Changing rear cassette

[andrew boaz]

Hi

Apologies as i am a cycling newbie in terms of replacing equipment on my bike.

Can i replace the 11-28 rear cassette on my bike for a 12-30 rear cassette without having to replace my rear derailleur set up?

My chain and rear cassette are showing wear which seems an opportune time to replace my cassette and get the gearing more suited to my own riding rather than how it came out of the shop, my rear cassette is currently 105 and i would like to upgrade this to ultegra and also stick an ultegra chain on while i am at it as my chain ring and derailluers are ultegra . Although i wanted to ask if any mileage in me putting a dura ace chain on rather than ultegra as they only seem to be a couple of quid dearer on evans cycles at the moment.

Thanks for putting up with my newbie question and any response is gratefully received.

Andy

 

[boydj]

12-30 should be fine. You may need to check that the jockey wheel is clear of the cassette and adjust the 'B' screw slightly if there is a problem.

 

[andrew_s]

Can i replace the 11-28 rear cassette on my bike for a 12-30 rear cassette without having to replace my rear derailleur set up?

Probably, but not certainly.

It depends on how long the gear hanger on your bike is. If it's not long enough the top jockey wheel will be too close to the large sprocket, and it will either not change onto it, or run roughly as each link forces its way through the too small gap. You can often persuade a marginal case to work by fiddling with the B-screw on the mech (just below main pivot), or the chain length.

 

[HLaB]

I'd say probably not if your existing cage is a short one but I'm no mechanical expert.

 

[andrew_s]

The cage length doesn't affect whether you can use a cassette, just whether the chain goes slack when in small/small (which you shouldn't use).

 

[Andy_R]

Have a look here. Nice simple description of cage length etc.