Bicycle Mechanics - Hollowtech II spacer placement?

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Yan
06-12-09, 12:02 AM
I am converting my Surly Cross Check fixed gear into a touring bike. I have a Shimano 105 triple (FC-5603) crankset which currently has one spacer under the right adapter and none under the left. This gives me a straight chainline for the fixed setup (but with cranks offset from centreline).

The bike is getting 3x9 gears, with a standard 9 speed mountain cassette on a 135mm hub in the rear. The bottom bracket shell width is 68mm. What is the correct bottom bracket spacer configuration in this situation? I've looked through the Shimano documents but they are unhelpful.

Torchy McFlux
06-12-09, 02:03 AM
Shimano triple road cranks should always have a distance of 45mm between the center of the seatttube and the middle of the middle chainring.
By Shimano's tech docs (http://techdocs.shimano.com/media/techdocs/content/cycle/SI/105/FC-5600-5603/SI_1GE0C_001_En_v1_m56577569830646763.pdf) it looks like you should have that spacer on the left side.
Panthers007
06-12-09, 08:39 AM
Same for the Shimano Ultegra Hollowtech II. The spacer (only comes with one) goes on the left-side after the external-bearing is torqued on.

Yan
06-12-09, 04:33 PM
If there is no spacer on the drive side, what keeps the chainline constant when the same parts are moved to a 73mm bottom bracket?
laura*
06-12-09, 05:28 PM
If there is no spacer on the drive side, what keeps the chainline constant when the same parts are moved to a 73mm bottom bracket?

These parts won't work with a 73mm BB shell.
Panthers007
06-12-09, 05:47 PM
That's not quite correct. You'd need a Hollowtech II for Italian spacing:

http://harriscyclery.net/itemdetails.cfm?ID=2483