Questions tagged [derailleur]
Mechanism to move the chain from one sprocket to another.
98
questions
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6
answers
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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 ...
- 7,846
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votes
2
answers
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Moving from 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. But ...
- 9,753
9
votes
3
answers
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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 ...
- 1,478
11
votes
3
answers
39k
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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 ...
- 6,273
49
votes
11
answers
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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?
- 2,908
15
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3
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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.
- 4,352
13
votes
2
answers
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Bike chain slips in a strange way
I bought a new bike about a month ago. And it made a strange sound from the first ride , I thought the sound was because it was new and will disappear with time but it didn't. The sound is like a ...
- 133
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3
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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 ...
user1480
6
votes
3
answers
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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 ...
- 18.8k
5
votes
2
answers
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(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 ...
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4
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3
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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 ...
- 7,846
38
votes
5
answers
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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 ...
- 481
18
votes
2
answers
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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 ...
- 8,619
15
votes
2
answers
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Is there a downside to spoke protectors?
A few weeks ago, the derailer on my touring bike caught on the chain and ripped itself off the frame. (See the link below for more info on the incident.) The spoke protector was cracked in half by ...
15
votes
6
answers
80k
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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 ...
- 910
13
votes
1
answer
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Selecting a front derailleur: parameters
The spec sheet for the Shimano Alivio FD-M430 front derailleur contains a number of points that I don't understand.
What does "Maximum capacity: 22 teeth" mean?
Why are "Top gear teeth" constrained ...
- 13.9k
10
votes
7
answers
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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 ...
- 1,705
9
votes
7
answers
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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 ...
- 221
8
votes
4
answers
39k
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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 ...
- 18.3k
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answers
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Chain cassette noise
Hello fellow cyclists,
I just bought a new Home Trainer that has a Shimano 105 Cassette.
My Bike has an Ultegra drivetrain with less than 600km (375mi).
I have checked the wear of the chain which ...
- 91
7
votes
3
answers
2k
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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 ...
- 13.9k
6
votes
4
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Are the Shimano derailleurs sold on Ali Express genuine or fake?
I am trying to buy Shimano Alivio M4000 components. When I was researching on Ali Express, I found this. This is Alivio M4000 including the front derailleur, rear derailleur, left and right Shifters ...
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6
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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?
- 163
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votes
1
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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....
- 53
3
votes
3
answers
382
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 ...
- 133
3
votes
1
answer
8k
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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?
- 305
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votes
1
answer
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Shimano RD-R7000 cable cut into thread?
That gap/cut in the hollow screw of the cable mount is not supposed
to be there, right?
If so, is this a typical defect?
The hollow screw is pressed into the derailleur
body and not replaceable, so ...
2
votes
2
answers
3k
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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 ...
- 531
2
votes
3
answers
483
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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 ...
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1
vote
3
answers
8k
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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 ...
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