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Questions tagged [derailleur]

Mechanism to move the chain from one sprocket to another.

10
votes
2answers
16k views

Moving tfrom Shimano 9- to Shimano 10- speed

I'm thinking of changing the 9-speed Tiagra rear mech on one of my (road) bikes to something, still Shimano, but 10-speed. The obvious replacements I'll need are cassette, right-shifter and chain. ...
22
votes
5answers
130k views

How to calculate the capacity of a rear derailleur

It's easy to calculate what capacity of a rear derailleur will be needed based on the size of the big and small chainring and the big and small cog. What about the converse question, how to calculate ...
8
votes
3answers
12k views

Road Shifters, Mountain Rear Derailleur?

I have a road/cyclocross/commuter frame that is currently spec'd with road components - all Shimano 105, with an Ultegra rear derailleur. The cassette (10 spd) tops out at 27 teeth, and the rear ...
9
votes
3answers
31k views

How do I adjust my rear derailleur (Shimano SIS) when it is only slightly out?

It has been a while since I had my bike serviced and the gears are sometimes slightly out of perfect alignment. This results in the occasional mis-shift. I also think the change in seasons have ...
4
votes
3answers
46k views

Determining which derailleur hanger is compatible with a frame

When your derailleur hanger needs replacing, is there a good resource for matching frames to hangers? Mine was recently bent, so I had to dig through some websites and compare pictures of the hangers ...
6
votes
3answers
8k views

Does a rear derailleur guard provide effective protection?

I recently caught my rear derailleur on a log and snapped it in two. I have done some recent work on some department store bikes and noticed that some come equipped with an axle mounted guard around ...
3
votes
3answers
31k views

Front derailleur won't spring back to lower gears

The front derailleur on my mountainbike sometimes gets stuck in high gears. When this happens and I want to shift down I can nudge it a bit with my foot and it will spring back to the lower gear. I ...
34
votes
5answers
11k views

Perfectly setting up gears - how?

Every time I have my bike serviced, the bike shop sets up the gears on a stand in their workshop. The gears change perfectly on the stand, but when the bike is on the road, the rear derailleur doesn't ...
9
votes
7answers
64k views

Problem with chain skipping without trying to shift (even with new chain and gears)

I have a mountain bike where the chain intermittently skips when put under load on the middle (and very rarely on the smallest) chain ring. It is not related to shifting. I've taken several steps to ...
14
votes
2answers
28k views

Chain slipping off derailleur jockey

Last week, I had to abandon a training ride due to my chain slipping off my rear derailleur jockey wheel. This would only happen when shifting, and most often when either shifting chainrings or ...
9
votes
3answers
36k views

Is my chain too long?

I'm in the process of setting up a new drive train. When using the smaller chainring and smallest sprocket (hence least amount of utilized chain), the chain brushes up against the bottom of the ...
12
votes
5answers
36k views

Bike is shifting on its own

Ever since I got my bike (Surly Long Haul Trucker), it has been prone to shifting on its own. This is almost guaranteed to happen when I stand up on the pedals, and happens regularly when sitting as ...
11
votes
3answers
51k views

How can you identify if a Shimano rear derailleur is medium or long cage?

I have a 2013 Shimano XT rear derailleur. It is part of a 2x10 drivetrain. How can I find out if it is a medium or a long cage one? The picture below shows the derailleur.
6
votes
3answers
2k views

What are the most common causes for hysteresis in the rear derailler?

I have often seen derailleurs on cheap MTBs to degrade in performance by showing hysteresis. By that I mean that to switch to a certain cog, one needs to shift one cog further and then immediately one ...
6
votes
2answers
2k views

is this derailleur short cage or long cage?

I'm selling the rear derailleur off this bike, and someone asked whether it's short or long cage. I assume it's long. Is this correct?
5
votes
2answers
2k views

(Automatic Bike Project) amount of torque required to change gears?

I am planning to build an electronically controlled automatic bike transmission for my senior design project. I'm personally more of an electrical guy, so dealing with the mechanics is somewhat new to ...
3
votes
3answers
367 views

Gear shift adjustments

I recently had to replace the shifters on my bike. The replacement was easy enough, but now when I shift the derailleur either jumps too far or too short. I've tried using the adjustment screws on the ...
1
vote
3answers
4k views

Can't shift to gear one or two

I had an issue where every time I put my bike in gear 3, it would just keep "skipping". By this I mean that it wouldn't stay in gear 3; the chain would go onto it, then fall onto gear 4, then go back ...
9
votes
6answers
55k views

Can a road bike's rear derailleur be used for either a 9 speed cassette or 10 speed cassette?

I currently have a 9 speed 11-25T cassette on my road bike. I'm thinking about switching to a different cassette with more teeth on the climbing gear. The cassette I'm currently look at is a Shimano ...
7
votes
4answers
29k views

Can I fit a cassette with a larger range with my Shimano Tiagra 10-speed ( GS-4600) derailleur?

I'm currently running a 2x10 shimano tiagra 10-speed drivetrain with a 50/34 compact crankset, a 12-30 rear cassette, and a Shimano Tiagra GS-4600 derailleur (that's medium cage aka road long cage) on ...
3
votes
1answer
3k views

Converting a short cage rear derailleur to a long cage derailleur

Is it possible to convert a short cage rear derailleur (for example the Huret Svelto) to a long cage derailleur by just taking the lower cage and replacing it by a longer one?
2
votes
1answer
4k views

Replaced Shimano Bottom Bracket, now front derailleur won't shift to largest gear

OK, so in my quest to get my old Trek 7000 ZX MTB running again after a long retirement, I am having an issue with replacing the bottom bracket. The bike came with a Shimano LP25 that is marked BC 1....
2
votes
3answers
266 views

Why does my front derailleur not work when it is cold?

When it is warm outside my front derailleur works just fine. But when it gets colder (40F) the lever on the handle bar does not catch and I can move it without any resistance the whole way without the ...
2
votes
2answers
2k views

Road Front Derailleur / Shifter Tuning

I've recently converted into 2spd crankset so I've bought a new 2spd road lever. I'm really struggling now to tune the front derailleur. Could you please assist me by answering this questions: Why ...
0
votes
3answers
612 views

gears overshifting issue

As I have explained in my previous post here I have changed my rear shifter cable and housing. But I'm still having issues with shifting gears smoothly. It overshifts at particular gear combinations ...
48
votes
5answers
90k views

What are the pros and cons of internal gears?

I've had my hybrid 24-speed for a bit over 3 years now, and just last weekend, when looking for a bike for my wife, discovered internal gears. Suffice to say it blew my mind when I saw 7-speed ...
40
votes
10answers
21k views

What's the efficiency of hub gears compared to derailleurs?

What's the efficiency of hub gears compared to derailleurs? I know that hub gears are not as efficient. Apart from being heavier, how much will I lose in performance if I use hub gears?
19
votes
1answer
2k views

Relative efficiency of different commute bike setups

My interest is in long distance commuting (e.g. more than 50 km a day) and the relative efficiencies of different commute bike setups (e.g. drop bars vs flat bars, fenders vs no fenders, panniers vs ...
3
votes
1answer
9k views

Which derailleur should I use with a Shimano 7 speed freewheel 14-34T megarange?

Which derailleur should I use with a Shimano 7 speed freewheel 14-34T megarange in order to prevent the derailleur from rubbing the cassette in 2nd.
3
votes
3answers
11k views

Front derailleur doesn't seem to be moving

I'm trying to troubleshoot my 24 speed hybrid bike. As it was, the front shifter was having very little effect. I would change gears and not much would happen. When I had a chance to look at it, I ...
3
votes
1answer
1k views

How do I properly adjust a front derailleur?

I have a Shimano FD-TX50. How should I adjust it?
14
votes
7answers
7k views

If a derailleur cable snaps on a long ride, how can I keep going?

A couple weeks ago I rode around Crater Lake, a 35 mile ride with over 4500 feet of cumulative elevation gain – the sort of ride you really want functional gears for. The night before my rear ...
7
votes
1answer
1k views

Can't push lever to shift into big ring, lever will not move all the way

I just installed a new 6800 groupset on my bike for the first time, and everything went O.K except for the front derailleur. I can't shift it into the big ring, if I push the lever to change to the ...
7
votes
1answer
19k views

Which pulley is which on my Shimano STX RC derailleur?

I disassembled my rear derailleur to clean it; when I removed the sprockets they basically looked the same; both jet black and caked with all sorts of black grease-like-stuff. I figured they were the ...
6
votes
2answers
5k views

Is it practical to replace two sprockets on a cassette?

My bike has 53/39T chainrings and a cassette with 12,13,14,15,17,19,21,23,25 sprockets, but I like to ride up steep mountain roads. Is it possible (without great expense) to replace two sprockets to ...
6
votes
4answers
2k views

Comparing gear ratios on different bike types

How can I compare gear ratios on different wheel sizes? How can I compare gear ratios on MTB with tracking bikes with bigger wheels? How can I compare gear ratios with gear hubs?
6
votes
3answers
3k views

How can I increase the highest gear ratio?

I am looking for some higher cog front gears for an old bike I am considering. I've been away from it for some time and don't know the current number of cogs on the front ring, but I am looking to ...
5
votes
3answers
777 views

How to make a derailleur work in opposite directions?

I am making a bike for a school project that can switch between upright and pseudo-prone position. It has two sets of crank assembly; one on one side of the rear gear set and one on the other; the ...
4
votes
3answers
3k views

How do I tune up the shifters/derailleurs on my mountain bike?

I have a Diamondback mountain bike with Shimano shifters that I bought used last summer, and over time the shifting has gone out of whack. For example, on the front wheel I can't shift into the ...
4
votes
1answer
8k views

Upgrade Shimano Sora shifters to 105

I want to upgrade my 3x9 Sora shifters to 3x10 105s. However, looking at the Shimano Compatibility Chart, it appears to indicate that I'll have to replace my front and rear derailleurs in addition to ...
3
votes
1answer
5k views

9 Speed Road STI + MTB Derailleur

Apologies if this is is obvious or has been answered before. I'm looking at setting up a touring bike, using road STI levers (Shimano or equivalent, looking at Tiagra 3x9 or possibly the Microshift ...
3
votes
3answers
9k views

Is there any functional point of using alloy jockey wheels?

Jockey wheels seem like the most pointless thing to upgrade on a bike. I can see swapping out the usual grey ceramic jockey wheels for an anodized alloy one to match the look of the rest of the bike, ...
3
votes
1answer
3k views

How can I adjust index shifter so it doesn't skip the second chainring?

I recently replaced my chain and cassette on my commuter bike. It was a first time operation for me, as I am a new to doing bike maintenance. That part seems to have gone fine. While I was at it, I ...
3
votes
3answers
3k views

What causes my chain to derail at the rear when I accelerate?

I recently bought a beat-up old mountain bike for commuting. I've tried to clean and adjust the derailleurs and everything seems to work well enough in my garage. But when I put heavy weight on the ...
3
votes
3answers
517 views

Can I put a lower geared cassette on my bike?

I bought a bike recently that has a 34 front 28 rear gear ratio. It is an Elfama E2500, which is a Korean brand I believe. It has a Shimano Claris (which is rated for up to 32 teeth) rear derailleur ...
2
votes
3answers
765 views

Why does my rear derailleur's indexing work for either the high or the low gears, but not both?

I am adjusting my rear derailleur indexing. It seems impossible to find the correct tightness. When I tighten the tension with the tension barrel adjuster, I have one of two problems: either it is too ...
2
votes
1answer
346 views

Play in Jockey wheels Sram X7 rear derailleur

I have an SRAM x7 rear derailleur only been using it a few months (through the rain) and the jockey wheels seem in a bad way. There's a lot of side to side play in them and the teeth look sharp when i ...
2
votes
1answer
1k views

9sp/10sp compatibility in Shimano SLX drivetrains

This is related to my previous question about SLX chainrings. I'm half way through upgrading my drivetrain from 2x9 to 2x10. I currently have: Shifters: SL-M670-I (10sp), Chainset: FC-M665 (9sp ...
2
votes
1answer
839 views

Shimano front derailleur - tensioning, can't move shifter

I am trying to fix the front shifting on a bike (not my own, family member). The original reported problems were inability to shift into 3 (largest), combined with a tendency for the chain to come off ...
1
vote
1answer
9k views

How to setup triple front derailleur with a double crankset

I want to use my front derailleur which is a tiagra on a 3x10 speed setup with a compact double crankset making it a 2x10 setup. What is the proper procedure for setting up the triple chainring ...