From: iglesias@draco.acs.uci.edu (Mike Iglesias)
Subject: Rec.Bicycles Frequently Asked Questions Posting  Part 3/4
Expires: 5 May 1992 00:00:00 GMT
Newsgroups: rec.bicycles,news.answers
Organization: University of California, Irvine
Date: 7 Apr 92 02:48:21 GMT
Followup-To: rec.bicycles

Archive-name: bicycles-faq/part3

[Note:  The complete FAQ is available via anonymous ftp from 
draco.acs.uci.edu (128.200.34.12), in pub/rec.bicycles.]

===========================================================================

Chains


Lubricating Chains

Lubricating chains is a somewhat religious issue.  Some advocate oil,
some Teflon-base lubricants, some paraffin wax.  The net majority favors
a lubricant that does not leave an oily coating on the chain that can
attract dirt, which will hasten chain/chainring/freewheel sprocket wear.

If you want to use paraffin wax, make sure you melt the wax in a double
boiler!  Failure to do so can lead to a fire.  You can use a coffee
can in a pan of boiling water if you don't want to mess up good cookware.
After the wax has melted, put the chain in the wax and simmer for 10
minutes or so.  Remove the chain, hang it up, and wipe the excess wax
off.  Let it cool and reinstall on your bike.

When using a liquid lubricant, you want to get the lube onto the pins
inside the rollers on the chains, not on the outside where it does little
good.  Oilers with the narrow tubes are good for this because you can put
the lube where you want it.  Work the oil into the chain after applying
it, wipe the chain off, and reinstall on your bike.

---------------------------------------------------------------------------

Wear and Gear Slippage  (Jobst Brandt  jobst_brandt%40@hp1900.desk.hp.com)

There seems to be a lot of speculation on what makes chains wear
and how to lubricate a chain.  There are a number of ways to take
care of a chain.  Some traditional methods are the most damaging
to chain life and others work to prolong life.

As was mentioned on the net, chains don't stretch in the sense
that the metal elongates, but the parts wear.  Wear in the pins
and sleeves change the length of the chain as the pins fit more
loosely.  The wear arises primarily from road grit that enters
the chain when it is oiled.  Grit on the outside of a chain looks
bad but it has no effect on the function because it can't get
inside to do damage.  Only when a dirty chain is oiled does this
grit get to the place where it can cause damage.  Note that
commercial abrasive grinding paste is made of oil and silicon
dioxide (sand) and silicon carbide (sand).  You couldn't do a
better job if you tried to destroy a chain than to oil a road
dirt (previously oiled) encrusted chain.

Primitive rule #1:  Never oil a chain on the bike.

This means you should clean the grit off the chain before oiling
it.  Because this is essentially impossible without submerging
the chain in a solvent bath (kerosene or commercial solvent), you
must take the chain off the bike.  The fine grit can only be
removed from the interior of the chain in liquid suspension.  A
good example of this can be seen by using a Vetta (on the bike)
chain cleaner and subsequently cleaning the same chain in a
solvent bath.  The best grit remains until last and there's
plenty of it.

Removing the solvent from the chain after the rinse is important.
Compressed air is not readily available in the household nor is a
centrifuge.  You can go outdoors and sling the chain around.
This works best if the chain is a closed loop.  You don't have to
press the pin completely in for this.  The other way is to
evaporate it.  You should probably avoid accelerated drying
methods because they could be explosive.

The hot gear lube method works but it also acts as efficient fly
paper, collecting plenty of grime between cogs.  Motor oil is good
but motorcycle chain lubes are better because they have volatile
solvents that allow good penetration for relatively viscous
lubricant.  Paraffin is useless because it is not mobile and
cannot replenish the bearing surface once it has been displaced.

Sedisport

The Sedisport chain, although the strongest and one of the
lightest chains, achieves its light weight at the expense of
durability.  This chain has omitted the sleeve that on most
roller chains supports the roller on its outside and furnishes
the bearing for the pin on the inside.  Normally the inside of
the sleeve is well protected against lubricant depletion because
both ends are covered by closely fitting side plates.  In the
Sedisport there is no sleeve and the formed side plates support
the roller and pin with a substantial central gap.  In the wet,
lubricant is quickly washed out of pin and roller and the inferior
bearing for the pin and roller often gall and bind.  In good
weather this is not a problem.  Because this chain has feet of
clay in the wet, Sedis re-introduced their earlier 5 element
conventional chain, calling it a "chain for all seasons".

The lightweight Regina chain goes one step farther and omits the
pin, leaving the side plates to hinge directly on the sleeve.
This gives them a knife edge bearing area that galls at the
slightest lube depletion.

Chain Life

This is almost entirely a cleanliness and lubrication question
rather than a load problem.  The effect of load variations is
insignificant when compared to the lube and grit effects for
bicycles.  The primary chains on motorcycles are operated under
clean conditions and last years while the exposed rear chains
must be replaced often.

The only way to test whether a chain is worn is by measurement.
The chain has a half inch pitch and, when new, has a pin at
exactly every half inch.  As the pins and sleeves wear this
spacing increases and becomes damaging to sprockets.  When the
chain pitch grows over one half percent it is time for a new
chain.  At one percent chainring damage progresses rapidly.  By
holding a ruler along the chain on your bile, align an inch mark
with a pin and see how far off the mark the pin is at twelve
inches.  An eighth of an inch (0.125) is the ten percent limit
while more than a sixteenth is a prudent time to get a new chain.

Skipping Chain

When you put on a new chain, its pitch is exactly one half inch.
A sprockets worn by a longer pitch chain pockets in its teeth.
These pockets are formed by the rollers of a worn chain as they
exit the sprocket under load.  Rollers of a new chain with
correct pitch exit under no load because the load is transferred
to the next roller before disengagement.  However, with hooked
sprockets the new chain cannot engage under load because the
pitch is too small to get over the hook and into the pocket.
These differences are only a few thousandths of an inch but that
is enough to prevent engagement when the previous roller is in
its pocket.

As a chain wears it concentrates more of its load on the last
tooth of a sprocket before disengagement because its pitch no
longer matches the pitch of the sprocket.  This effect sometimes
breaks off sprocket teeth.  The load concentration on the
sprocket also accelerates wear and is another reason to replace a
chain at 1/16th inch wear.

---------------------------------------------------------------------------

Adjusting Chain Length  (Bob Fishell  spike@cbnewsd.att.com)

For all Shimano SIS and Hyperglide systems, the chain is sized by shifting to
the smallest rear cog and the largest front sprocket, then sizing the
chain so that the derailleur pulleys are on a vertical line, or as close
as you can get to it.  Note that this will result in the same chain length
for any freewheel within the capacity of the derailleur, so it usually is
not necessary to re-size the chain for a different cogset with these systems.

The other rule I've used (friction systems) involves shifting to the largest
chainring and the largest rear cog, then sizing the chain so that the pulleys
are at a 45 degree angle to the ground.

The rules probably vary from derailleur to derailleur.  In general,
you may use the capacity of the rear derailleur cage as a guideline. You
want the chain short enough so the cage can take up the slack in the 
smallest combination of chainwheel and rear cog you will use. The chain
must also be long enough so that the cage still has some travel in the
largest combination you will use.

For example, if you have a 42x52 crank and a 13x21 freewheel, the smallest
combination you would use would be a 42/14 (assuming you don't use the
diagonal). If the cage can take up the slack in this combo, it's short enough.
If the cage has spring left when you are in the 52/19 combo (again, you are
not using the diagonal), it's long enough.

---------------------------------------------------------------------------

Hyperglide chains

When you need to replace a Shimano Hyperglide chain, use a Sedis ATB
chain.  It's compatible with the Hyperglide system and doesn't need
a special pin to put the chain back together when you take it apart.

===========================================================================

Cranks and Bottom Brackets

Bottom Bracket Info  (Jobst Brandt  jobst_brandt%40@hp1900.desk.hp.com)

The four kinds of BB threads in common use today are Italian, British,
French, and Swiss, possibly in that order of occurrence.

           Diameter   Pitch    Right Left Cup
           --------   -----    ----- -----
Italian    36mm   x   24F tpi  right right        tpi (threads per inch)
British    1.370" x   24F tpi  left  right
French     35mm   x   1mm      right right
Swiss      35mm   x   1mm      left  right

Unless there is something wrong with the right hand cup it should not be
removed but should be wiped clean and greased from the left side.  The
thread type is usually marked on the face of both left and right cups.
Swiss threads are rare but if you have one it is good to know before
attempting removal.

---------------------------------------------------------------------------

Crank noises  (Phil Etheridge  phil@waikato.ac.nz)

I've had the creaky crank problem on every bike I've owned which has
had cotterless cranks.  Until now, I've never known a good solution to
the problem.  

One suggestion I had was to replace the crank, but that wasn't
something I was prepared to do on 1 month old bike under warranty. 
The shop mechanic spent half an hour with me and my bike sorting it
out.  Tightening the crank bolts and pedal spindle (i.e. onto the
crank) didn't help (as Jobst will tell you).  

Removing each crank, smearing the spindle with grease and replacing
the crank eliminated most of the noise.  Removing each pedal, smearing
grease on the thread and replacing it got rid of the rest of the
noise.

Greasing the pedal threads is a new one on me, but it makes a lot of
sense, since they are steel and the crank aluminum.  I thought it was
worth relating this story, as creaky cranks seems to be quite a common
problem.

---------------------------------------------------------------------------

Cracking/Breaking Crankarms  (Jobst Brandt  jobst_brandt%40@hp1900.desk.hp.com)

[Ed note:  Yes, another disputed issue is contained here - whether to
lube the crank tapers before installing the crankarms.  This has
popped up from time to time on rec.bicycles, and has never been
resolved one way or the other.  The text here is Jobst's viewpoint.]

Cranks break because they are aluminum and because they have high
stress at various points.  The worst of these points are at the
pedal eye and where the spider fingers join the right crank.  The
pedal eye is a bad place because the joint is incorrectly designed,
but since it is a standard, it may not be changed since it seems to
work.  This joint always moves and causes fretting corrosion and
cracks.  These cracks propagate into the crank and cause failure.
A better joint here would be a 45 degree taper instead of a flat
shoulder at the end of the pedal thread.

The thin web between the spider and crank, another common crack
origin on cranks like the Campagnolo Record, was nicely redesigned
in the C-Record crank, but to make up for that the C-Record is
otherwise weaker than the Record version.  My experience is that
they break in about 1500 miles because the pedal eye has a smaller
cross section than the Record model, but maybe the alloy is poorer
too.  I have subsequently used Dura Ace cranks for more than two
years with no failure yet.  I don't believe in eternal life here
either.

Aluminum has no safe fatigue limit but just gets progressively safer
as stress is reduced.  In contrast, steel has a threshold below
which failures cease.  Therein lies some of the problem.

As for cranks loosening, one can view the junction between spindle
and crank in an exaggerated elastic model where the spindle is made
of plastic and the crank of Rubbermaid household rubber.  The crank,
once properly installed and the retaining bolt in place, squirms on
the square taper when under torque.  During these deformations the
crank can move only in one direction because the bolt prevents it
from coming off.  The crank always slides farther up the taper.
Proof that the crank squirms is given by the fretting rouge always
found on the spindle, whether lubricated or not, when a crank is
pulled off after substantial use.

As was mentioned by various observers, the left crank bolt is
usually looser, after use, than the right one and this could be
anticipated because the two cranks differ in their loading.  This
does not mean the left crank is looser.  Actually it is tighter,
only the bolt is looser.  The left crank is more heavily loaded
because it experiences offset twist from the pedal at the same time
it transmits torque to the spindle.  The right crank, being
connected to the chain, experiences either spindle torque from the
left pedal or twist from the right pedal but not torque and twist at
the same time.

In this squirming mode, cranks wander away from the retaining bolt
and leave it loose after the first hard workout (for riders of more
than 150 lbs).  The bolts should NOT be re-tightened because they
were correctly tight when installed.  Cranks have been split in half
from repeated follow-up tightening, especially left cranks.  The
spindle should be lubricated before installing cranks.  A wipe of a
mechanic's finger is adequate since this is to prevent galling in
the interface.  To prevent losing a loose crank bolt, the "dust"
cover that is in fact the lock cap should be installed.

Those who have had a crank spindle break, can attest to the greater
stress on the left side because this is the end that always breaks
from fatigue.  A fatigue crack generally has a crystalline
appearance and usually takes enough time to develop that the face of
the fracture oxidizes so that only the final break is clean when
inspected.  Because a notch acts to concentrate stress, the
advancing crack amplifies this effect and accelerates the advance
once the crack has initiated.

I have heard of instructions to not lubricate spindles before
installing cranks but I have never been able to find it in any
manufacturer's printed material.  Although I have broken many
Campagnolo cranks, none has ever failed at the spindle.  I am
certain that the standard machine practice of lubricating a taper
fit has no ill effects.  I have also never had a crank come loose
nor have I re-tightened one once installed.

---------------------------------------------------------------------------

Biopace chainrings

Biopace chainrings have fallen into disfavor in recent years.  They
are hard to "pedal in circles".  The early Biopace chainrings were
designed for cadences of around 50-70 rpm, while most recommend a
cadence of 80-100 rpm.  Newer Biopace chainrings are less elliptical,
but the general consensus is to (if you are buying a new bike) get the
dealer to change the chainrings to round ones.

===========================================================================

Tires and tubes

Snakebite flats

Snakebite flats are usually caused by the tire and tube being pinched
between the road and the rim, causing two small holes in the tube that
look like a snakebite.  The usual causes are underinflation, too
narrow a tire for your weight, or hitting something (rock, pothole)
while having your full weight on the tire.

The obvious solutions are to make sure your tires are inflated properly,
use a larger size tire if you weigh a lot, and either avoid rocks and
potholes or stand up with your knees and elbows flexed (to act like shock
absorbers) when you go over them.

---------------------------------------------------------------------------

Blown Tubes  (Tom Reingold  tr@samadams.princeton.edu)

Charles E Newman writes:

$ 	 Something really weird happened at 12:11 AM. My bike blew a
$ tire while just sitting parked in my room. I was awakened by a noise
$ that scared the livin ^&$% out of me. I ran in and found that all the
$ air was rushing out of my tire. How could something like happen in the
$ middle of the night when the bike isn't even being ridden? I  have
$ heard of it happening when the bike is being ridden but not when it is
$ parked.

This happened because a bit of your inner tube was pinched between your
tire bead and your rim.  Sometimes it takes a while for the inner tube
to creap out from under the tire.  Once it does that, it has nothing to
keep the air pressure in, so it blows out.  Yes, it's scary.  I've had
it happen in the room where I was sleeping.

To prevent this, inflate the tire to about 20 psi and move the tire
left and right, making sure no part of the inner tube is pinched.

---------------------------------------------------------------------------

Mounting Tires   (Douglas Gurr  dgurr@daimi.aau.dk)

A request comes in for tyre mounting tricks. I suspect that this ought to be
part of the FAQ list. However in lieu of this, I offer the way it was taught
to me. Apologies to those for whom this is old hat, and also for the paucity
of my verbal explanations. Pictures would help but, as always, the best bet
is to find someone to show you.

First of all, the easy bit:

1) Remove the outer tyre bead from the rim. Leave the inner bead.
   Handy hint. If after placing the first tyre lever you
   are unable to fit another in because the tension in the bead is too great
   then relax the first, slip the second in and use both together.
2) Pull out the tube finishing at the valve.
3) Inspect the tube, find the puncture and repair it.

Now an important bit:

4) Check tyre for thorns, bits of glass etc - especially at the point where
   the hole in the tube was found.

and now a clever bit:

5) Inflate the tube a _minimal_ amount, i.e. just sufficient for it to
   hold its shape. Too much inflation and it won't fit inside the tyre.
   Too little (including none at all) and you are likely to pinch it.

More important bits:

6) Fit the tube back inside the tyre. Many people like to cover the tube in
   copious quantities of talcum powder first. This helps to lubricate
   the tyre/tube interface as is of particular importance in high pressure
   tyres.
7) Seat the tyre and tube over the centre of the rim.
8) Begin replacing the outer bead by hand. Start about 90 degrees away from
   the valve and work towards it. After you have safely passed the valve,
   shove it into the tyre (away from the rim) to ensure that you have
   not trapped the tube around the valve beneath the tyre wall.

Finally the _really_ clever bit:

9) When you reach the point at which you can no longer proceed by hand,
   slightly _deflate_ the tube and try again. Repeat this process until
   either the tyre is completely on (in which case congratulations)
   or the tube is completely deflated. In the latter case, you will have
   to resort to using tyre levers and your mileage may vary. Take care.

and the last important check:

10) Go round the entire wheel, pinching the tyre in with your fingers
    to check that there is no tube trapped beneath the rim. If you
    have trapped the tube, deduct ten marks and go back to step one.
    Otherwise ....

11) Replace wheel and reinflate.

---------------------------------------------------------------------------

More Flats on Rear Tires  (Jobst Brandt  jobst_brandt%01@hp1900.desk.hp.com)

Most sharp obstacles except tetrahedral glass slivers and puncture
vine gets stuck more often is that the front tire upsets the sharp
object just in time for the rear tire to catch it head-on. 

This front to rear effect is also true for motor vehicles.  Nails lying
on the road seldom enter front tires.  When dropped on the road by a
moving vehicle, the nail slides down the road aligning itself pointing
toward traffic because it tends to roll around until it is head first.
The tire rolls over it and tilts it up so that if the speed is ideal,
the rear tire catches it upright.  I once got a flat from a one inch
diameter steel washer that the rear tire struck on edge after the front
tire flipped it up.

When it is wet glass can stick to the tire even in the flat orientation
and thereby get a second chance when it comes around again.  To add to
this feature, glass cuts far more easily when wet as those who have cut
rubber tubing in chemistry class may remember.  A wet razor blade cuts
latex rubber tubing in a single slice while a dry blade only makes a
nick.

---------------------------------------------------------------------------

Anodized vs. Non-anodized Rims  (Jobst Brandt  jobst_brandt@hplabs.hp.com)

There are several kinds of dark coatings sold on rims.  Each suggests that
added strength is achieved by this surface treatment while in fact no useful
effects other than aesthetic results are achieved.  The colored rims just
cost more as do the cosmetically anodized ones.  The hard anodized rims do
not get stronger even though they have a hard crust.  The anodized crust is
brittle and porous and crazes around spoke holes when the sockets are riveted
into the rim.  These cracks grow and ultimately cause break-outs if the
wheel is subjected to moderate loads over time.

There is substantial data on this and shops like Wheelsmith, that build many
wheels, can tell you that for instance, no MA-2 rims have cracked while MA-40
rims fail often.  These are otherwise identical rims.

Hard anodizing is also a thermal and electrical insulator.  Because heat is
generated in the brake pads and not the rim, braking energy must cross the
interface to be dissipated in the rim.  Anodizing, although relatively thin,
impedes this heat transfer and reduces braking efficiency by overheating the
brake pad surfaces.  Fortunately, in wet weather, road grit wears off the
sidewall anodizing and leaves a messy looking rim with better braking.

Anodizing has nothing to do with heat treatment and does not strengthen rims.
To make up for that, it costs more.

---------------------------------------------------------------------------

Clinchers vs. Tubulars  (F.J. Brown  F.Brown@massey.ac.nz)

D.H.Davis@gdt.bath.ac.uk gave some useful hints on mounting clinchers,
mostly involving the use of copious quantities of baby powder, and
trying to convince me that clinchers aren't difficult to mount, so ease of 
mounting isn't a valid reason for preferring tubulars.

wernerj@lafcol.lafayette.edu wrote that although average tubulars ride
'nicer' than average clinchers, there are some clinchers around that ride
just as 'nice'.   He also said that ease of change isn't a good reason for
preferring tubulars as if you flat in a race, you're either going to swap
a wheel or drop out.   He pointed out that tubulars end up costing $20 -
$80 per flat.

ershc@cunyvm.cuny.edu gave some of the historic reasons that tubulars were
preferred: higher pressures, lower weight, stronger, lighter rims.   Said
that only a few of these still hold true (rim strength/weight, total weight),
but he still prefers the 'feel' of tubulars.

leka@uhifa.ifa.hawaii.edu started this thread with his observations on 
clinchers seperated from their rims in the aftermath of a race crash.

stek@alcvax.pfc.mit.edu comments on improperly-glued tubulars posing a threat 
to other racers by rolling off, and noted that this couldn't happen with 
clinchers.

jobst_brandt@hplabs.hp.com agreed with stek, with the additional note that 
it is inadequate inflation that often allows tubulars to roll.

Kevin at Buffalo agreed with stek and jobst about tubulars (improperly or
freshly glued) sometimes rolling.

ruhtra@turing.toronto.edu says he uses clinchers for cost and convenience.
Clinchers let him carry around a tiny patch kit and some tyre irons, costing
60c, whereas tubulars would require him to carry a whole tyre, and would 
cost more.    

CONCLUSIONS: THE CLINCHER VS. TUBULAR WAR
Tubulars - used to be capable of taking higher pressures, had lower weight 
           and mounted onto stronger, lighter rims than clinchers.   Clinchers
           have now largely caught up, but many cyclists thinking hasn't.   
           Tubular tyre + rim combination still lighter and stronger.
         - are easier to change than clinchers.   This matters more to some 
           people than others - triathletes, mechanical morons and those 
           riding in unsupported races.
         - cost megabucks if you replace them every time you puncture.   
           ***However*** (and none of the North Americans mentioned this)
           down here in Kiwiland, we ***always*** repair our punctured
           tubulars (unless the casing is cut to ribbons).   The process
           doesn't take much imagination, you just unstitch the case, repair 
           the tube in the normal manner using the thinnest patches you can 
           buy, stitch it back up again and (the secret to success) put a
           drop of Superglue over the hole in the tread.
         - can roll off if improperly glued or inflated.   In this case, you
           probably deserve what you get.   Unfortunately, the riders behind
           you don't.

Clinchers - can be difficult to change (for mechanical morons) and are always
            slower to change than tubulars.   Most people still carry a spare
            tube and do their repairs when they get home.    
          - are cheaper to run: if you puncture a lot clinchers will probably 
            still save you money over tubulars, even if you repair your 
            tubulars whenever possible.   Tubulars are only repairable most 
            of the time, you virtually never write off a clincher casing due 
            to a puncture. 
          - have improved immensely in recent years; top models now inflate
            to high pressures, and are lighter and stronger than they used
            to be.   Likewise clincher rims.   Some debate over whether
            tubulars are still lighter and tubular rims stronger.   Probably
            depends on quality you select.   No doubt that high quality 
            clinchers/rims stronger, lighter and mor dependable than cheap
            tubular/rim combination.

---------------------------------------------------------------------------
Brakes

Center Pivot vs. Dual Pivot Brakes  (Jobst Brandt  jobst_brandt@hplabs.hp.com)

Sidepull (one central pivot) brakes operate at a small angle to the
rim.  That means the pad moves in a nearly perpendicular direction to
the braking surface and the pads can be completely worn down without
adjusting their position.  The unit is light and has a self contained
quick release and cable adjustment feature.

Its weakness is its thin arms that, in the pursuit of light weight,
flex in the bending direction.  With the current practice to minimize
tire clearance on road bicycles, sidepull brakes cannot be used off
road for lack of dirt clearance.  Their return spring is anchored in a
way that relative motion occurs between it and the brake arms.  This
motion demands lubrication and in its absence the brake does not
center itself.  This is a perpetual problem that has not been solved
and has given rise to many designs, the latest of which is the Shimano
dual pivot brake.  This brake has the disadvantage that it cannot
track a wobbly wheel because it is forced to be centered.

The cantilever and centerpull brakes are inversions of the same
design.  Both have pivot points that are at 45 degrees to the brake
surface, but the centerpull offers no advantage over sidepulls because
it has all the same problems and not the advantages.  In contrast the
cantilever is the most rigid of available brakes and offers more tire
clearance for off road use.

The approach angel moves the brake pads in an undesirable direction so
that as the pad wears it must be adjusted to prevent falling off the
rim.  With wear, the centerpull goes into the tire while the
cantilever allows the pad to pop under the rim, never to return.
Cantilever brakes have the additional problem that their reaction
force spreads the forks.  For this reason, U shaped stress plates are
made to contain this force.  For forks with telescopic suspension,
braking restricts forks motion.

Nearly all bicycle brakes have about the same mechanical advantage
(4:1) that arises primarily in the hand lever.  The "calipers" all
approximate a 1:1 ratio.  This is necessary to fit the reach of the
average hand and the strength of the hand in proportion to body
weight.  That is to say all brakes are made to about the same human
specification.  Force and motion are a trade-off and this is the
result.

The Campagnolo Delta and Modolo Chronos brakes have a variable ratio
that at the extremes ranges from infinity to zero, its motion being
generated by an equilateral parallelogram that changes from one
extreme to the other.  This is an undesirable feature, especially as
the pads wear and braking takes place in the zone of increased lever
travel and increased mechanical advantage.  The brake bottoms out
abruptly.

Servo activation on cantilever brakes has been offered in a design that
uses the forward thrust on the brake post to add force to the
application.  Self servo effects are undesirable in brakes because the
proportionality between braking and hand force is lost.  You don't
know how much braking you will get for a given hand lever force.  It
can vary widely and in some circumstances cause an unwanted skid.

===========================================================================

Adjustments and Repairs

Seat adjustments   (Roger Marquis  marquis@qal.berkeley.edu)

     The following method of setting saddle height is not the
only method around for setting your saddle height but it is the
most popular among coaches and riders both here and in Europe.
 
     A) Adjust saddle level or very slightly nose up, no more
        than 2mm at the nose.
     B) Put on the shoes you normally ride in. Have wrench ready
        (usually a 5mm Allen).
     C) Mount the bike and sit comfortably, leaning against a
        wall. Hold the brake on with one hand (or mount the bike
        on a turbo trainer if you have one).
     D) Place your HEELS on the pedals, opposite the clip, pedal
        backwards at 30+ rpm without rocking your pelvis (very
        important).
     E) Adjust seat height so that there is about:
      1) ZERO TO ONE HALF CM. for recreational riders
         (-50 mi/wk.),
      2) ONE HALF TO ONE CM. for experienced riders
         (50+ mi./wk.),
      3) ONE TO TWO CM. for endurance cyclists (250+ mi./wk.),
         between your heel and the pedal. If your soles are
         thicker at the cleat than at the heel adjust accordingly.
        Don't forget to grease the seat post.
     F) Ride. It may take a couple of rides to get used to the
        feel and possibly stretch the hamstrings and Achilles
        slightly.
 
---------------------------------------------------------------------------

Cleat adjustments   (Roger Marquis  marquis@qal.berkeley.edu)

[Ed note:  You may also want to consider going to a bike shop that does
Fit Kit and have them do the Fit Kit RAD to adjust your cleats.  Many
people recommend it.]

     A) Grease the cleat bolts and lightly tighten.
     B) Sitting on the bike, put your feet in the pedals and
        adjust until:
     B1) The ball of your foot is directly above or, more         
         commonly, slightly behind the pedal axle and:
     B2) There is approximately 1 cm. (1/2in.) between your ankle
         and the crank arm.
     C) Tighten the cleat bolts 80% and go out for a ride.
        If another position feels more comfortable rotate
        your foot into that position.
     D) Carefully remove your shoes from the pedals and tighten
        the bolts fully. If you cannot get out of the pedals
        without shifting the cleats leave your shoes on the bike
        and draw an outline around the cleat.

---------------------------------------------------------------------------

SIS Adjustment Procedure  (Bob Fishell  spike@cbnewsd.att.com)

Shimano's instructions for adjusting SIS drivetrains varies from series
to series.  The following method, however, works for each of mine (600EX,
105, and Deore').  [Ed note:  Works on Exage road and mtb also.]

Your chain and cogs must be in good shape, and the cable must be free
of kinks, slips,  and binds.  The outer cable should have a liner.
clean and lubricate all points where the cable contacts anything.

SIS adjustment:

1) Shift the chain onto the largest chainwheel and the smallest cog,
   e.g., 52 and 13.

2) WITHOUT TURNING THE CRANKS, move the shift lever back until it
   clicks, and LET GO.  This is the trick to adjusting SIS.

3) Turn the crank.  If the chain does not move crisply onto the next
   inside cog, shift it back where you started, turn the SIS barrel
   adjuster (on the back of the rear derailleur) one-half turn CCW,
   and go back to step 2.  Repeat for each pair of cogs in turn
   until you can downshift through the entire range of the large
   chainwheel gears without the chain hesitating.  If you have just
   installed or reinstalled a shift cable, you may need to do this
   several times.

4) Move the chain to the small chainring (middle on a triple) and the 
   largest cog.

5) turn the cranks and upshift.  If the chain does not move crisply
   from the first to the second cog, turn the SIS barrel adjuster
   one-quarter turn CW.

If the drivetrain cannot be tuned to noiseless and trouble-free
SIS operation by this method, you may have worn cogs, worn chain,
or a worn, damaged, or obstructed shift cable.  Replace as needed
and repeat the adjustment.

===========================================================================

Tools and Workstands

Where to buy tools

You can buy tools from many sources.  Some tools can be purchased at
your local hardware store (wrenches, socket sets, etc), while the
special bike tools can be purchased from your local bike store or
one of the mail order stores listed elsewhere.

You can buy every tool you think looks useful, or just buy the tools
you need for a particular repair job.  Buying the tools as you need
them will let you build up a nice tool set over time without having
to drop a lot of money at once.

Some common tools you will need are:

  Metric/SAE wrenches for nuts and bolts (or an assortment of adjustable
    wrenches).
  Screwdrivers, both flat and phillips.
  Metric allen wrenches.
  Pliers.
  Wood or rubber mallet for loosening bolts.

Special tools and their uses:

  Cone wrenches to adjust the hub cones.
  Chain tool to take the chain apart for cleaning and lubrication, and
    to put it back together.
  Tire irons for removing tires.
  Spoke wrenches for adjusting spokes.
  Cable cutters for cutting cables (don't use diagonal pliers!).
  Crankarm tools for removing crankarms.
  Bottom bracket tools for adjusting bottom brackets.
  Headset wrenches to adjust the large headset nut.
    
---------------------------------------------------------------------------

Workstands

There are a variety of workstands available, from about $30 to over
$130.  Look at the mail order catalogs for photos showing the different
types.  The type with a clamp that holds one of the tubes on the bike
are the nicest and easy to use.  Park has a couple of models, and their
clamp is the lever type (pull the lever to lock the clamp).  Blackburn
and Performance have the screw type clamp (screw the clamp shut on the
tube.

If you have a low budget, you can use two pieces of rope hanging from 
the ceiling with rubber coated hooks on the end - just hang the bike
by the top tube.  This is not as steady as a workstand, but will do
an adequate job.

===========================================================================

Riding Techniques

Descending I  (Roger Marquis  marquis@qal.berkeley.edu)

     Descending ability, like any other skill, is best improved 
with practice. The more time you can spend on technical descents 
the more confidence and speed you will be able to develop. A few 
local hot shots I know practice on their motorcycles before races 
with strategic descents. While frequent group rides are the only 
way to develop real bike handling skills descending with others 
will not necessarily help you descend faster alone.

     The most important aspect of fast descending is relaxation. 
Too much anxiety can narrow your concentration and you will miss 
important aspects of the road surface ahead. Pushing the speed to 
the point of fear will not help develop descending skills. Work 
on relaxation and smoothness (no sudden movements, braking or 
turning) and the speed will follow.

     A fast descender will set up well in advance of the corner 
on the outside, do whatever braking needs to be done before 
beginning to turn, hit the apex at the inside edge of the road, 
finally exiting again on the outside (always leaving some room 
for error or unforeseen road hazard). The key is to _gradually_ 
get into position and _smoothly_ follow your line through the 
corner. If you find yourself making _any_ quick, jerky movements 
take them as a sign that you need to slow down and devote a 
little more attention further up the road.

     Use your brakes only up to the beginning of a corner, NEVER 
USE THE BRAKES IN A CORNER. At that point any traction used for 
braking significantly reduces the traction available for 
cornering. If you do have to brake after entering the curve 
straighten out your line before applying the brakes. If the road 
surface is good use primarily the front brake. If traction is 
poor switch to the rear brake and begin breaking earlier. In auto 
racing circles there are two schools of thought on braking 
technique. One advocates gradually releasing the brakes upon 
entering the corner, the other advises hard braking right up to 
the beginning of the curve and abruptly releasing the brakes just 
before entering the curve. A cyclists would probably combine the  
techniques depending on the road surface, rim trueness, brake pad 
hardness and the proximity of other riders.

     Motorcyclists and bicyclists lean their bikes very 
differently in a corner. When riding fast motorcyclists keep 
their bikes as upright as possible to avoid scraping the bike. 
Bicyclists on the other hand lean their bikes into the corner and 
keep the body upright. Both motorcyclists and bicyclists extend 
the inside knee down to lower the center of gravity. To _pedal_ 
through the corners make like a motorcyclists and lean the bike 
up when the inside pedal is down. 

     One of the most difficult things about descending in a group 
is passing. It is not always possible to begin the descent ahead 
of anyone who may be descending slower. If you find yourself 
behind someone taking it easy either hang out a safe distance 
behind or pass very carefully. Passing on a descent is always 
difficult and dangerous. By the same token, if you find yourself 
ahead of someone who obviously wants to pass, let them by at the 
earliest safe moment. It's never appropriate to impede someone's 
progress on a training ride whether they are on a bicycle or in a 
car. Always make plenty of room for anyone trying to pass no 
matter what the speed limit may be. Be courteous and considerate 
and you'll be forever happy. 

     Remember that downhill racing is not what bicycle racing is 
all about. There is no need to keep up with the Jones'. This is 
what causes many a crash. Compete against yourself on the 
descents. Belgians are notoriously slow descenders due to the 
consistently rainy conditions there. Yet some of the best 
cyclists in the world train on those rainy roads. Don't get 
caught pushing it on some wet or unfamiliar descent. Be prepared 
for a car or a patch of dirt or oil in the middle of your path 
around _every_ blind corner no matter how many times you've been 
on a particular road. Take it easy, relax, exercise your powers 
of concentration and hammer again when you can turn the pedals. 

     If you're interested in exploring this further the best book 
on bike handling I've read is "Twist of The Wrist" by motorcycle 
racer Keith Code. There is also data out there (Cycle Magazine) 
on eye exercises designed to train depth perception adjustment, 
peripheral vision and concentration. If you know where I can   
find this information please send it to:

     NCNCA District Coaching Office
     Roger Marquis
     782 San Luis Rd.
     Berkeley, Ca 94707

---------------------------------------------------------------------------

Descending II  (Jobst Brandt  jobst_brandt@hplabs.hp.com)

The Art of Descending  (an assessment)

Descending on a bicycle requires a combination of skills that are
more commonly used in motorcycling.  Only when descending does the
bicycle have the power and speed that the motorcycle encounters
regularly, not to say that criterium racing doesn't also challenge
these skills.  It requires a combination of lean angle and braking
while selecting an appropriate line through curves.  Unlike
motorcycle tires, bicycle tires have little margin and even a small
slip on pavement is usually unrecoverable.  Understanding the forces
involved and how to control them is more natural to some than
others.  For some these skills may have atrophied from disuse at an
early age and need to be regenerated.

How to Corner

Cornering is the skill of anticipating the appropriate lean angle
with respect to the ground before you get to the apex of the turn.
The angle is what counts and it is limited by traction.  This means
you must have an eye for traction.  For most pavement this is about
45 degrees in the absence of oil, water or other smooth and slick
spots.  So if the curve is banked 10 degrees, you could lean to 55
degrees from the vertical.  In contrast, a crowned road with no
banking, where the surface falls off about 10 degrees, would allow
only 35 degrees (at the limit).

Estimating the required lean angle for a curve is derived from the
apparent traction and what your speed will be in the apex of the
turn at the current rate of braking.  Anticipating the lean angle is
something humans, animals and birds do regularly in self propulsion.
When running you anticipate how fast and sharply you can turn on the
sidewalk, dirt track or lawn on which you run.  You estimate the
lean for the conditions and you control your speed to not exceed
that angle.  Although the consequences are more severe, the same is
true for the bicycle.

These are reflexes that are normal to most people in youth but some
have not exercised them in such a long time that they don't trust
their skills.  A single fall strongly reinforces this doubt.  For
this reason, it is best to improve and regenerate these abilities
gradually through practice.

Braking

Once the nuts and bolts of getting around a corner are in place the
big difference between being fast and being faster is another
problem entirely.  First it must be understood that braking is a
primary skill that is greatly misunderstood.  When traction is good,
the front brake should be used almost exclusively because, with it,
the bike can slow down so rapidly that the back wheel lifts off the
road.  When slowing down at this rate the rear brake is obviously
useless.  Once you enter the curve, more and more traction is used
by the lean angle but braking is still used to trim speed.  This is
done with both brakes because neither wheel has much additional
traction to give.  It is good to practice hard front braking at a
low and safe speed to develop a feel for rear wheel lift-off.

You may ask why you should be braking in the turn.  If you do all
your braking before the turn you will be going too slowly too early.
Because it is practically impossible to anticipate the exact maximum
speed for the apex of the turn, you should anticipate braking in the
turn.  Fear of braking usually comes from an incident caused by
injudicious braking.  How you use the front and rear brake must be
adapted to various conditions.  When riding straight ahead with good
traction, you can safely allow substantial transfer of weight from
the rear to the front wheel allowing strong use of the front brake.
When traction is poor, deceleration and weight transfer is small, so
light braking with both wheels is appropriate.  If traction is
miserable, you should use only the rear brake because, although a
rear skid is permissible, one in the front is not.

Take for example a rider cornering on good traction, banked over at
45 degrees.  With 1 G centrifugal acceleration, he can still apply
the brakes at 0.1 G. The increases in side force on the wheels is
given by the square root(1^2+0.1^2)=1.005.  In other words, you can
do appreciable braking while at maximum cornering.  The centrifugal
acceleration is also reduced by the square of the speed by which the
lean angle rapidly reduces.  Being aware of this relationship should
leave no doubt about why racers are often seen pulling their brake
levers in max speed turns.

Suspension

Beyond lean and braking, suspension helps immeasurably in
descending.  For bicycles without built-in suspension, this is
furnished by your legs.  If the road has fine ripples you needn't
stand up but merely take the weight off your pelvic bones.  For
rougher roads, you should rise high enough so the saddle does not
carry any weight.  The reason for this is twofold.  Your vision will
become blurred if you don't rise off the saddle, and traction will
be compromised by momentary overloads while skipping over bumps.
The ideal is to keep the tire on the ground at uniform load.

Some riders believe that sticking out their knee or leaning their
body away from the bike, improves cornering.  Sticking out a knee is
the same thing that riders without cleats do when they stick out a
foot, it is a useless but reassuring gesture that, on uneven roads,
actually works against you.  Any body weight that is not centered on
the bicycle (leaning the bike or sticking out a knee) puts a side
load on the bicycle, and side loads cause steering motions if the
road is not smooth.  To verify this, ride down a straight but rough
road standing on one pedal with the bike slanted, and note how the
bike follows an erratic course.  In contrast, if you ride centered
on the bike you can ride no-hands perfectly straight over rough
road.  When you lean off the bike you cannot ride a smooth line over
road irregularities, especially in curves.  For best control, stay
centered over your bike.

Vision

Where you look is critical to effective descending.  Your central
vision involves mostly the cones in the retina of your eye.  These
are color receptive and images generally are more time consuming to
interpret than information received by the rods in the peripheral
vision.  For this reason you should focus on the pavement where your
tire will track while looking for obstacles and possible oncoming
traffic in your peripheral vision that is fast and good at detecting
motion.  If you look at the place where an oncoming vehicle or
obstacle might appear, its appearance will bring data processing to
a halt for a substantial time.  You needn't identify the color or
model of car so leave it to the peripheral vision in high speed
black and white because processing speed is essential.

The Line

Picking the broadest curve through a corner should be obvious by the
time the preceding skills are mastered but the line is both a matter
of safety and road surface.  Sometimes it is better to hit a bump or
a "Bott's dot" than to alter the line, especially at high speed.  In
that respect, your tire should be large enough to absorb the entire
height of a "Bott's dot" without pinching the tube.

Mental Speed

Mental speed is demanded by all of these and, it is my experience,
those who are slow to grasp an idea, do not have good hand-eye
coordination, or are "accident prone", should be extra cautious in
this.  In contrast, being quick does not guarantee success either.
Above all, it is important to not be daring but rather to ride with
a margin that leaves a comfortable feeling rather than one of high
risk.  At the same time, do not be blinded by the age old
presumption that everyone who rides faster than I is crazy.  It is
one of the most common descriptions used by a slower observer.  "He
descended like a madman!" means merely that the speaker was slower,
nothing more.

Ride bike!

---------------------------------------------------------------------------

Trackstands   (Rick Smith  ricks@sdd.hp.com)

                How to trackstand on a road bike.
	
	With acknowledgments to my trackstanding mentor,
 	             Neil Bankston.

  Practice, Practice, Practice, Practice, ....

  1. Wear tennis shoes.
  2. Find an open area, like a parking lot that has a slight grade to it.
  3. Put bike in a gear around a 42-18.
  4. Ride around out of the saddle in a counter-clockwise circle, about
     10 feet in diameter.

     Label Notation for imaginary points on the circle:
       'A' is the lowest elevation point on the circle.
       'B' is the 90 degrees counterclockwise from 'A' .
       'C' is the highest elevation point on the circle.
       'D' is the 90 degrees counterclockwise from 'C' .

        C
      /   \
     D     B       Aerial View 
      \   /
        A

   5. Start slowing down, feeling the different sensation as the bike
      transitions between going uphill (B) and downhill (D).
   6. Start trying to go real slowly through the A - B region of the circle.
      This is the region you will use for trackstanding.  Ride the rest of
      the circle as you were in step 5.
   
      The trackstanding position (aerial view again):

	       ---|   /
	------| |----/
           |---     /


      The pedal are in a 3 o'clock - 9 o'clock arrangement (in other
      words, parallel to the ground).  Your left foot is forward, your
      wheel is pointed left.  You are standing and shifting you weight
      to keep balance.  The key to it all is this:

	  If you start to fall left, push on the left peddle to move the
	  bike forward a little and bring you back into balance.

	  If you start to fall right, let up on the peddle and let the
	  bike roll back a little and bring you back into balance.

    7. Each time you roll through the A - B region, try to stop when
       the left peddle is horizontal and forward.  If you start to
       lose your balance, just continue around the circle and try it
       again.

    8. Play with it.  Try doing it in various regions in the circle,
       with various foot position, and various amounts of turn in your
       steering.  Try it on different amounts of slope in the
       pavement.  Try different gears.  What you are shooting for is
       the feel that's involved, and it comes with practice.

The why's of trackstanding:

  Why is road bike specified in the title?
      A true trackstand on a track bike is done differently.  A track
      bike can be peddled backwards, and doesn't need a hill to
      accomplish the rollback affect.  Track racing trackstands
      are done opposite of what is described.  They take place on the
      C - D region of the circle, with gravity used for the roll
      forward, and back pedaling used for the rollback.  This is so
      that a racer gets the assist from gravity to get going again
      when the competition makes a move.

  Why a gear around 42-18?
      This is a reasonable middle between too small, where you would
      reach the bottom of the stroke on the roll forward, and too big,
      where you couldn't generate the roll forward force needed.

  Why is the circle counter-clockwise?
      Because I assume you are living in an area where travel is done
      on the right side of the road.  When doing trackstands on the road,
      most likely it will be at traffic lights.  Roads are crowned - higher
      in the middle, lower on the shoulders - and you use this crown as
      the uphill portion of the circle (region A-B).  If you are in a
      country where travel is done on the left side of the road,
      please interpret the above aerial views as subterranial.

  Why is this done out of the saddle?
      It's easier!!  It can be done in while seated, but you lose the
      freedom to do weight adjustments with your hips.

  Why is the left crank forward?
      If your right crank was forward, you might bump the front wheel
      with your toe.  Remember the steering is turned so that the back
      of the front wheel is on the right side of the bike.  Some bikes
      have overlap of the region where the wheel can go and your foot
      is.  Even if your current bike doesn't have overlap, it's better
      to learn the technique as described in case you are demonstrating
      your new skill on a bike that does have overlap.

  Why the A - B region?
      It's the easiest.  If you wait till the bike is around 'B', then
      you have to keep more force on the peddle to hold it still.  If
      you are around the 'A' point, there may not be enough slope to
      allow the bike to roll back.

Questions:

  What do I  do if I want to stop on a downhill?
      While there are techniques that can be employed to keep you in
      the pedals, for safety sake I would suggest getting out of the
      pedals and putting your foot down.

Other exercises that help:

    Getting good balance.  Work through this progression:
      1. Stand on your right foot.  Hold this until it feels stable.
      2. Close your eyes.  Hold this until it feels stable.
      3. Go up on your toes.  Hold this until it feels stable.
      4. If you get to here, never mind, your balance is already wonderful,
         else repeat with other foot.