quick question! road mechs content

Apols for ROAD related question, but one of you guys will be bound to know...

When using a 9 speed cassette with a triple front set-up, what's the max size rear cog I can realistically use with a short cage rear mech... 27, 28, 29? My smallest cog is likely to be a 12 and the front rings are 30-39-50 (so 20 difference up front).

Is there a rule of thumb? Is it the difference between 9th and 1st that is key? Or the difference between 'big to big' and 'small to small'?

You should find your answer here:

http://www.retrobike.co.uk/forum/viewtopic.php?t=85597

If you never cross-gear (big ring/biggest cog or small/small) you can run most combinations with a short-cage, but the one time you forget could cost you a rear mech.

that's good of ya - thanks mecha!!

One other thing to remember is that road mechs have a different slant on the parallelogram, so they don't get on with very large rear cogs. Campag will manage up to 29, Shimano allegedly 30.

Just be careful if you are hoping ot run something huge like a 32 or 34, e.g. in a 1x9 setup.

cheers ham

probable set up will be 30/39/50 and 12-28