# Derailiuer hitting cassette



## Olbeast (Mar 23, 2021)

I just installed an 11 spd 11-51t cassette on my bike in place of it's original 2 x 9 setup. Went with shimano deore m5100 groupset. On installation of the shifting cable i noticed that the derailleur arm where the cable is attached is hitting the cassette?! I must be missing something cause i really don't think this is how it's engineered. The hanger is not bent and makes no difference with b screw all the way in or out, still touches. Help!!!


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## robbbery (Jan 12, 2021)

The cassette and derailleur are both 11 speed deore? Also, what did you do to verify that your hanger is straight?


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## Cleared2land (Aug 31, 2012)

Barrel Adjuster?


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## robbbery (Jan 12, 2021)

Also, I wonder if it could be the result of a mismatch between "direct mount" and "standard" parts.



https://wheelsmfg.com/blog/standard-mount-vs-direct-mount-derailleur-hangers.html



E.g., if you somehow wound up with a derailleur that is shaped for one of those extra long derailleur hangers, but you need the kind with the b-link instead, that would cause the derailleur to be positioned too close to the cassette.


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## Aresab (Mar 27, 2007)

As a thought without a real good pic. Take a look at the derailleur attachment screw there is what looks like a thick black washer that has a b-screw stop in it. Double check that the b-screw and the stop are behind the hanger stop. Another words the b-screw should rest on that piece (the stop) and not the hanger.


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## kevine1785 (Mar 29, 2021)

A few things... when you are working with a newer clutch derailleur you have to push on it a LOT more to straighten out without a chain on it so try prying it straight. if thats not it your rear derailleur may be a medium cage not a long cage. I would double check to make sure you didnt get sent the 2x11 5100 derailleur (42t max cog). If you did return it. OR if you cant just get an extender like this: Wolf Tooth


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## alpinerider38 (Jan 1, 2021)

I'd look at what Aresab suggested! Had this exact same thing happen the other day and it was the stop for the b tension screw had turned about 45degrees,took me a moment to figure out what had happened!


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## 127.0.0.1 (Nov 19, 2013)

b screw used to just be 'an adjustment' you could take or leave back in the day
now it is critical to getting pizza sized cogs shifting correctly

likely problem as stated above...
-direct mount vs standard
-b screw
-wrong range der


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## Olbeast (Mar 23, 2021)

robbbery said:


> The cassette and derailleur are both 11 speed deore? Also, what did you do to verify that your hanger is straight?


Yep both 11 spd. How do you check if straight? Looked pretty straight


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## Olbeast (Mar 23, 2021)

Aresab said:


> As a thought without a real good pic. Take a look at the derailleur attachment screw there is what looks like a thick black washer that has a b-screw stop in it. Double check that the b-screw and the stop are behind the hanger stop. Another words the b-screw should rest on that piece (the stop) and not the hanger.


Yeah fair call, I'll double check this arvo


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## sgltrak (Feb 19, 2005)

Olbeast said:


> How do you check if straight? Looked pretty straight


You won't be able to tell if it is straight without putting a derailleur hanger alignment gauge on it.


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## Monty219 (Oct 26, 2020)

I once (thought that I) had the same problem. My setup looked the same as yours until I put a chain on and the chain tension pulled the derailleur down/ forward and out of the way of the cassette. No problems with that one ever since. Have you tried installing a chain yet?


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## Olbeast (Mar 23, 2021)

Monty219 said:


> I once (thought that I) had the same problem. My setup looked the same as yours until I put a chain on and the chain tension pulled the derailleur down/ forward and out of the way of the cassette. No problems with that one ever since. Have you tried installing a chain yet?


Yeah I've read that on a few threads. I'll try that this arvo aswell. Problem is if i break the chain where needed and install it. Then i find out i actually need a goat link my chain will be too short, therefore i need another chain right. Headspins!


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## Monty219 (Oct 26, 2020)

Olbeast said:


> Yeah I've read that on a few threads. I'll try that this arvo aswell. Problem is if i break the chain where needed and install it. Then i find out i actually need a goat link my chain will be too short, therefore i need another chain right. Headspins!


Yes, tricky indeed! 1. Could you just pull the derailleur by hand with no chain installed first, to see if you can create the clearance sort of theoretically? If so, then next step: install chain through the drivetrain with derailleur already in largest cog, leave open ends at bottom, temporarily hook chain together with an improvised spoke tool (see picture below for 2 examples, top one works better) you obviously wont be able to pedal it, but should be able to check clearance and play with chain length before committing to cutting it.


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## bow53 (Jan 8, 2021)

I know I had an issue of the derailur hitting the cassette. Took it to the shop and they were like " ya your derailur is bent" I managed to bend it back and then a few months later the clutch went out so I ended up getting a new derailur


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## prj71 (Dec 29, 2014)

I'm thinking you purchased short cage instead of long cage


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## Olbeast (Mar 23, 2021)

prj71 said:


> I'm thinking you purchased short cage instead of long cage


Nah definitely long cage


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## robbbery (Jan 12, 2021)

Don't forget to update the thread once you figure it out!


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## Olbeast (Mar 23, 2021)

robbbery said:


> Don't forget to update the thread once you figure it out!


Yeah i definitely will. Just been smashed with work and haven't had time to work on it yet


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## fishwrinkle (Jul 11, 2012)

sgltrak said:


> You won't be able to tell if it is straight without putting a derailleur hanger alignment gauge on it.


...or remove and lay it on any machined surface. fvck i used a tri square on edge while on the bike to determine. my point is that it doesn't need specialty tools


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## pillsandthrills (Sep 4, 2014)

I'm having similar problem with the same group set as OP. I definitely have the stop in the right place behind the hanger stop. Even if I have the B-screw totally screwed in, the top jockey of the derailleur is still pushed hard against the smallest gear. The derailleur model is RD-M5100-SGS, which looks like it might be a long cage based on searches, so I guess this could be the issue?

I've debated just putting the chain on to pull out the derailleur. What's next? Try goat link? Would that give me enough extra extension if this is a long cage issue?


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