Changing a cassette

[iain.bowran]

I have a 10 speed focus cayo with a Tiagra 52/36 chainset. The rear mech is a Tiagra R4700 and the cassette is 12-28. Does anyone know if I can swap this cassette for 12-32 so I can get up the local hills with a bit more ease. Will I have to replace the chain for the larger sprocket?

[Brucey]

according to shimano

RD-4700-SS will accept up to 28T rear sprocket and
RD-4700-GS will accept up to 34T rear sprocket provided you have a double chainset (32T if triple)


with a 32T sprocket you will need another 1" of chain; if you have at least this amount in excess of what you need to run big-big at present, you probably won't need a new chain.

However running a worn chain on a new cassette is not a good idea, so I'd buy a new chain and keep it with the new cassette anyway.

cheers

[iain.bowran]

Thanks Brucey. I’ll check whether it’s SS or GS.

[willem jongman]

And next time you need to change the front chainwheels, get something smaller as well. You cannot go much lower, but even 2t will make a small but relevant difference.

[Marcus Aurelius]

You may want to invest in one of these as well.



It’s this

https://www.sigmasports.com/item/Wolf-T ... anger/DOQG

It will allow you to go with a much bigger sprocket than you could with a given derailleur cage length. Quite a useful bit of kit to have, which saves a lot of potential aggro.

[andrew_s]

Thanks Brucey. I’ll check whether it’s SS or GS.

Give it a go with the 32 cassette and new chain before you spend further money, even if it is an SS mech.
It's common that you can run a larger cassette than the specs say.

If it doesn't work properly, you can put the old cassette and chain back on whilst a replacement rear mech arrives

[robgul]

You may want to invest in one of these as well.



It’s this

https://www.sigmasports.com/item/Wolf-T ... anger/DOQG

It will allow you to go with a much bigger sprocket than you could with a given derailleur cage length. Quite a useful bit of kit to have, which saves a lot of potential aggro.

Experience shows these things (and the Wolf one) to be a bit risky with bending the original hanger or damaging the frame - Shimano invalidates any warranty on its mechs attached to one of these .. and if the bike is under warranty I'd think twice about fitting one.


Rob

[Marcus Aurelius]

You may want to invest in one of these as well.



It’s this

https://www.sigmasports.com/item/Wolf-T ... anger/DOQG

It will allow you to go with a much bigger sprocket than you could with a given derailleur cage length. Quite a useful bit of kit to have, which saves a lot of potential aggro.

Experience shows these things (and the Wolf one) to be a bit risky with bending the original hanger or damaging the frame - Shimano invalidates any warranty on its mechs attached to one of these .. and if the bike is under warranty I'd think twice about fitting one.


Rob

I’ve never had any issues.

[willem jongman]

A longer B screw on the rear mech often does the job.

[robgul]

A longer B screw on the rear mech often does the job.

.... and the old MTB trick of screwing the B screw in from the other side gives a bit more length with the screw head against the stop.

Rob

[Marcus Aurelius]

A longer B screw on the rear mech often does the job.

.... and the old MTB trick of screwing the B screw in from the other side gives a bit more length with the screw head against the stop.

Rob

The backward B screw trick is fine, but it’s a bit of a ‘bodge’. A longer screw is preferable.