Bicycles Stack Exchange
Bicycles Stack Exchange

Questions tagged [derailleur-rear]

Questions referring to the derailluer responsible for moving the chain along the cassette

602 questions
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Upper pulley wheel suddenly totally off chain

Went for a bike ride today and thought the chain had slipped. Stopped and found the upper pulley wheel of the rear derailleur assembly was completely out of contact with the chain (please see photo)! Nothing we do seems to bring it back into contact…
Pietakio
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Do oversize pulley wheels increase derailleur capacity?

Do the large custom pulley wheels and cages increase the capacity of a derailleur significantly? There are reasonably priced ones on E-bay with 16t pulley wheels. Every demo of these I've seen says you'll need to install a longer chain when you…
Fred the Magic Wonder Dog
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Devastated- Ribble R872 Ultegra damage to rear dropout

Please see attached photo of damaged frame where rear wheel locks in. The rear derailleur hanger snapped clean off, so it did the job it is supposed to but there is damage to the frame. I’m being quoted up to £1000 to fix this as bike will need to…
John Gibbons
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Rear derailleur too far out

All I did was change the rear tyre and now the rear derailleur can only access the highest 4 sprockets out of 7. I have followed Parktool videos on adjustments (including pulling the cable probably tighter than I should) to no avail. Adjusting the L…
Alan Escreet
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What could have caused a rear derailleur to end up in the back wheel suddenly?

This is a similar question to What exactly happened to my rear derailleur? but with some significant differences. My bike had recently been serviced (about 3 weeks/500 km previously). All that had been done to it since that was a little tightening…
Chris H
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Do all or virtually all rear derailleurs actually have linear actuation ratios?

Adapter devices such as the Jtek Shiftmate and Wolf Tooth Tanpan are designed with the notion that the actuation ratio of the rear derailleurs they're being attached to are dead linear. So, for example, by multiplying a shifter's input pull by an…
Nathan Knutson
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Servicing Shimano Centeron Jockey Wheels

I'm servicing my rear derailleur jockey wheels (pulley wheels) for the first time. They have about 20,000km on them. The derailleur is a Shimano Deore LX, and the first jockey wheel I've taken apart is the Shimano Centeron G-Pulley. I've…
SSilk
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What is going on with my derailleur?

I was on a ride a few months ago and while shifting, my chain came out of my derailleur. So this is a little confusing. Let me explain. The chain was resting on the outside of the bottom part of the rear derailleur cage. There is a little silver…
M Dabbs
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Does the initial position of the B-tension screw matter?

When I'm installing a rear derailleur, should the B-tension screw be in a high or low setting or does it not matter? I've tried searching for information on this but no one seems to mention this so it seems like it doesn't matter. The B-tension…
Izaan
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Why rear derailer has limit on front chainring difference?

Just as an example, Shimano RD-M786-SGS (as most other RDs) specification says "Max. front difference: 22T". Why is rear derailler limited in front max difference? It is clear that it is limited in total tooth capacity, but max front difference is…
Konstantin Shemyak
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Can't find the B-tension screw in rear derailleur

I am trying to register my old rear derailleur (a 15-year-old Shimano "7sis"), and I'm trying to find what every guide calls the "B-tension screw". I looked everywhere and couldn't find anything that looks like it. I only have the two screw for the…
Bob-it
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Shimano RD-TY20 "Direct Attachment" rear derailleur mount style replacement

I have a Shimano RD-TY20 derailleur with a date code of 1989. It is mounted on a frame which is marked as 1984. This frame is made of steel, and the derailleur hanger is part of the frame. I want to modernize the drivetrain (Please reserve your…
jayded-bee
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Does the rear derailleur have a range of motion that exceeds that needed to move between the planes of the smallest and largest sprockets?

The distance between the plane of the largest sprocket and the plane of the smallest sprocket in a Sora cassette is about 34 mm. When the rear derailleur cable is untethered, the spring in the rear derailleur brings it outside of the plane of the…
Sam7919
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Largest sprocket below derailleur specification

I will install a Deore RD-M6000 derailleur on a bike that already has its cassette. The Shimano RD specification claims for a 32 to 36 largest sprocket, but my cassette (almost new) is a 11-28. Is it a problem to use this slightly smaller sprocket?
rvil76
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Is there a reason why the range of acceptable indexing varies across gears?

I was having issues with indexing my Shimano 105 R7000 RD previously. Basically, even after aligning the rear derailleur hanger as accurately as possible and changing cables, I noticed that, the acceptable indexing range seems to shift as I shift…
trenz
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