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Chainline question: Hitting the pins in 39 ring and 2nd cog:(7 posts)

Chainline question: Hitting the pins in 39 ring and 2nd cog:Spunout
Feb 4, 2003 4:21 AM
Chorus 10 on a 2001 Lemond Buenos Aires. I was sure that I would be able to use my second cog on the small ring (53/39 X 13/29) for the 39/14 gear.

The pickup pins on the big wheel are tinging on the chain on the 14, not at all on the 15. It is useable, but I'm worried that if I hit a bump, one of the pins pick up the chain, and I'll have a mess up front.

If I shim the BB 1mm out, how does this move the spindle outboard? Wouldn't it just loosen the whole assembly? Should I face the left side of the BB to push the whole unit to the right? Or, I may just leave it alone.
Feb 4, 2003 5:00 AM
I notice a very slight rub in the 39/2nd cog combo. Doesn't hurt a thing, but I don't ride for extended periods in this combo. Don't worry about the big ring picking up the chain. It won't happen.

Shimming the BB 1mm might help, but not much. Using a shim will not require any changes to the BB shell. The drive side is tightened down first, the left side cup has no contact with the face of the BB shell. It will merely be set in 1mm further than before, when it's torqued down.
normal...Rusty Coggs
Feb 4, 2003 5:35 AM
There are 2mm shims availabe for cheap.
And 2mm is what you need. That's whatOldEdScott
Feb 4, 2003 5:38 AM
my Lemond needed. 1mm won't do it. Trek is aware of the problem, even have specific neato-looking shims they recommend you use.
Okay! Will e-mail support, my LBS is a dealer. Thanks!! nmSpunout
Feb 4, 2003 5:53 AM
re: Chainline question: Hitting the pins in 39 ring and 2nd cog:Eric_H
Feb 4, 2003 1:54 PM
I do not know what the exact cogs are on a 13-29 but I'm guessing 13-14-15-17-19-21-23-25-27-29. FYI 39x14 is the same as 53x19, so it would seem more sensible to leave the BB as is and just stay away from 39x14 (or 13).
re: Chainline question: Hitting the pins in 39 ring and 2nd cog:flakey
Feb 7, 2003 5:17 PM
If the chain was assembled with the new HD-L 10 connector, make sure that it the connector pins (similar to Shimano HG pin) were installed from the inside of the bike. Campy says that if you dont, the slight protrusion of the connector pin can hit the pickup pins on the big ring. If it was installed with a permalink then its just a spacing issue.