freewheel cog

[stephen.rooke]

how much extra clearance between cog and derailure does a 28 tooth cog need to have over a 24 tooth one. ive broke a tooth so need a new cog but theres not a lot of room and have seen a 12-28 for £10 and think it would suit me better than the current 14-24

 

[stephen.rooke]

i need to learn to read, the £10 one was a casette lol, still need to know about the clearance though

 

[HovR]

What type of bike is this on, and what rear derailleur is it?

A lot of road rear derailleurs tend to have a max tooth size of 27, whilst a common max tooth size for mountain bike/hybrid rear derailleur is 32ish I believe.

 

[stephen.rooke]

its a road bike, ill check what dérailleur it is

 

[stephen.rooke]

just looked and it says index sunrun on the side.

never heard of them lol, must be a cheap chinese make

 

[TheDoctor]

It'll be a clone of a low-end Shimano one - like a Tourney.
I'd go for it with the 14-28.
Most mechs will work on a 28T, and it won't cost a fortune to replace that mech anyhow, if you need to.

 

[simon.r]

You should be able to move the derailleur away from the cog by adjusting the B-screw (assuming it has one).

Take at look at this guide (about half way down the page): http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur