Originally Posted by
bluenote157
Hmm.. i'm not sure if this answers your question, but I think the double cranks need 109.5 and triples need 118?? I'm doing the same pairing on my cannondale. I have a 109.5 DA and a double 105 octalink. What are the rest of yoru drivetrain components? Is the rear a short cage? If you aren't making this thing into a fixed gear, I think a 2 mm difference in chainline is not going to make a whole lot of difference. you will end up fine tuning the derailleurs??
It's a mixture of everything... Shift/brake is Shimano D/A 7700 STI 9sp at the front, Shimano 7800 10sp front derailleur (works fine on 9sp), 9sp 11-23 cassette on a 130mm rear wheel, the 105 Octalink double crankset, and either a Mavic SSC 7sp rear mech (short cage) or a Shimano XTR 9sp (long cage) depending on whether I can get the range out of the Mavic to cover all rear cogs. I would prefer the Mavic just to keep it a bit more French parts equipped.
I also thought 118 was for triple and 109.5 for double, same as you. My main worry is whether a 109.5 Octalink crank will sit on the same distance from the BB tube edge as a 109.5 square taper crank. I pressume it would, but then I am not sure. Have you installed yours yet? Does it work fine? No rubbing on rear stay?