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24

The first rule is make sure the rear derailleur is adjusted correctly before adjusting the front derailleur. There are three adjustments that you can do on the front derailleur: Clamp Position Low limit stop High limit stop Clamp Position Here you can adjust the height of the derailleur, normally this is recommended as a 2mm clearance between the ...


16

A lot depends on the rider and what you mean by efficiency. It is easy to keep a hub gear running well for years, but an unmaintained derailleur will become inefficient very quickly. A hub gear allows the chain to be fully enclosed, for all but the most dedicated cyclist; an enclosed chain will be more efficient as it will be cleaner and better oiled. An ...


15

I've put a red circle around the hanger bolt.


12

I don't have an internal hub, but I want one for the following reasons: They are sealed and protected from the elements. They are nice for commuting because you can shift them while stopped... If you've ever stopped at a red light on a normal bike and struggled to get going again because of your gear, you can appreciate this. With an Internal hub, you can ...


12

Jan Heine performed some wind tunnel tests of "Real World Aerodynamics" a few years ago. A link to a blog post (and the results published in Bicycle Quarterly) can be found here. Those tests cover only one component (the aero drag component) of commuter-type bicycles vs. "racing" bikes. If you want to make your own apples-to-apples comparisons of ...


11

It depends on the model you get, but the efficiency is generally comparable. Derailleurs that are in really good condition and properly lubed will be more efficient, but marginally, and will often be less efficient due to real world conditions. At least that's what the wiki says: http://en.wikipedia.org/wiki/Hub_gear I have one road bike with a 3x9 ...


11

If you are asking how to calculate the maximum capacity of the chainrings and cogs, based on looking at the derailleur, then it's not going to be as easy as just looking at them. Finding a derailleur to fit your chainrings/cogs based on just the chainrings/cogs is going to be a lot easier than finding chainrings based on looking at your derailleur. HOWEVER, ...


11

A front derailer is a bit more complicated than it looks, and can be quite complex to adjust if you're starting from zero -- just having installed the unit. There are five (and a half) adjustments -- Height, sliding up and down the seat tube. Rotation around the seat tube. Low limit High limit Cable tightness Generally height is such that the derailer, ...


11

If you can, with the chain in one of the middle cogs in the back, shift to each of the front chain rings then your front derailleur is likely in proper alignment and adjustment. This question and answer cover how to adjust the derailleur if you want to learn how to do it yourself. What you are describing, shifting to small ring in front and small cog in ...


11

Yes, there is a difference between front chainrings for derailleur equipped bikes compared to bikes without a derailleur. Basically a derailleur suitable chainring "wants" to fall off. It's designed so that the chain is happy to climb onto the gear and also fall off the gear. There are various ramps for the chain to engage into. Non-derailleur chainrings ...


11

For the same reason you can't have a fixie with a chain tensioner. The load on the chain when slowing a fixie is too great and in the wrong direction for a derailler or tensioner to hold. The cage will be pulled forward and your chain will skip make a nasty noise and most likely come off or break something expensive.


10

In 2001, Kyle and Berto published a comparison of the mechanical efficiency of several configurations of derailleur and internally-geared hubs in Human Power, which you can find here. Among the systems tested were a Shimano MTB derailleur system, a Sturmey-Archer 3-speed hub, the Shimano 7-speed Nexus hub, and the 14-speed Rohloff hub. MTB derailleur systems ...


10

There is no 'conspiracy' to keep friction shifters off the market just so that you have to buy the index shifters. It is simply a matter of supply and demand. Nobody in the OEM market wants friction shift gears because bikes with friction-shift simply do not sell. That leaves the after-market and you have a similar position there - the demand does not exist ...


10

Well I thought we needed an answer to this, so I just phoned the shop. He's a nice fellow (as you can tell from the vid) and said that his mechanic is convinced that this method works to free-up seized and corroded mechs. Apparently dousing it in something like GT85 and lighting it for a very short time boils in the lube, and works. I assume that the ...


10

20,000km's in 2 years on Ultegra Di2. It performs very well. Shifts are smooth, crisp, quick and effortless. I have a few other road bikes running various mechanical shifters, but have preferred the electronic shifters during the past two years. No need for adjustment due to no more cable stretch. The front derailleur auto trims and follows the rear ...


10

This is an odd question. The sentiment that the only security here is physical security is correct. Think about the following: The Shimano Di2 components are not mated/matched to a specific computer or instance of E-Tube software. So there's no 1:1 relationship. Therefore, any computer equipped with the SM-PCE1 or SM-BCR2 programming cables can be used to ...


9

There are a number of reasons that the shifting on your rear derailleur is not working well: The derailleur hanger (the bit of the frame that the derailleur bolts onto) could be bent. To check this look at the angle that the derailleur cage is at. When viewed from behind, it should be vertical, when viewed from above, it should be parallel to the ...


9

Worn derailleur pulleys (also known as "jockey wheels") will not cause excessive wear on a chain because they aren't made of metal. Eventually, though, the bushings inside will become worn and the outer teeth will wear down. Park illustrates the latter progression in their article on rear derailleur overhaul. As with many things in bicycle maintenance the ...


9

This type of problem has 5 likely causes, listed in order of elimination. Bent dérailleur hanger, or Bent derailleur cage. (Your derailleur hanger looks straight, but the cage appears slightly twisted in the upper photo. Could be the angle of the shot, though.) Edit: This turned out to be the correct answer, after all. Bent, twisted, or sticky chain link. ...


9

The spacing between 9 speed and 10 speed is controlled at the shift lever. A 10 speed rear dérailleur will work with a 9 or 10 speed cassette and shifter. A 9 speed rear dérailleur is not compatible with 10 speed. The width of the chain and the cogs is the biggest issue. The pulleys on a 10 speed dérailleur are narrower, and a 10 speed chain will not rest ...


9

http://www.landriderbikes.com They were very heavily advertised several years ago but currently they seem to show up more on craigslist than on TV.


8

If your derailleur is adjusted properly, and you are slipping gears, it's usually a worn chain and rear cog. Take the bike into your local bike shop, and they can help you get replacements.


8

No, you will need to get a whole new cassette, the largest 3 rings are connected to each other, you cannot just purchase individual cogs. You may want to get a new chain as you will probably need to make a chain length change with jumping from a 25T to 27T or 28T largest cog. Do you know if you have the SS or the GS? With the SS (short cage) you can go as ...


8

Typically you quote gear sizes in gear inches, very basically this is the drive wheel diameter multiplied by the ratio between the two gear cogs, traditionally quoted in inches. Also sometimes mentioned is development which is the amount of distance travelled by one revolution of the cranks (the astute will notice that is going to be proportional to gear ...


8

If the teeth on the jockey wheels appear to be in good shape then you probably have nothing to worry about. Many jockey wheels use bushings instead of bearings, and either way they are not going to spin for very long just because there's not much weight to them and therefore they don't carry much inertia. If there is noticeable resistance when you try to ...


7

There's not much you can do aside from cleaning your drivetrain often and thoroughly. In the winter, ice is far less of a mechanical issue than is rock salt. You may indeed have some corrosion in the entire drivetrain by this point, not just the deraileur, or possibly just dirt if you're lucky. I'd do one major cleaning at this point, and see if that takes ...


7

Adjusting the rear derailleur is a matter of tightening or slackening the shifter cable so that the chain runs smoothly for all rear cogs. The easiest way to do this is using a barrel adjuster -- there's normally one where the cable runs into the derailleur and you may have another where the cable runs into the shifter or on the downtube for a road bike. ...


7

Did you change the chain after the first derailleur broke? If the same chain was on and you're positive the derailleur didn't connect with the spokes, then the chain is a likely culprit. Another thing to watch out for is loose pannier straps (or anything else that could get caught in the chain and take out the derailleur).


7

Neil is right, most all "auto shifting" or "ghost shifting" is the result of cable-tension problems. If the cable is a bit loose, the derailleur will try to shift "up" to a smaller cog. If too tight, it will try to catch the next larger cog. Cables stretch, especially after a short period where the new cables stretch to the point they're stable. after ...



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