Questions tagged [derailleur]
Mechanism to move the chain from one sprocket to another.
757
questions
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6
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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 ...
- 817
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?
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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 ...
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votes
13
answers
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Is there such thing as an automatic transmission for bikes?
Has anyone ever designed or manufactured an automatic transmission (or automatic shifter?) for cycling?
I imagine such a device would automatically change the gearing to allow the rider to maintain ...
- 1,321
27
votes
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
27
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6
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Why has indexed shifting displaced traditional friction shifting?
I really don't like indexed shifters, at least on the front. They're harder to adjust, more sensitive to cable stretching, and limit the number of gear combinations you can use (because you can't ...
- 1,316
26
votes
11
answers
9k
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Are there real-life alternatives to the chain+derailleur combo?
I was reading an article about the CeramicSpeed’s Driven concept and, while not interested in the efficiency part, the chainless system reminded me of something I was wondering for some time: are ...
- 1,135
19
votes
3
answers
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Is it normal for my derailleur cables to cross over on the down tube?
I've just picked myself up a Specialized Allez Sport 2014 road bike from Evans Cycles (UK).
I test rode the bike and I'm happy with the bike, but when I got home, and flipped the bike over to make a ...
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19
votes
1
answer
2k
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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 ...
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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 ...
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18
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When to change derailleur pulleys?
A friend said me that if you have one part in a very bad condition like a cassette and then you put a new stuff like a new chain it will destroy the new stuff very quickly. A LBS said that I should ...
user652
16
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4
answers
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How do I prevent the rear derailleur from slipping gears?
What's the best way to tune the rear derailleur of my bike to stop slipping gears? It seems that every time I re-adjust it, the middle/upper gears are perfectly aligned, but the lower gears never ...
- 2,075
15
votes
10
answers
5k
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Beginner breaks rear derailleur, what might have gone wrong?
I broke the rear derailleur on a borrowed bike. I'm trying to understand why.
Until two months ago I knew nothing about bicycles. I bought a worn down cheap second hand bike. It took me way more time ...
15
votes
8
answers
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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 ...
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15
votes
4
answers
21k
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What options do I have if my rear derailleur breaks when I'm out on a trail?
I ran into an unfortunate situation earlier this week. I was out on a mountain bike trail, alone — just me and my hardtail. I'm pedaling, when I suddenly hear a CRUNCH and my bike stops. The hanger ...
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3
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How efficient is string bike? Is this really a revolutionary bike?
Bicycles are getting evolved with good technologies or methodologies as the period changes. Now, this one bike, so called string bike has been introduced, which doesn't have chain, derailleur but ...
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4
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Why are derailleur jockey wheels commonly made of nylon?
Almost all derailleurs seem to come from the factory with nylon jockey wheels . What is the rationale for the use of nylon (rather than alloy or aluminum)? Is it merely weight savings (which would ...
- 29.3k
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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 ...
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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.
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2
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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 ...
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7
answers
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Is it worth buying a high end light bike (8.5 kg) from 80' vs recent mid range bike (10kg)
I want to acquire my first road bike with a limited budget (~400€) but I'm faced with a lot of choices, found an old vitus 979 equiped with campagnolo chorus, a little rusty but really pretty and ...
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Mechanic says not to use top three/bottom two gears or the chain will throw
I just bought a BTwin Fit 5, all stock, fresh from the distributor, Decathlon. Took it for light pacing at the store and things seemed OK. About 100 metres out the door, I shift up to the top end of ...
14
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1
answer
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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 ...
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13
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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 ...
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13
votes
1
answer
9k
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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 ...
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12
votes
6
answers
3k
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Ultegra RD-R8000 derailleur chewing up shifter cable - WTH?
I have an Ultegra RD-R8000 (GS cage) that has chewed up multiple shifter cables (Dura Ace and Jagwire) at the cable bolt. Seems that when in a high gear (11t chainring) the cable bends over the clamp ...
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12
votes
3
answers
4k
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Why do I constantly have to re-index gears?
I've got a road bike with a high end 11 speed groupset that is about 3 years / 30,000 km old. Chain and cassette have both been replaced recently (i.e. 500 km ago).
What I'm experiencing is a constant ...
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12
votes
4
answers
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What is the average lifespan of rear derailleurs?
What is the typical life cycle of mid-range rear derailleurs, assuming no accidents?
More precisely, what's the average mileage after which it's better to replace it rather than doing tuning all the ...
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12
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2
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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
12
votes
1
answer
9k
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Chart for bicycle component quality?
I'm not very familiar with all the different component groups available and wondered if there's a chart that ranks their quality (or price).
So I'd know that Shimano 105 is the same level as SRAM ...
- 1,116