I'm downgrading the transmission on my 'best' bike to my winter/ cyclo-cross bike but the seat tube on the 'cross bike is smaller. The mech is an Ultegra Triple so if anyone has one of the relevant adapter 'shims' available please let me know.
SJS have them, although they're not cheap (both in price and postage), the shims actually come with some (older?) shimano mechs so someone might have one (or maybe not)
For Sale DK General Lee frame Beccles Suffolk
