cassette advice

[srj10]

thinking of changing my cassette from 12-25 to 12-27 do i need to change the chain as well

 

[User6179]

I would unless the chain is newish .
Chain length might be a problem also with the bigger 27 tooth cog .

 

[srj10]

I would unless the chain is newish .
Chain length might be a problem also with the bigger 27 tooth cog .

chain is fine just not sure about the length,thanks

 

[User6179]

chain is fine just not sure about the length,thanks

Stick it on big ring and biggest cog and see if you have any slack .

 

[T.M.H.N.E.T]

I've went up more teeth and didn't even consider changing chain

 

[adscrim]

I frequently change between a 25 and a 27 becasue of using a old wheel on the turbo and don't have any problems.

 

[Nigelnaturist]

Its fine if you have a chain for the 27th as its just like going from 27 to 25 by having the 25 is the first position,
It may pull the RD too far forward if it is too short i.e. going from a chain for max rear of 25 to 27, what @Eddy said, chain around both large rings without going through the RD and you should have one whole link extra overlap, in fairness though it is likely to work, there may be a little more chain noise as the RD is further forward

 

[youngoldbloke]

For this sort of job the machinehead software calculator.is really helpful