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Bought used bike, Shimano derailleur does not work – how to repair or replace?

6 min read

Asked by: Jennifer Booker

Can you repair a derailleur?

Some problems can be repaired trailside while others require parts and tools most riders don’t commonly carry. Your bike’s drivetrain is really a simple system, and if you know what to look for, you can easily repair your derailleur yourself.
Apr 30, 2010

How much does it cost to fix a derailleur?

There can be a range of prices for replacement derailleurs, starting around $20 and going all the way up to $700.

How do you restore a derailleur?

Quote from video: The lower cage of the rear derailleur. So that it is in its normal place. And if you remember there was that stuffer screw just on the back. So that needs to clear the derailleur cage.

How do you service a Shimano derailleur?

Quote from video: Now first things first is to make sure the clutch is turned. Off we're going to remove the clutch cover on the radio. First. So that's a two millimeter there's three bolts holding it in place.

Are rear derailleurs hard to replace?

Believe it or not, it’s not difficult to replace the rear derailleur yourself. Before replacing a “bent derailleur” make sure it’s not just the derailleur hanger! First, remove the idler pulley — that’s the bottom pulley of the derailleur.

Can you replace a rear derailleur?

Quote from video: If it's worn out. So to replace the derailleur it's pretty simple so first one take your chain. Off. So it's easy to get to the derailleur and the railer comes off really easily.

How long do rear derailleurs last?

Good quality rear derailleur can last between 3 to 5 years, when unbranded or low-quality ones can last for 2 years, no matter what the durability of the rear derailleur the jockey wheel will wear after time and it can be replaced very cheaply with new ones, on the other hand, front derailleur can last almost

How do you change a Shimano rear derailleur?

Quote from video: Put the mech to the smallest sprocket using your sti's. Pull the cable crimp off the end of the inner cable using some pliers then undo the cable crimper bolt by unscrewing it anti-clockwise.

How do I know if my rear derailleur is worn out?

All derailleurs wear out at some point. Check for wear by pulling laterally on the lower cage. Compare this movement in the linkage of a new derailleur. Sloppy pivot and linkages will produce inconsistent shifting, and the only solution is a new derailleur.
Jul 29, 2017

Can I put any derailleur on my bike?

No, bike derailleurs are not universal. A derailleur that works with one bike may not work with another bike based on factors such as the cage length. Check the difference between the smallest and largest cogs and also the chainring size to determine the derailleur compatibility.
Aug 31, 2021

How do I fix the back gear on my bike?

Quote from video: The only reason you would need to adjust them is if you've changed wheel cassette different derailleur there are a few of the reasons. Anyway what the limit screw. Does is adjust the upper limit.

How do you fix gears on a bike that won’t shift?

Quote from video: You might need to actually detach. The cable from the derailleur all together to allow the case to move over and then reattach and readjust the cable at that.

Can you replace a derailleur without breaking chain?

If the derailleur is riveted closed, you won’t be able to take it off the bike without breaking the chain or destroying the derailleur. If you’re going to replace it, then you’ll need to break the chain anyway to put the new derailleur on. So if that’s the case, then just buy a chain tool and new derailleur.
Aug 18, 2015

How do you fix a rear derailleur?

Quote from video: Pull the chain out and you're ready to remove the old derailleur. Most railers are fastened on with a hex bolt. So you'll need your allen keys for this most of the time you can reuse your shift cable.

How do I know what derailleur I need?

If you are replacing an existing derailleur on a bike, simply count the number of cogs on your cassette and you’re good to go. If your drivetrain’s speed is an unknown quantity, you can count the number of steps that your shifter runs through and add ‘one’ to determine the number of gears your drivetrain has.
Jun 29, 2020

How do I know if my rear derailleur is worn out?

All derailleurs wear out at some point. Check for wear by pulling laterally on the lower cage. Compare this movement in the linkage of a new derailleur. Sloppy pivot and linkages will produce inconsistent shifting, and the only solution is a new derailleur.
Jul 29, 2017

How do I fix my bike derailer?

Quote from video: Pull the chain out and you're ready to remove the old derailleur. Most railers are fastened on with a hex bolt. So you'll need your allen keys for this most of the time you can reuse your shift cable.

Can you replace a derailleur without breaking chain?

If the derailleur is riveted closed, you won’t be able to take it off the bike without breaking the chain or destroying the derailleur. If you’re going to replace it, then you’ll need to break the chain anyway to put the new derailleur on. So if that’s the case, then just buy a chain tool and new derailleur.
Aug 18, 2015

How do you fix a broken derailleur hanger?

Quote from video: So either a chain breaker or in my case I've got the quick link on my chain. So for me I'll just be using the quick link removal pliers just the basic set of allen.

What causes a rear derailleur hanger to break?

Some common reasons for it breaking are: Hitting an obstacle (e.g. tree branch) Going into the spokes (badly set low limit screw or the derailleur was wobbling enough for some reason to get caught in the spokes) Chain too short.
Oct 26, 2014

Can I change my derailleur hanger?

There is no problem to let the derailleur hang from the shift cable while you work. Loosen and remove derailleur hangers fitting screw(-s) that holds it to the frame. Some hangers have from 1 to 3 or more screws to unscrew to remove the hanger.