get watts). That's how the CP curves that you've seen are calculated: using values for W' and CP, you can create a curve and plot it showing predicted power at any duration. Note that with only two parameters, the model implies a power duration curve that has an asymptote not only at CP, but also one with the y-axis at zero duration. This is why models with more parameters have been developed -- to deal with the asymptote at zero and the asymptote at long durations.

From a practical perspective, typically your curve of time to exhaustion will not be "smooth" if you base it on just a single ride -- usually, you combine the maximal durations for several rides over a few days or weeks. Also, to get reliable estimates of W' and CP you'll want to make sure you've put out maximal efforts. A typical procedure may be to do maximal efforts at, say, 3 minutes, somewhere in the range of 5 to 8 minutes, and perhaps somewhere in the range of 15 to 20 minutes. That will give you 3 data points. You want these efforts to be maximal for the targeted duration, and typically that means you want them to be relatively steady -- there will always be some variability in your efforts but you don't want the efforts to be repeated sprints of 30 seconds followed by 30 seconds of recovery. Aim for the maximal output you can sustain. I don't recommend that you do these 3 efforts in one ride or even over 3 consecutive days -- space them out over a few days.

That procedure will give you 3 data points of maximal power and durations. Convert to Joules, and calculate the regression slope and intercept. A side effect of this is that you will have the usual regression diagnostics, with standard errors for the slope and intercept and an R^2 so you can evaluate goodness-of-fit. If you do more tests, you can use more than 3 data points for your regression.

You can watch Marks videos here that will explain W' vs CP in detail, he has a few different videos here but this is one https://vimeo.com/283303558


Edit gps recorded track I'm using Garmin Fit for my phone. On a long ride my phone went out of power and didn't manage to record the last of the track. I've uploaded the first part of the ride to Garmin Connect and can export the ride to gpx.

My question is
Please help me find a online-service that allows me to:

Manually edit and finish my route using an editor with "stick to road" functionality

Set the time for the new points, so I will get an average speed for the last part of the ride and the total time will be correct (I know that one).

Export the result to gpx or another convertable format, to upload to Garmin Connect.

Interesting question. I don't know if there is a better way but I can offer a couple of suggestions.

There's a thread over on BikeRadar where someone is wanting to stitch two FIT files together, there's a suggestion to convert to TCX then manually merge the files using a text editor.

http://training.bikeradar.com/forum/longest-day-road-challenge-324/combining-separate-garmin-files-into-single-ride-152481

The posts within the thread indicate that the suggested method works.

Your case is obviously more complicated since you only have the one FIT file to start with.

So, you can manually create an activity to represent the last chunk of your ride. Garmin Connect supports this, although I don't know how functional it is. I do know that Garmin Connect will allow you to export your activity as a TCX, as I have done this. I can also suggest the site rideWithGPS, which is my preferred portal. RWGPS will allow you to manually create an activity (including drawing the route on a Google map, let you to enter start/total times, and then export it (as TCX History).

You need to register with RWGPS but I don't think you need the pay account to do anything I've suggested.

Whichever way you choose, by the end of this process you should have two TCX files that you can merge.

In passing, GPSies.com is a great site for format-to-format conversions, although in your case you'll get your resulting TCX into Garmin Connect no problem.

One thing I would ask is that you let us know how you get on - I've never needed to do this but I'm a big Garmin user and there may come a day when I'll want to know this myself

Good luck!

GPX Editor seems like it should meet your needs.


Cantilever brakes gets very weak if it rains I have a bicycle with cantilever brakes.

Under light rain or dry weather the braking action is not very powerful, but good enough.

However, under heavy rain the braking action gets close to 0.
This become especially problematic if I carry luggage or am going downhill (it can take > 100m to stop under theses conditions).

What can I do to improve this?

Note: the pads are a bit worn out and I will replace them soon, this is however not the source of my problem (encountered it while they was new/ well adjusted)

Edit:

Finally I got a heavy rain and could test out the proposed solutions.
I fixed the brake angle on both front and back wheel.
I changed only front brakes pas with newer ones (thicker, bigger water drain, but shorter ones).

Yoke angle did yield a noticeable improvement on the braking action, wether wet or dry
Changing the pads yielded the a huge difference in braking action under wet weather only (wear was not a factor here)

Conclusion: Both technique should be used together. Choosing an appropriate pad is VERY important.

I think your transverse cable has got too great of an angle, and you can adjust it to provide more powerful braking force.

Much of the mechanical advantage of cantilever brakes comes from the "yoke angle", the angle the transverse cable makes from the horizontal. Sheldon Brown explains this in detail on his page about cantilever geometry (it's actually more complicated than Sheldon's explanation, but it's a good approximation)

(based off cantilever brake image from Shimano)

A transverse cable that pulls vertically upwards would have no additional  mechanical advantage, so would have a mechanical advantage of "1" while a transverse cable that is completely horizontal would have in infinite mechanical advantage (it's impossible to have a completely horizontal cable since once you apply the brakes, the cable will deviate). The mechanical advantage is 1/sin(yoke angle) and he provides a handy chart:

Yoke Angle
(Degrees) Mechanical
Advantage
90°   1
80°   1.015
70°   1.063
60°   1.15
50°   1.31
40°   1.55
30°   2
20°   2.92
10°   5.76
5°    11.47
0°    Infinity!

It's hard to tell exactly what your angle is in that picture, but it looks like it's close to 60 degrees, so you're not getting much mechanical advantage from the yoke angle.

If you can decrease this angle either by shortening the tranverse cable, or by widening the cantilever arms by sliding the brake shoes closer to the rim (which would help "flatten" the transverse cable, decreasing the yoke angle), you can gain significantly more mechanical advantage. You don't want just go for the greatest amount of mechanical advantage since you'll run out of available cable travel if it's too high, but you can definitely tune the brakes for greater mechanical advantage.

There are additional cantilever adjustment tips on Shelden Brown's cantilever adjustment page.

Just an idea here, but have you tried to see if you could put V Brakes on to your bike? Even if it's just the front, that would still improve your stopping power. I used to have cantilever brakes on one of my bikes a long time ago and when I went to V Brakes it was so much better. Cantilever brakes aren't all that good at giving you stopping power. Perhaps if you can change over to V brakes I think you will see an improvement.
I hope this idea helps.
cheers


Garmin 510 lost data I rode the Georgia 3 gap bike ride yesterday.  For me almost a lifetime accomplishment.  I used a Garmin 510 and when it reached 22% I plugged in an external charger.  The screen continued to indicate my ride.  However, when I finished and hit Save  there was no data preserved.  Is there any way to retrieve this data?

Thanks, Dave Holmes

I have seen similar happen with my Garmin 500, regardless of duration/distance of the ride. For me, it occured when I had the Garmin plugged in to my Mac. I would delete activities from the Garmin and then safely remove (will also happen if you unsafely remove) the device. How to avoid this on Mac operating systems:

Delete your activities on Garmin
Empty trash via finder menu
Safely remove your Garmin device

I haven't tested if similar occurs on Windows or Linux.


Mechanic says not to use top three/bottom two gears or the chain will throw I just bought a BTwin Fit 5, all stock, fresh from the distributor, Decathlon. Took it for light pacing at the store and things seemed OK. About 100 metres out the door, I shift up to the top end of the range, pedalling firmly but not hard, and it promptly throws the chain to the outside.

Returning to the store, the mechanic puts the chain back on, adjusts the tension on the derailleurs and tells me not to use the top three or bottom two gears (i.e., the 3 highest resistance and two lowest resistance shift positions in the drive train's range), or the chain will throw again. I asked why, but unfortunately, I'm a foreigner and don't speak the local language well enough to understand any of his explanation. Please note I definitely did not misunderstand the bit about not using the gears; this was crystal clear.

Wild speculations on what he may have said about the reasons for this:

Chain tension or play due to the lateral shift between the inner and outer gears of the front and rear cassettes when shifting
Chain length
Something about the derailleurs

Again, there's a substantial language barrier and I have zero confidence in my understanding of what he said about why I shouldn't use those gears.

If you're not familiar with Decathlon, it's a sports department/box/super store. Definitely not a high end or dedicated bike shop. The house mechanic struck me as less than an expert, to put it gently. I've definitely read some reviews online griping about the inability of Decathlon staff to correctly set up the drive trains of new bikes. However, it's important to understand that this quality of expertise is representative of (or better than) that of every shop within an hour's travel.

This advice seems utterly mad to me. What on earth could be the reasoning behind this? What can I do about it? Aside from the obvious of taking it to a better mechanic, as that presents substantial difficulty for me on a number of fronts. The bike shifts without a problem, including before the throw. I did test out every gear during my test ride. I haven't yet experimented with trying to reproduce the problem yet; I'll do so in the next few days most likely.

The bike has a Shimano Sora groupset and Shimano Deore shifters. I'm an experienced rider but no mechanic; I haven't done anything beyond basic maintenance myself. I can provide additional pictures and am game to make relatively minor adjustments, but even just clearly nailing down the issue would be considerably useful.

Additional pictures, shifted to big-big.

You have a double front, right? The usual advice is to not shift into the highest 3 gears in the rear cassette when in front the chain is on the large chainring, and to not shift into the smallest 3 cogs, when the chain in front is on the small chainring.

This prevents cross-chaining, which wears the chain quickly, produces noise and difficult shifting. Furthermore, some derailleurs may not even support those extreme combinations, when the chain is crossed.

On a side note, the chain should not be dropping in any gear combination, probably the limit screws should be touched a bit, as linac describes.

What your mechanic said, is true for most drivetrains.

And there's absolutely no point in using extreme combinations, such as 1:8 or 3:1, as they are doubled by 2:somethings (first number meaning the front gear, second for rear gear).
All you need is all 2:x plus probably no more than 1:1, 1:2, 3:7 and 3:8.

Here's a ratio calculation I made for a 11-32 rear and 24-42 front cogsets. Colors depict identical or nearly identical ratios (red borders mark "forbidden" combinations"):


How to properly ride over ripples on gravel roads (washboards)? On certain back-country gravel roads, a combination of erosion and tire-tread seems to create these 4-inch ripples that can repeat for long stretches of the road. Riding over them at any speed at all creates a horrible vibration that is, to say the least, extremely uncomfortable.

However, not only is it extremely uncomfortable for me as a rider to be jostled around in that manner, it also can't be good for the safety of my bike.

Is there a proper way to go over these annoying ripples without damaging either me or my bike?

stand on pedals
knees bent (not straight) keeping your butt 10-20cm from the seat
your hands should be very relaxed on the handlebars (your body should be supported 95% with feet and just 5% with hands)
keep your back straight (do not hunchback)
look ahead
enjoy

This works on all bicycles.

sketch from http://www.amazon.com/Mastering-Mountain-Bike-Skills-Edition/dp/0736083715

Larger tires and lower pressure will help a bit, staying out of the sake is good for your bum.

Other than that, your going to have to grin and bear it.


Is cycling in the Netherlands without a helmet safer than cycling with a helmet in the USA? We moved to Netherlands and no one seems to wear a helmet. My teenage child did have a helmet but said she lost it. When my wife wanted buy her a new helmet, my daughter said she will refuse to wear it. This ended up in some family drama between them.

My daughter ended up saying that it is safer to cycle without a helmet in the Netherlands, then with a helmet in USA. To end the crisis, we agreed that she does not have to wear a helmet if this is true. (My wife expects it to be false) But I am not sure, as I read once that the safety of a helmet is generally overestimated (and there is also some risk-compensation). Hence my question is:

Is it true that cycling in the Netherlands without a helmet is safer, then cycling with a helmet in the USA?

Apart from that my daughter claimed that the health befits of cycling outweigh the risk by far. Is this true?

Please give scientific evidence if possible.

There's a simple answer to the question you didn't actually ask: in the Netherlands cyclists who wear helmets are much more likely to be hospitalised than those who don't

Although the Netherlands is probably the safest country in the world for cycling, helmet wearing among Dutch cyclists is rare. It has been estimated that only about 0.5 percent of cyclists in the Netherlands are helmeted.
However, according to Dutch Government data (Rijkswaterstaat, 2008), 13.3 percent of cyclists admitted to hospital were wearing helmets when they were injured. Why does wearing a helmet appear to increase the risk of being injured so substantially?
The answer is probably related to another statistic. Of the injured cyclists wearing helmets, 50 percent were riding mountain bikes and 46 percent were riding racing bikes (Rijkswaterstaat, 2008). In other words, most helmeted cyclists in the Netherlands are engaged in a competitive activity, with very few making utility trips on the traditional style of Dutch bicycle.

I can't find a useful answer because of that. I couldn't find statistics that answer "of the less than 1% of utility cyclists who wear helmets, how many were killed or injured"?
Of course, having so many people riding bikes on the roads also means that of the people killed on the roads, a high proportion are cyclists (about one third). The Netherlands is also the safest place in Europe to use the roads (45 deaths/million pop, cf 145 in Greece which is the worst in Europe and 147 in the USA).
What that means is that in The Netherlands about 185 cyclists die every year compared to 700-odd in the USA (~4x as many, thanks whatsisname). There are more than twenty times as many people in the USA... but more trips by bicycle in the Netherlands. You're still safer there than any inhabited part of the USA. You're safer on a bike in The Netherlands than in a car in the USA, even just looking at immediate crash danger rather than life expectancy (the lifetime risk of death remains 100%, obviously).
There are some amusing results of that:

After a recent decline in the murder rate, you are now fractionally more likely to die while biking than to be murdered in the Netherlands!

In Amsterdam, you're still more likely to be murdered, though.

You're also more likely to die by murder in the U.S. as a whole than by biking in the Netherlands.

You are also more likely to drown here than either die biking or be murdered, especially if you are a child.

My suggestion is to look at it the other way: if you-the-parents insist that your daughter wear a helmet while cycling, will she keep cycling? Will she be unhappy that her mother would prefer her be socially ostracised than even try to fit into the new culture? Will she just observe that her parents are failing to assimilate and reject them, rather than everyone she knows?
Also try flipping it - how would your wife deal with someone who moved to rural USA and didn't want their daughter to learn to drive? Or insisted that she only travel in the Smart car, since that's the safest small car and it's what her parents had back home in the Netherlands?

Is it true that cycling in the Netherlands without a helmet is safer, then cycling with a helmet in the USA?

Most likely it is, given the status of cycling in those countries and the ridiculously weak helmet standards.
Cycling has safety in numbers: the more cyclists there are, the safer every one of them is. Netherlands has a lot of cyclists.
Also the risk of cycling one kilometer is about the same as the risk of walking one kilometer as a pedestrian. If you consider a country dominated by the automobile, to get anywhere from the suburban area you have to ride a huge distance. If you consider a country dominated by cycling, the distances to get to places of interest are probably much shorter. Thus, I assume a random trip in Netherlands is probably much shorter than a random trip in USA.
The additional risk of cycling compared to risk of walking comes from the possibility to cycle far longer distances than it is reasonable to walk.
It is not a surprise that cycling is not more dangerous than walking is. Both are means of transport where the head is at about the same height and there's a danger of falling.
About the head height: helmet tests are done with a severed head. If we consider a cyclist or pedestrian, the head is at about 1.8 meter height. However, when falling, relatively more energy is in the head which moves fastest than your toes have. The toes when falling won't move much, but the head is moving at a great speed. Thus, falling is not comparable to dropping a severed head at 1.8 meter height. When considering the physics of a falling cyclist, it can be modeled as a rod 1.8 meters long rotating about one end. Solving the equations, one finds that the head of the rod hits the ground with as much speed it would have if a severed head was dropped from 1.5 times its height, i.e. 2.7 meter height instead of 1.8 meter height.
So, we can establish that a good helmet test drops a severed head from 2.7 meters height. Let's take a look at the helmet tests:

The EU test (EN 1078) drops a severed head from 1.5 meter height
The USA test (CPSC) drops a severed head from 2.0 meter height
The best test (Snell) drops a severed head from 2.2 meter height

Not a single test drops a severed head from 2.7 meter height.
A cyclist on the road faces two threats:

The cyclist's head can hit an oncoming motor vehicle. The speed of this impact is so large that no helmet can protect from it.
The cyclist can fall and the head can impact pavement. This is the impact that has the same energy as a severed head dropped from 2.7 meter height. The existing helmet standards are inadequate for protecting against this.

Based on this, we can expect that helmets do not do much to improve the safety of cyclist. The difficulty of assessing whether helmets prevent head injuries is that severe head injuries are so rare that the only reasonable form of test is a whole-population test where a mandatory helmet law is suddenly enacted and enforced, so that the rate of helmet wearing suddenly goes from negligible to significant. Then we need some measure of severe injuries. As any measure of "severe head injury" is very hard to define, the easiest measure is to count the number of cyclists dead resulting from accidents and assume that the rate of severe head injury is proportional to this.
Such a mandatory helmet law has been at least enacted and enforced in New Zealand. By looking at the statistics, one can see that it can be the case helmets reduced fatalities. However, the argument is more against helmet laws than for helmets, because of two reasons:

The reduction of fatalities is nowhere comparable to the reduction of fatalities due to for example car seatbelts. Often times, a helmet is compared to car seatbelts, claiming that both are very effective safety devices. This is false: only one of them is a very effective safety device.

Due to the mandatory helmet laws, cycling decreased so it is possible that the fatalities divided by number of active cyclists actually stayed the same.

It is a good question whether a helmet could be made that bicyclists are willing to wear and that at the same time is good enough to be an effective safety device. Bicyclists need ventilation unlike motorcyclists that produce their power in an internal combustion engine. Bicyclists are limited in power so aerodynamics and light weight are important. Thus, bicycle helmet must be lightweight, aerodynamic and keep the cyclist's head cool. These design features are at odds with the safety features of a helmet.
In addition to these whole-population tests for which we can thank New Zealand at least, there are scientific studies where cyclists seeking healthcare services are assessed for head injuries. The problem is that to get a large enough sample size for head injuries, the term "head injury" must be defined such that a simple bleeding wound in the head is a head injury. (Then the result is obviously that helmets protect against head injuries if a "head injury" is a bleeding wound.) Also, there is fundamental flaw in this test that the cyclists more worried for their safety (and thus wear a helmet) visit healthcare due to even minor suspicions, whereas the cyclists that aren't worried for their safety (and thus won't wear a helmet) visit healthcare only if they truly have a serious head injury. (Then the result is obviously that helmets appear to protect against head injuries but that result was only due to a flawed scientific study.)


BMX gearing - for road / commuting I have a 2010 Haro Pro Race, which I bought for commuting and general tomfoolery.

I commute on it 2 miles a day, and I want to be able to go faster by changing the current single-speed gearing ratio.

It currently has no modifications from the standard gearing:

Crankset: 3-pc Alloy 175mm, Euro Sealed Bearing BB
Gearing: 39/14

I find that I can go quite fast with this gearing ratio, but when it comes to going down hill it is just too easy and I no longer get any drive.

Can someone suggest a better gear ratio / crankset that is more aimed for top speed, rather than acceleration, yet still allow me to accelerate from a standstill quite quickly?

what spacing is the is the rear hub? I bought an s2c recently to commute on my track bike, two speed internal geared hub with a gain of 38% but it might be over kill for yourself.

Given your setup you have a gearing of about 55inches, if you were to switch out the rear cog to a 12 tooth you would gain 5inches, bring you to around 60 which is considered a fairly spinny ratio on a track bike.

Easiest way is to switch is the back free wheel. However it seems the lowest freewheel available is 13 tooth so you are limited. You could get a new chainring up front which would achieve the same but may need to buy a new chain too.

47 front and 8 rearBut you have to have a minimum of a 175 crank and no killer hills, Plus a lot of gumption you might have to add a link or two I’ll take a link or two away from your chain and you absolutely are going to be boogieing Along with the road bikes assuming you keep high pressure low tread tires and some caffeine on hand. That’s how you get in shape, that’s how you have to be, rock steady ready to go to keep from having to buy a stupid derailed chain bike.  But the initial takeoff is going to be super slow so a huge crank 175 minimum I’m still looking for 190 mm and I believe that should work out assuming again you don’t live in Seattle. So remember when you see me coming on the bike don’t pull out with your car in front of me or you’re gonna end up having road rage trying to chase me down and pass me back. And also keep in mind that the guy that rides a bike like this probably has pretty killer quads, so before you go to start a fight with him Consider this, I’m sure if he wanted to, he could stomp a mud hole straight through to China, L8r Dudes!


How hot / humid does it have to be for cycle touring to become unenjoyable? This November, if restrictions loosen enough to allow it, I am planning on going on a month-long cycling trip from New South Wales to Queensland. That would mean I would be going deeper into the humid parts of Australia as summer picks up. Climate data says the average temperature at this time is a daily average of 28C at 56% humidity. How tough would that be for cycling all day in, assuming maximum precautions are taken with clothing, sunscreen etc.?

I was out in 28C and 50% RH yesterday, not touring, but comparable: a century (160km) at a fast touring pace, laden by the standards of a day ride, and with a brief swim break in the afternoon.  It was hard work (much harder than it would be 10 degrees cooler), but still enjoyable.  You have to plan on being able to obtain water. I got through about 4 litres, and have reached 9 litres in the past on hot 200km rides.  Especially for multi-day riding, like touring, will your appetite survive the heat? I tend not to eat enough on a long day's ride, if it's over about 25C by lunchtime, though if you can buy ice cream...
Road conditions matter - dropping into a wooded valley from an exposed hillside is a great relief.  How likely is shade?
If you can avoid the hottest part of the day, that helps, but many areas lose heat slowly, so avoiding the heat means doing most of your riding in the morning, resting or sightseeing in the afternoon, and maybe doing a little in the evening.  But does this fit with your target daily distance?  Is there a shady (and pleasant, with food/water) place to rest out the heat?
Clothing is tricky.  Clothing for sun protection keeps the wind off, so even if it didn't make you hotter standing still, it would going along.  Arranging clothing to allow more airflow means it flaps in the wind and makes you work harder.
Guessing at your route as Sydney->Brisbane (but not along the coast), and quickly checking the map, the road passes through plenty of towns, so places to stop even if most are small, however street view suggests you'd be riding in unbroken sun for long periods - I've been known to stop and drink under every rare tree in that case.

This is a very subjective question, but I believe there is at least an upper bounds on the temperature most people can tolerate while cycling for long distances. Somewhere a little higher than 37C is where the wind stops cooling you and starts to heat you while you are dry. I've found that if you are cycling at times like that, you need to cool off regularly with some cold water, splash some on your body if the air is dry, or take a break.


What pressure should I run? Front versus the back wheel? I assume it is common sense you should run a lower pressure in the front wheel versus the back. I weigh 175 lbs (79kg), I have tires with max 120 PSI (8.3 bar), what PSI should I run in the front and the back tire on my road bike? I use a 700x25 tire (25-622 ISO/ETRTO).

It depends on the terrain you ride on, what you find comfortable and so on, so you need to play with tire pressures to figure out what fits you. Several companies (e.g. Schwalbe) give recommendations, but they're only good to start -- you need to play with tire pressures to find whats good for you.

The number written on the sidewall of the tire is generally useless. For most riders, a correct pressure is significantly lower than whats written on the tire sidewall, and the tire sidewall rating does not take into account the strength of the rim (wheel) you're running, so blindly obeying it can be hazardous since the rim may take damage if you hit a bump at max pressure. A correctly inflated tire absorbs road hazards appropriately and avoids pinch flats while not having too much rolling resistance.

That being said, a rule of thumb is that the rear tire is about 10% higher pressure than the front tire. But you're completely free to ignore this and find something that's comfortable for you.

For 700C x 25 I run 100R and 90F.
For 700C x 28 I run 90R and 80F.
I weigh 85Kilos and as an endurance rider, ride exclusively on Tarmac (good and bad)


4 punctures in one week, even after replacing tube and tire, what's happening? I've just had my 4th puncture in 8 days on the bike I use to commute to work. Same back wheel each time. I haven't had a puncture before in the 2 years I've had this bike.

After the first puncture I replaced the tube.
After the second puncture I repaired the tube.
After the third puncture I replaced the tube and got a new tire.
Two days later it's punctured again.

What's strange is that the punctures - tiny, like a thin needle - have all been on the part of the tube facing the tire. They have all been randomly spread around the tube with respect  to the valve. Both these seem to indicate it has nothing to do with the rim, and yet with a new tire it's still punctured...?

Any thoughts?

(I'm considering the possibility that someone is sabataging my bike while it's parked in my university parking, though there is evidence against this also.)

The answer to my question -- why did my bike puncture four times, even after replacing the tube and tire -- turned out to be: bad luck.

The first three punctures were caused by some damage in the tire (the punctures on the tube were all on the tire side). After I replaced the tire, I got another puncture - but this time the puncture was on the part of the tube facing the rim. On inspection I was that my rim tape was protruding up at the point of the puncture. Because I had a new tire and tube I had pumped the wheel up more than usual, which perhaps meant that rim tape protrusion was now a problem.

So, four punctures in one week: three from the tire, one from the rim.

For anyone else experiencing a confusing series of punctures, consider that you may be unlucky and that there are multiple problems in your wheel!

This happens all the time; no punctures for months and then all of a sudden I'll get a load of them in a row. One morning I replaced my tube before heading to work after discovering the valve had failed - then halfway to work I got an actual puncture.
I also seem completely unable to properly fix a tube at the roadside - If I fix them at home it's a permanent repair but when I do it out and about I'll have the tire off again before I get where I'm going.
It's just sod's law.


What are the negative consequences of not bedding in disc brakes? It's common knowledge that disc brakes need to be bedded in. But I've never heard or found a description of what happens if you don't bed them in.

Given the number of BSO's that now have disc brakes, and the likelihood that 99% of those never get bedded in, I'm guessing that the consequences can't be too incredibly dire.

But what are those consequences? Reduced braking power? Uneven braking power? Squealing brakes? Reduced lifespan of pads and/or rotors? Are those consequences long term? Or do the brakes "naturally" bed in with regular use and the consequences are only short term?

I think your last comment is the operative point - it will happen anyway sooner or later.

The technology here is basically the same as with automobiles. You start off with new pads and a clean rotor. The bedding in process involves the deposit a small layer of pad onto the rotor (mixed in with a little frictional heat).

Until you have that layer on the rotor, braking could be less powerful and uneven.

You don't ask this, but for completeness, the rotor should be cleaned whenever the pads are changed, using isopropyl alcohol. And, once the rotor is clean, the bedding-in process will start over.

You don't see an awful lot on this subject if you look on the web at bike pages, but as I say if you start looking in the context of cars, there's lots out there and it is definitely not new technology.

Take SRAM for example

  All new brake pads and rotors should be put through a wear-in process
  called ‘bed-in’. The bed-in procedure, which should be performed prior
  to your first ride, ensures the most consistent and powerful braking
  feel along with the quietest braking in most riding conditions. The
  bed-in process heats up the brake pads and rotors which deposits an
  even layer of brake pad material (transfer layer) to the braking
  surface of the rotor. It is this transfer layer that optimizes braking
  performance.

They clearly express the benefits:
consistent and powerful braking feel along with the quietest braking in most riding conditions

If normal riding achieved that SRAM would not have a specific procedure.  For one they warn not to lock up the brakes.

If you deposit an uneven layer I would suspect the consequences to be permanent.

I don't get your logic on if BSO does not do it then it cannot be dire. I don't want my bike to perform like a BSO.

Service Manual
Bed In Procedure


Where can I find a bulb for my vintage 70's generator light? I currently own a 60's/70's vintage light for my bike. I have it attached to my Trek 820 series 26" mountain bike at the moment.

The light worked perfectly fine until one day when I broke the bulb inside. The bulb was marked on the side being 2.5v, even though I know for a fact that the generator on the back wheel puts out about 6 volts.

I have tried several bulbs from Radioshack, and none work or are as bright as the previous bulb inside my Reynold's light. Is there anyplace on the web where I can Find such a replacement bulb? Are there any stores that mint have what I'm looking for? I tried Home Depot also, no luck there...

Thanks in advance!

This is nothing more than a standard dynamo front bulb - 6V 2.4W is what you really need (the rear is 6V 0.6W). Most Northern European bike shops carry screw-in Halogen versions of them for 'Union' brand headlamps of your vintage:

If you are not running the rear light from the dynamo then you need a 6V 3.0W bulb in the front. (2.4W + 0.6W = 3.0W).

The problem with the simple two-bulbs-in-parallel circuit is that if you remove one light (e.g. a broken wire) then too much current goes through the remaining bulb and it blows.

Think about it, go to the bike shop when you have a problem with the bike, not the electronics store or the car-parts store or the aromatherapy store. The staff in the bike shop do know a thing or two, they have heard of bicycles running dynamos and, even if they don't have spare dynamo bulbs to hand, they do have a supplier that they can get them from for you in a reasonable period of time for a price that will not cover their time dealing with your enquiry.

I suggest you visit the LBS first, they may only be able to get you the 2.4W version, if they can get you the 3.0W version then get it and a flashing light for the back. In that way you will have a rear light that works when you stop, more light up front and less likelihood of blowing the bulb (because there is no rear bulb to blow).

Alternatively, get a new front headlamp unit for the dynamo, these may be special order from the bike shop, however, such a unit will have niceties such as a better reflector and lighter construction.

I strongly suggest you have a look at the "REFLECTOLITE" range of lighting supplies. They have bulbs for every type of light - including dynamo lighting. You'll be wasting your time and money going to motor factors. Cycle shops may be able to help but Reflectolite are the best bet - give them a try, you won't regret it.


What is the potential danger of riding bicycle with cracked chainstay and how to fix it? I got a bicycle that has this big tear in the chainstay.

Is it safe for city riding? What is the potential danger?

What could someone have done to cause this kind of damage?

Most importantly what is a good procedure and material to use to fix it?

Thanks

The frame isn’t safe for using anywhere.

The potential danger is that the stay will break most likely locking up the back wheel. It might be merely inconvenient or it might be fatal taken in combination with speed or traffic.

A possible reason for the crack is inappropriate use of the frame e.g jumps, crash damage or it might just be an old cheap Walmart frame which has fatigued.

The frame seems to be alloy from the lack of rust in the fracture. It can’t be fixed within the scope of the bikes probable value. The presence of V brakes and a stamped metal derailleur indicates a low end bike.

Salvage parts if you want and transfer to a not broken frame or just purchase a whole new one. The cost balance on that task will depend on whether you have bike fixing skills and tools or whether you need to take it to a bike shop.

Seriously, don’t use this bike as it is right now.

It's never a reasonable idea to ride a broken frame!
Although in this case maybe it's not too bad. Since the crack is for sure not arose from the stress due to riding. The force will act in the direction of the chainstay and there you might still have enough strength.
If you really want to take the risk, try gluing it with epoxy-metal I had good results with that.

BUT STILL, it will never be a save bike anymore and you should never think about selling it or so.


Brooks saddle angle dilemma I recently got a Brooks B17 and am having trouble finding a comfortable angle. If it's level, I tend to slide forward. If it's angled up to the point where I don't tend to slide forward, I feel pressure on my perineum. A worrisome amount of pressure.

I haven't had such an issue with other saddles (plastic based saddles with cutouts).

With the Brooks I've compromised so it's angled slightly up, slight tendency to slide forward, slight pressure down there.

Q: I'm hoping when it breaks in the tendency to slide forward will be reduced, that my sit bones will create indentations that reduce the forward slide. Anyone know if this will happen? Any tips?

It's a touring setup, saddle about as high as the bar tops.

I noticed the same thing when I first got a B17. I fiddled with various angles and so forth, but in the end I found it's mainly just a matter of getting used to the smoother feel of leather as compared to the plastic you're used to. You slide over leather more easily, especially if you wear typical bike shorts, and this gives you the sensation that you're going to slide forward since you're not used to a smooth surface. But you won't. Your position in the saddle is maintained by your arms and core no matter what sort of saddle you have, not the saddle itself. The smoothness of a leather saddle is actually a benefit, not a drawback, and you'll come to appreciate it if you give it time.

Yes, breaking in helps a bit but it's not necessary. Just getting used to the new feel is all that's necessary.

After a lot of trial and error, I ended up setting my saddle perfectly level just as I had with my plastic saddles. The temptation to tilt the nose upward just because the material is smooth should be resisted, as you've already discovered.

If you are sliding forward YOUR SADDLE IS TOO HIGH. Sliding forward, when the saddle is level, is your legs way to shorten the extension. Do this: level 2/3 of the front of the saddle. If you creep forward or put pressure on your hands lower the saddle in 1/4" increments until you are stable.


Can you help me identify my bike please? Bought this bike off a friend, but it has been repainted and I am just curious as to what kind of bike it is.

Seat, and both tires are not stock. I have replaced all of those since I bought it.

Any ideas would be appreciated. I have been researching the serial number hoping that I may find something. But haven’t. In case that makes any difference the SN is rcy10010578


How can I make my bike (and myself) visible at night? By winter I will be commuting on my bike at night. How can I make my bike as visible as possible to all car drivers?

The obvious few things are:

Front light
Red rear tail light
Spare batteries for said lights
Spoke lights/reflectors for improved side visibility
Bright clothing, ideally cycling clothing with reflective strips on them.

My twist on the hi-viz and flashing lights is to attach the lights backwards so that they're shining onto the vest. It means you're hi-viz pops out like a monument even if the cars' lights are out and you don't have the same blinding effect


Front fork pulling to center / "indexed steering" So I took my bike in to the repair shop, to have the rear wheel replaced, but after the repair I noticed immediately the steering feeling a bit strange.
I've since worked out why.

The problem is that the front forks are somehow pulling the front wheel back to a straight position, each time the front wheel is turned slightly.

I can see this most easily when picking the front wheel up off of the ground, and turning the front handlebars.
The handlebars basically 'snap' themselves back to the straight position, quite strongly.

So it's not related to the wheel, or tyre, since this happens with the wheel completely lifted off the ground.

And it's not related to the brake or gear cables either, since it does exactly the same thing with these cables pulled out of the way manually.

So, as far as I can work out, it must be due to something inside the actual tube of the front forks.

I'm pretty sure it didn't do this before going in to the repair shop (or at least it didn't do this to any noticeable extent).

Note that, based on looking along the wheel, it really seems to centre front wheel quite accurately, and the centring forces seem quite evenly balanced and smooth on either side. So it kind of seems like something that would need to be set up by design (rather than something being randomly broken).

But, this is definitely not something that is desirable for steering, as it makes it difficult for me to steer appropriately when going around bends (since the forks try to pull back to the straight position, which is not what I want when turning).

So the question is: are front forks supposed to do this kind of 'automatic recentring' to some extent?

(I'm thinking perhaps that maybe it used to be much more subtle before going in to the repair shop, so maybe I didn't notice it, and it was ok for steering before, but it somehow got exaggerated.)

If so, is there some way I'm supposed to be able to 'turn down' the effect.

If not, i.e. if front forks are just not supposed to do this, why could this be happening now, and what should I do about it?

This is a usual issue if the bearings in the steering tube are overtightened. Re-adjust the bearing (or take it back to the shop) and you're good to go.

What most likely happened is the guy at the bike shop was pulling  wheelies on the bike after completing the repairs and when the front forks came down on the ground it destroyed the steering head bearings . He didn't touch the front,  and the issue happened after you took it into the shop...


SRAM compatible 11 speed 12-25 cassette? I'm looking for an 11 speed 12-25 cassette compatible with a SRAM drivetrain, however I don't think SRAM makes one.

They list specs for their 11 speed cassettes as follows:

11-25: 11,12,13,14,15,16,17,19,21,23,25
11-26: 11,12,13,14,15,16,17,19,21,23,26
11-28: 11,12,13,14,15,16,17,19,22,25,28
11-30: 11,12,13,14,15,17,19,21,24,27,30
11-32: 11,12,13,14,15,17,19,22,25,28,32

Are there any manufacturers that make a 12-25 that is compatible with SRAM? I'd also be interested in a 12-** cassette as long as it has an 18 tooth cog.

You should read Zinn's articles (a, b, c, probably others) on 11 speed drivetrain compatibility.

The surprising upshot is this: You can swap a Campagnolo 11 speed, Shimano 11 speed and SRAM 11 speed wheel in for each other and they will work (*). You can put SRAM and Shimano cassettes on each other's freehub bodies.

The Shimano Ultegra CS-6800 comes in a 12-13-14-15-16-17-18-19-21-23-25, so this is a cassette you can buy and use.

(*) Zinn notes there might be a tiny amount of indexing adjustment necessary. The SRAM/Shimano swap for wheels isn't really surprising, but the Campagnolo one is.

Shimano cassettes will work with Sram 11 speed, but it will be noisy. Based on experiences and frustration.


How can I install a front brake on this kids bike? Coaster brakes are dangerous and confusing but they keep shipping kid bikes with them for some reason. How can I add a front brake to this bike?

Do not install a front brake to a bicycle that has not been designed for front brakes!!! A front brake requires a frame strong enough for front brake and a fork strong enough for front brake.
There is a quite popular bike sold in my area called Helkama Jopo. It used to be a coaster brake bike with no front brake.
Then, at some point of time someone working for Helkama thought it would be a good idea to switch the steel material of the frame to aluminum, and at the same time install a front brake. Unfortunately they did not design the frame to withstand the loads of a front brake.
The bikes started to fail (the frames cracked and separated in half during use). Some failures resulted in tremendously hurt riders injured for the rest of their life.
The manufacturer claimed that these failures were the result of incorrect use, i.e. jumping and doing wheelies with the bike. Not so!
There is a post in LinkedIn by a mechanical engineer analyzing the issue: https://www.linkedin.com/pulse/miksi-jopo-hajosi-vesa-tiainen
Unfortunately the post is in Finnish, but the mechanical engineer showed that the failures were not due to incorrect use such as jumping and doing wheelies, but they were caused by the manufacturer's decision to install a front brake.
The manufacturer probably realized the mistake, and later front brake versions of the bicycle contained a slight alteration in the frame to prevent peak loads.
The manufacturer still today lies that wheelies and jumping were the cause even though they did a fix to the frame to allow front brake usage, and thus clearly understand that front brake caused peak loads in one part of the frame.
Your frame seems to be exactly the same type as Helkama Jopo, i.e. there are no separate top tube and downtube attached to the headtube. Instead, the top tube and downtube meet earlier and the unified tube attaches to the headtube. This design has exactly the same flaw as the Helkama Jopo design.
Your frame is not strong enough to withstand front brake loads!!!

Sorry but

You have to fix the handle first which doesn't appear to have been fixed in the photo.

And the types of brakes which the cycle have and you are about to install the bicycle I have no idea about them also.

The question needs a detailed answer which I cannot provide you, Sorry for that.
The following pictures may give you some rough idea what you have to do.
(CYCLING IS HEATHY THING), the little kid which is going to get this cycle should be taken care of and have a vigilant eye on him always it can be dangerous.
Thank you.


While on a ride, realised rear disc rotor was contaminated, what could I have done? Last night, commuting, I got lots of dirty water all over my back brake (Promax Render-r mechanical disc), as well as on most of the rest of the bike, and me. I wiped the rotors with a clean rag to get the grit off, because light braking made an unpleasant grinding sound.  This morning I was about 30km into a rather long ride when I realised I had essentially no back brake.  I don't use the back much except to hold back on descents, though I do normally take up the slack when stopping, so it was the first  decent descent when I discovered this.

I can only assume that the water was oily (certainly possible given the state of the roads and the deep puddles last night) and that I spread it evenly over the disc.

So I ended up riding 250km with essentially no back brake.  I would have tried cleaning the rotor with an alcohol sterilising wipe from my first aid kit, but they'd dried up.  I did get a bit off slowing (not stopping) power from holding the brake on all the way down long descents, and cooking it, but presumably this just moved the oil to the pads and finished them off.

I've ordered new pads (front and rear), which I needed soon anyway.  I plan to degrease the rotor, put the used front pads in the back, and see what happens.

Now I've had the chance to remove the wheel and pads, the moving pad on the rear is unevenly worn -- much more wear towards the centre of the rotor.  It was seated properly; I checked after takling the wheel off and before taking the pads out. I don't know whether this wear was cause or effect, as I had the back brake on hard on most downhills for the little effect it did have.  There are some scratches on the back rotor but not much more than the front (or the MTB) and nothing deep like I'd expect if there was a bit of grit preventing proper contact.  The pads were by no means clean but not gritty either.

But what could I have done at the side of the road? There were no bike shops around, but convenience stores and I could probably have found a pharmacy.

Oil and contaminants from the road will float to the top of these puddles and get on the rotors.

Unfortunately once rotors are contaminated, it is EXTREMELY difficult to decontaminate them due to the porous nature of the steel they use for the discs. When you throw fresh pads on, the rotor can contaminate the pads again.

As far as brake pad decontamination, there is hope. What we do here is

Heat the pad up with a blow-torch to expand the pad material
Spray a degreaser on the pad until it stops evaporating instantly
Sand the pad with 120 grit sandpaper until you see new pad material
Clean the pad off by hitting it with the blow-torch or isoprop-alcohol
Reinstall

As far as what could be done on the side of the road, you can try tightening the barrel adjuster for your brake until you can get some form of grip or wiping the contaminants off with the inside of your jersey (That's about it).

If you suddenly lose braking power to both wheels, you can try what BMX riders do and stick the heel of your shoe between the top of your rear tire and your frame.

For a 250 km (150 mile) ride, you should carry spares unless you're in a race.
But for a quick fix, pull the wheel out of the bike and run your trousers (?) belt through between the pads.
Riding with a buddy helps here, which is "another thing" to take on long rides.


Subtle click on left Shimano 4700 STI brake lever when applying brake while moving forward I have a set Shimano Tiagra 4700 levers/shifters on my Niner gravel bike (RLT 9 1 Star) and lately I noticed when moving forward, at speed or slow, there is a subtle click when pulling on the left side lever for the front disc brake -- no matter how light I pull. If it's of any relevance, the brakes on this bike are the stock SRAM BB5 Mechanical disc, Road version, 160mm Avid rotors. The bike is new (just picked it up May and I have about 210 miles on it). I'm not noticing any effect on braking performance but just wondering if this might be a potential problem.

I noticed this after going on a somewhat long ride a few weeks ago with moderate bumps, paved and unpaved as well as loose gravel surfaces. Could this be debris or sediment trapped somewhere in the components? I'm not all that familiar with disc brakes yet so any ideas/suggestions would be greatly appreciated!

Edits from comments:

The lever is quite solid on the handbars and no wobble at all.
The click seems to depend on forward motion while riding. I've tried to replicate it by turning the bike upside down, then spinning the wheel and pulling on the brake lever -- no click, even if the wheel is spun backwards.

Sounds like it could be one of several things:

Loose headset. This is the most probable as it's not uncommon to need to re-adjust the headset as the bike breaks in a little, and it also fits with it being the front brake that's causing this and doing it a little bit with any amount of motion, but not otherwise. You can google "loose threadless headset" and get all the info you need about the topic, but the fast way of determining that it's the headset versus anything else (pad play in this case) is standing beside the bike, locking up the front brake lever with one hand, putting your other hand's fingers right over the gap between the stationary and rotating parts of the headset, and using your body weight to rock the bike forward and back, feeling for any undesirable movement at the gap. Check both the headset uppers and lowers. Lifting the front wheel off the ground a couple inches and dropping it is also a pretty good test on a rigid-forked bike that's not too junked up with accessories, although if there's any clunking you have to then differentiate whether it's from the headset or front hub.
Play from the front pads moving in the caliper. Most or all disc brakes have some degree of this, but usually the amount you can feel while riding is on the very subtle side, and it's also not usually an acquired problem, i.e. it stays the same for a given brake or set of pads. If you determine that this is what it is, there's nothing you can really do about it.
Theoretically, loose caliper or rotor bolts. Easy to check, and you'd be getting brake rub.

Not sure if we're having the same problem, but I recently raised the handlebars on my whip and didnt fully tighten the retaining nuts for the quill stem. When I would use the front brakes, there would be an audible click and the handlebars would shift forward very slightly. I tightened the nut, and now it's solid.

If I were you, I would spin the front wheel as fast as you can (not riding) and use the brake to see if the click happens. Do this upside down and upright. If you don't hear the click, it's likely the motion of riding that is causing something to shift. Bikes should be solid, so any shifting that isn't your chain should be looked into.

Also, a friend of mine has those fancy-schmancy brake-shifter-in-one levers and I've noticed when I ride his bike that when I pull the levers to brake, I also accidentally move the derailleur over just a little bit. If you're doing that unintentionally, it may be just enough to make the derailleur (front, I assume) rub the chain (clicking sound) , but not enough to push it onto the next chainring.

All in all, the best way to solve your problem would be to pay super super close attention to it. Find a quiet street with few cars and ride up and down that street, staring at where it looks like the clicking is, braking, looking, braking, looking...until you localize it, or go crazy.