Fitting a 11/28 from 12/25

[Andywinds]

Hi again, I am running a rear SRAM Rival short cage with a 12/25 cassette. Should I be able to fit a 11/28 without any other mods, Would the chain be ok or would a longer chain be required?. I did check and it looks like the mech should take it.

 

[Sittingduck]

99% sure I have run a 11-28 with a Rival Short cage mech. Chain length will only be an issue if you run it in big ring/28 won't it?

 

[Citius]

Most short cage mechs will take a 28..

 

[raleighnut]

As long as the chain will reach around the big-big sprockets you'll be fine but I'd fit a new one and keep the old un as a (part-worn) spare.

If you ever get to the point where a new chain 'skips' when fitted (due to sprocket wear) then very often a part-worn chain will run OK.

 

[Andywinds]

This bike has not been ridden before. But I get what your saying. I'll dig up another youtube video on changing chains, did it once on the mountain bike, must be the same logic!

As long as the chain will reach around the big-big sprockets you'll be fine but I'd fit a new one and keep the old un as a (part-worn) spare.

If you ever get to the point where a new chain 'skips' when fitted (due to sprocket wear) then very often a part-worn chain will run OK.

 

[raleighnut]

This bike has not been ridden before. But I get what your saying. I'll dig up another youtube video on changing chains, did it once on the mountain bike, must be the same logic!

If the bike has never been ridden then I wouldn't bother fitting a new chain as long as it will cope with the big-big combination on the stand/leant against the wall, you don't want to find out it's too short when riding it.

 

[youngoldbloke]

I always use the machinehead calculator http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc.html

 

[Andywinds]

Thanks for the link, it shows that I will require an extra inch

I always use the machinehead calculator http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc.html

 

[themosquitoking]

Thanks for the link, it shows that I will require an extra inch

Don't we all.

 

[Andywinds]

I've now ordered a new 28/11 cassette and chain. Is the rule of thumb when fitting a larger cassette that for every extra tooth you will require an extra link? So I am going from 25 to 28 so that is 3?

 

[Sittingduck]

Measure the chain before cutting excess links. Different methods to get the chain length correct but I use the following: Select big chainring / smallest sprocket combo. Chain length should be as such that the 2 jockey wheels are directly lined up, one over the other.

Check it is long enough to accommodate the 'no-no' big chainring/largest sprocket combo, although you shouldn't really be using this, as I am sure you know..

 

[youngoldbloke]

I've now ordered a new 28/11 cassette and chain. Is the rule of thumb when fitting a larger cassette that for every extra tooth you will require an extra link? So I am going from 25 to 28 so that is 3?

It may be but I suspect not - see post #7.