- Double specific chainset won't work with my old shifter. What now?
My new xt double chainset wont work with my old triple shifter. Guess shimano have moved the position of the rings on the cranks. So now I need a shifter that pulls the right amount of cable. Which one do I need? Only the sram shifters seem to be double specific. Will all 10 speed shimano shifters work?Posted 6 years agospeaker2animalsSubscriber
In what way do the old shifters not work with the new chainset? Over shift/under shift? Have you reset the end stops on your mech? BTW is there a double and triple specific front mech now? I’d have thought that a mech for a double could have a slightly smaller plate to plate dimension?Posted 6 years ago
Yes should have made it clear that I had a double setup before with a xt triple chainset 22/36 rings and a slx mech with the shorter cage. Shifting was perfect. Got 73mm bb shell so got one spacer on the driveside. Small switch on the shifter is what I needed to know 😀Posted 6 years ago
Are you going from 22/36 to26/38 or 28/40? afaik, the chainline IS different and the front mech probably won’t work then. The SLX double mech is meant for chainrings in the inner/middle position and on the xt doubles the chainline is further out. The cage profile won’t be correct for the rings anyway, although shouldn’t be too far off.
I could quite possibly be wrong here!Posted 6 years agospeaker2animalsSubscriber
According to Shimano XT website the Chainline for the current triple is 50mm whereas for the double crank it is 48.8mm.
I assume that this is a measurement from the centreline of the BB shell to a notional centre of the rings (so on a triple it would be where the middle ring lies, on a double I imagine a line between the two rings)?
Just had a look at Sheldon Brown and my assumptions are correct. However it looks to be a minefield depending on frame type and crank being used.
You say it either rubs on cage or drops off rings. On which side (ie rubbing on Large ring/dropping off little)? I’m not being condescending or don’t mean to be. Have you adjusted the end stop screws? Is the outer mech plate as close as possible to the large ring (1-2mm I think is recommended).Posted 6 years ago
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