Talk:Hub gear

message: Not having understood too much about hub/epicyclic gears until today, I'd appreciate some feedback on the diagram I've added. As I understand it, there are several different ways of driving the gearing system, involving various configurations of fixed parts and movable parts. Some that I looked at had a fixed sun gear, and movable planetary gear holder that provided the input rotation; I don't know which is more common.
A good explanation of how gearing ratios are determined in this sytem would be nice to have! Also, if anyone can point me to some good diagrams of how an epicyclic gearbox or transmission (with multiple ratios) works, I can think about making a diagram of that too. -- Wapcaplet 03:25, 14 Nov 2003 (UTC)
replies: text: Unfortunately this shows a turning sun gear - in all bicycle gear hubs, the sun stays still (being keyed to the axle) while the gear ring and planet cage rotate.  —Preceding unsigned comment added by 62.249.214.190 (talk) 18:23, 21 November 2008 (UTC)
replies: text: A better diagram wanted but it must be copy-right free. MalcolmMcDonald (talk) 19:17, 3 February 2010 (UTC)

text: I believe this is finally sorted out according to the description given by Sheldon Brown. -AndrewDressel (talk) 15:41, 21 November 2011 (UTC)
thread_title:  Image 

message: It seems rather strange to make such broad claims about the usage in different regions of the world. They should at least be substantiated by an independent source. Bfg 12:01, 5 July 2006 (UTC)
replies: text: Also, first it says derailleur gears are most common in the UK and US while hub gears are more common in continental Europe. But a bit further it says derailleur gears have since the 1950's become the most common type of gear system on bicycles. But I imagine that in other parts of the world they are very uncommon. Or is it that there, no gears are the most common thing? It seems too strong a statement, so I'll tone it down a bit. DirkvdM 07:25, 2 August 2006 (UTC)
thread_title:  Usage in USA/UK - Continental Europe and the World

message: I know the cutaway image of the 14-speed hub is fantastically fascinating and beautful, but such intricate and recently developed mechanisms are almost unheard of in practice. Might it be better to find a similar image of something more illustrative of hub gears commonly used by cyclists (3-speed, probably), rather than a rather baffling mechanical curiosity? Ninly 17:31, 11 August 2006 (UTC)
thread_title:  Image/Illustration 

message: Toyota is using an adaptation of this for its toyota prius electronic continuously variable transmission. At least the gears look similar even though the purpose and use are very different. Check out this site. 
[Prius\http://www.ecrostech.com/prius/original/PriusFrames.htm] - Go to Understanding -> power split device. Might deserve a mention. —The preceding unsigned comment was added by Chathu50 (talk • contribs) 09:02, 9 May 2007 (UTC)
thread_title:  Other Uses 

message: Someone's confused the advantages/disadvantages section recently by replacing an item stating that hub gears are heavier with one stating that they are not, and that they cost around the same as derailleurs, but leaving it under Disadvantages. As it's currently worded, it's a neutral statement, and I don't know enough about gears to say whether it's right or wrong.
:I think I've fixed that. Hub-gears are heavier and more expensive. MalcolmMcDonald (talk) 19:17, 3 February 2010 (UTC)
replies: text: In general one can say that derailleurs are more efficient but that's not going to be emphasised in an article about hub-gears because it doesn't concern the cycling of most users. It might be more to significant to the users of hub-gears with large numbers of gears. With some exceptions and running conditions as mentioned. MalcolmMcDonald (talk) 19:17, 3 February 2010 (UTC)
thread_title:  Confusing Advantages/disadvantages 

message: I changed the item in the disadvantages section; I think it should really discuss to repair rather than maintenance.
As noted in the advantages section hub gears have very minimal maintenance, most are sealed for life (without even oil or grease points) and the only real maintenance you can do is adjusting and replacing the actuator cable, and possibly renewing the gear cog.
But if they fail (and that's a big 'if') you cannot easily get spares or dismantle them, and wholesale replacement is normally the only option. Whereas you can pick up individual components of a dérailleur in any decent bike shop when (not 'if') it becomes badly worn or fails.
:Gear hubs aren't sealed for life, all of them can be opened and re-greased. Sturmey-Archer ones have a screw in ball bearing recess that is hard to get loose after years of use. Other brands usually use a large bearing that leaves a hole big enough to allow the internals in as a whole. Only the Rohloff hub uses press-fit bearing witch are difficult (but unnecessary, due to an alternative way of lubrication) to remove. Maintenance hardly ever happens though, because the are usually owned by people that just use them for basic transportation.
:When gear hubs fail it is usually an indirect consequence of lubrication starvation. Every brand had its own flaws.
:Sturmey-Archer ones usually fail due to one of the pawls losing function creating an uneven load on the system or breaking internal toothings due to incomplete engagements of the pawls. Even so, most survive this severe condition unnoticed for quite a while. Some have been known to be prone to axle breakage (they were made in the 80s and the beginning of the 90s (exact dates are hard to find) I have seen some for myself, the exact failure mechanism is unknown to me, the axles appear unaffected by corrosion).
:Sachs ones are known to be quite reliable (except the Elan version, but it can be considered a one-off), most problems come from bearing rings that break after a while. Usually replacing the bearing rings with loose balls (and removing the debris) solves the problem. The grease in them can dry similar to the Sturmey-Archer ones, usually this causes internal springs to lock onto moving parts and getting jammed in the mechanism, usually just disrupting gear function. These can usually be replaced and gear function restored.
:Shimano has been known for problems with the outer bearing getting contaminated with water and getting rusted and consequently pitted, even after a limited amount of time in wet environments. When detected in time this bearing can be replaced and re-greased. If not, the bearings will usually come loose of the worn bearing rings and block parts of the mechanism. The mechanism itself usually suffers little, but the bearing recesses are of little use by then and cannot be replaced in most hubs. Oil-lubrication has been recommended for these hubs by some, but to my knowledge no long term data of its workings have been published. Shimano has introduced a maintenance routine to replenish the internal grease with a special kind of maintenance oil. The recommended maintenance interval is relatively short and unknown to most repair shops, while the oil itself is quite expensive for individual use so this routine is quite unique.
:Significant wear is unlikely even when lubricated only reasonably well due to the low rotational speed of bikes. Torque-induced damage is uncommon and unlikely to be caused by lack of maintenance. 82.139.114.136 (talk) 11:46, 28 June 2012 (UTC)
thread_title:  Maintenance vs repair 

message: This table contains wrong values and different configurations. No sources are indicated.
The weight of the SG-700 appears to be 1744 g Review. 1600 g was a target that was never met. 
The weight of the Speedhub is 1700 g in the standard configuration, and 1825 g  in the configuration for disc brakes.
Please correct the values, indicate the various configuration, and indicate the sources of the data. Thanks.  — Preceding unsigned comment added by Bogl4712 (talk • contribs) 19:51, 14 June 2011 (UTC)
replies: text: Your link/reference does not work. Do you have one that works? Keanu (talk) 21:36, 14 June 2011 (UTC)
thread_title:  Hub Weight Comparison (in table in section "List of multispeed hub gears") 

message: Possibly move the second paragraph to  Latest Developments, Hub-gears in everyday use, or History sections, it seems to be in an odd place that makes the into seem disjointed.
Also adding Minneapolis (https://www.niceridemn.org) and B-Cycle locations (http://www.bcycle.com)  — Preceding unsigned comment added by 71.37.226.17 (talk) 19:14, 22 June 2011 (UTC)
thread_title:   Re-Organizing/ moving second paragraph in intro 

message: The following has been removed: "Hub gears can be simpler to use for inexperienced riders, because there is generally only a single shifter to operate and there are no overlapping gear ratios. By contrast, modern derailleur systems often have two shifters, and require some forethought to avoid problematic gear combinations." I believe this to be an advantage over front and rear derailleur geared bikes with a right and a left shifter with two operation directions each, as the rider has to operate up to four trigger shift levers with opposing gear ratio changes on the right and left side to ensure that the chainline is kept relatively level. The trigger finger typically shifts to a lower gear ratio on the left side shifter while the trigger finger shifts to a higher gear ratio on the right side shifter. It is a problem mostly with wide gear range derailleur gear systems, with two or more chainrings up front. Please help modify the above sentence so that it better explains this factor or I will simply reenter it. Keanu (talk) 11:53, 5 February 2013 (UTC)
thread_title: Simplicity of shifting