Pete Biggs <pLime{remove_fruit}@biggs.tc> wrote in message
news:[email protected]...
> Bert Smith wrote:
> > Does anyone know if you can put a 9spd Shimano Derore/XT/XTR casssette onto a 9spd Ultrega road
> > hub, and still have the STI shifters work?
>
> Yes, Shimano 9sp road and MTB equipment share the same splines, index and cable pull. Might
> possibly be a problem with mech or chain length depending on the cassette ratios...........
>
> > If it is possible, do you need a road or MTB rear mech?
>
> A road long-cage or "triple" mech might cope (in some cases, even a short-cage ouble one can). I
> would try it with existing mech first, then replace if necessary.
>
> Tip: If get problems in bottom gear(s) because of any larger sprockets, after ensuring b-screw is
> adjusted and chain is as short as reasonably possible, consider using a smaller outer chainring to
> enable an even shorter chain to be used. (Shorter chain pulls mech away from the sprockets).
>
I found, using STI, an Ultegra triple rear mech and 11-32 cassette, that the top jockey was just
slightly rubbing when on 32T. It worked, but the jockey probably wouldn't have lasted all that long.
This was using a chain as short as would go over the big/big combination. I didn't fiddle much with
the b-screw, but just got an XT mech, which was fine with no other changes. Based on this, I would
guess that 30T will be OK, 34T will definitely need an MTB rear mech. With 32T, you may fiddle more
successfully than I did.
I don't believe that changing the chainrings will do any good. If the chain is as short as will go
over the ring/sprocket, then the mech is pulled as far forwards (and away from the sprockets) as it
will go. Having a smaller chainring will just mean it is stretched out in a slightly more upwards
direction, closer to the sprockets.
Andrew