# 105 Hollowtech II spacers?



## mgrysch (May 31, 2008)

I am building up an old Trex 730 steel frame into a commuter/cross bike. I have a Shimano 105 compact crankset (50/34) with Hollowtech II external bearings with a 68mm BB. Both cups seat nicely and the crank slides through easily so the facing appears to be good. When the right crank/chainwheel assembly is seated, the large chainwheel rubs on the chain stay. Park Tools help site and other sources say that the Shimano double road cranksets don't use a spacer but that many others need a 2.5 mm left side spacer and 5 mm right side spacing. They specifically mention DuraAce as not using a spacer but I can not find specifics on the 105. The crankset and bearing sets did not come with spacers. Does anyone know if I should be installing spacers? It does appear that the chainline would be OK with a 5 mm spacer. How much engagement is required on the left side for proper mounting of the left crank arm?
Thanks
Mike R.


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