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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 ...


14

Don't overthink it. Since you've got a triple, you're probably right to be in your middle ring most of the time That's normal. In the middle ring you should have access to the whole cassette/freewheel in the back, though you might get a little extra noise as you approach the extreme gears in either direction. You'll use the big chainring when you're going ...


13

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 ...


11

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 ...


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

Answers for a typical 21-speed commuter I could find specs on: 20, 19, 15, 12. 20 is the technically right answer, 19 is a slightly more technically right answer, 15 is if you take into account gears that are nearly identical, but 12 is the practical usable answer. Really, it's going to depend on your exact gear setup. At the very least, you really should ...


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

It is not necessarily "good" for your workout. If you drop into the 'easy' gear, you obviously have to pedal faster to maintain your speed. Going at a slower cadence in a higher gear will just trash your knees after awhile. Select the gear that yields a similar cadence as when you are riding on the flats, while maintaining a similar energy expenditure. ...


11

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

There's nothing wrong with doing this. It works well to shift the rear 1 or 2 shorter when shifting the front 1 taller (and vice versa) to avoid big steps in gearing.


10

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 ...


10

If you take the back wheel off you should be able to examine the freewheel/cassette to determine which it is. Here is a picture of some common types. If yours doesn't look like one in the picture, post a close up and I'm sure someone here can identify it.


9

Ultimately it's a trade-off between a wider range of gears and bigger jumps between those gears. There will always be uphills that are too steep for your lowest gear and downhills where you spin out. If you try to fix both problems with a wider range cassette (your triple already has a great range) you may find that you're never quite in the "right" gear ...


9

Excluding the two extremes (see Scott Robinson's answer), you have 19 ratios. Some of these may be very close to each other. The easiest way (although a little cumbersome) is to count the number of teeth (n) on all gears (three in front, seven rear) counting from the centerline of the bike (outwards). The ratio is given as n(front) / n(rear), e.g.: 1st = ...


9

You may need to adjust your derailer limit stops (see here).


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

A stretched chain will wear out gears (especially the rear cassette). You can see when this because the teeth get worn away to points - it's very obvious. But it's very unlikely you wore out a chain and gears in 1000 Km. What is more likely is that the cable has stretched slight from new and the derailuer is out of adjustment so it is putting the chain ...


9

No. The full gearing ratio of the bike (from your foot to the tire contact patch) is determined by four factors: the crank length, the chainring diameter, the cog diameter and the wheel diameter. Since these components can be changed independently, it is impossible to develop a uniform numbering system for a single component ("uniform" in this case means ...


9

Replacing a hub is not a "simple" procedure -- it, at a minimum, involves relacing the rear wheel, probably with different sized spokes (whose size you must accurately determine). Relacing is not beyond the abilities of a competent backyard mechanic, but is a skill that needs to be learned. To add a second chainring you must install some sort of device to ...


9

Assuming you have Shimano-compatiple Hyperglide cogs: No, you can't. The cassette body is not symmetric, the cassette fits in only one position. You could resort to adapt the cogs with a file, though. But shifting will be problematic at least, the cogs have certain indents to make shifting smoother.


9

The main hindrance will be actually getting going from a standstill. This kind of thing has been done quite a bit and is called motor-pacing and involves riding a very highly geared (usually fixed-gear) bike behind a fast car with some kind of fairing to reduce wind resistance on the bike. Speeds of well over 100mph have been reached. This kind of bike is ...


8

Gearing is commonly described in Gear Inches and to clarify, having your chain in the smallest front ring and the biggest rear cog results in the smallest gear. Chainrings The smallest chainring I've seen on a 5-arm crankset is a 20T, although 24T is a lot more common. 8-Speed cassettes Shimano had a line called "Megarange" that was 11-34T. I believe ...


8

Put the chain around the big-big gears without threading it through the derailleur. Have the chain overlap by one link. Now with that length thread it through the derailleur. http://sheldonbrown.com/derailer-adjustment.html#chain


8

Depending on the tension of the chain, you might be slightly more likely to jump, e.g. going from big to little on both front and back at the same time is increasing the slack in the chain and moving it in both directions (front to the left, back to the right). So depending on the timing, not only will the slack need to be damped out and the indexing might ...


8

The simple answer is, no, it is not advisable, and yes it can cause damage. The chain uses tension to shift. Shifting with both front and rear derailleurs at the same time will remove that tension. The answer above is absolutely correct, but they are a bit too phlegmatic about the risks involved. Drop a chain due to poor shifting habits, and you risk ...


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

I think everyone has provided some pretty sound advice, especially Daniel Hicks and his recommendation to go with the quickest and cost effective option by replacing your chainrings! With a 130/74 BCD, an ideal setup would be to swap in a 24/36/48 which would give you a great range at a cheap price. The front derailleur is probably the least necessary ...


8

The problem is that any rear cluster designed for indexed shifting has directional cogs. There are ramps embossed on the sides of the cogs to catch the chain pins and lever the chain up to the next larger cog when the chain is shifted. If you somehow reverse the cogs these ramps will be on the wrong side of the cogs and will be running the wrong direction. ...



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