New cassette, now I got noise

Doyleyburger

Veteran
Location
NCE West Wales
So iv just changed the cassette on my winter bike from a 11-24t to 11-32t. Basically now I can't seem to shift what seems to be a noise that's coming from the jockey wheel. I have adjusted the B tension screw to try and allow for the bigger cassette but no joy !
I'm not sure whether my derraillier can take a 32t or is my chain now too tight because of the now much bigger cog......perhaps both??
Would appreciate any help
Thanks
 

Globalti

Legendary Member
You may need a long cage derailleur to take up the slack but be aware also that with a long cage derailleur, some manufacturers actually fit a longer hanger on bikes with the bigger gear range, in order to get the jockey wheel the correct distance away from that big cog.

Here are the hangers from a Roubaix Comp that came with 11-27 and a short cage and a Roubaix Sport that came with 11-30 and a long cage:

20140503_060602_zps6fdbf4a9.jpg
 

raleighnut

Legendary Member
Location
On 3 Wheels
To check chain length it should run over the big-big rings with 2 links over (not running through the rear mech) and as for the capacity of the rear mech it all depends on the tooth difference between the front rings and the difference on the cassette ADDED together.
 

lpretro1

Guest
f you didn't change the chain at the same time it may be part of the problem - but it's a big difference going fro 24 to 32 teeth so prob v short too!
 
Location
Loch side.
Moving from a 24 low gear to a 32 is certain to make the chain too short for the job. If you are on that gear with the chain on the big chainring and your jockey is bent forward by more than 45 degrees to the horizontal, your chain is too short. However, just lengthening the chain is not going to solve the problem, you'll have to get a compatible jockey as well. Rear derailers have different capacities and these capacities are measured in teeth difference. In other words, the difference between the shortest and longest wrap of chain on the bike.

For instance (and assuming you have a 39/53 in front), your old teeth difference was (24-11) + (52-39) = 26.
The new difference is now (32-11) + (52-39) = 34

Short cage road bike derailers cannot handle that much difference and you'll have to change the derailler too. If your derailer is already capable of the range, then your chain is too short. What jockey is on there?
 
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