Originally Posted by
calstar
How do the spacers used with a 68mm bb effect chainline, if at all? I have a XT hollowtech 2 mtb triple I want to install on a 68mm bb road bike, the plastic sleeve on the mtb hollowtech bb is longer than the road which from what I've found on the net should work using spacers. I have the cranks but not a Hollowtech 2 bb so before I buy one I'm looking for info. I didn't find anything specifically regarding chainline, seems like it will move it out 2mm +-. thanks
The Hollowtech crank is made to be wide enough for a 73mm bottom bracket. To make it work on a 68mm bottom bracket, you use spacers to get the width right. You will probably move the spacers around to get the chain line right with more spacers on the left side than the right. I have a bunch of thinner spacers (1mm and 0.5mm) to fine tune the chain line.
You will need to move the crank inboard on the driveside for a road front derailer to work properly. Moving it inboard as far as possible will result in better shifting. The only thing limiting how far inboard you can move the crank is if it hits the frame.