rear mech set up .

[cchris2lou]

a bit of tricky one :

On the Colnago MTB I am using Campa Ergopowers , Mavic road short cage derailleur , 8 speed Shimano cassette .

Took it or its first ride this morning , and to my surprise everything is working fine . It wasnt working 100% on the stand but with the pressure on the chain when pedalling it is fine .

But , on the granny ring and on the 2 largest sprockets , the rear mech is touching them . I have tried adjusting the bolt with pushes the mech away but it doesnt make any differences .

it is fine on middle ring .

I am thinking of shortening the chain ???

any ideas ?

 

[terryhfs]

Your cage is too short - fit a smaller ratio cassette to account for the spread caused by using a triple chainring or get a mech with a longer cage.

I had to do this with my Ozark - which has an XT mech but an Ultegra cage fitted. Up front it's 28-38-46 (spread of 1 and at the back it's 12-24 (spread of 12) which gives a total capacity of 30. It's still over the maximum but it works OK with careful chain length.

It could also be that the mech doesn't like the slope of your cassette but that's less likely.

 

[cchris2lou]

thanks .

I might try to find a different mech , but not easy .

 

[hamster]

If you are using 10 speed ergos, they pull exactly the same amount of cable per click as Shimano 8. So you should get it working fine with a Shimano rear mech.

 

[cchris2lou]

I am using 8 speed ergos . the shifting works fine .

it is just the space between the rear mech and the largest sprocket is not enough when on the granny ring . there is enough space for the chain to move but just about .