Singlespeed & Fixed Gear - Campagnolo Pista 151 crankset; chainline 45 mm?

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Batavus
03-15-09, 08:42 AM
Uhm that about sums it up. I have this crankset coupled with the original cup and cone pista BB, but the chainline with a 3 mm thick 3/32" chainring comes in at 45 mm exactly. WTF? did Campagnolo change to the standard 42 mm after abandoning 151 BCD?

Using a Phil wood double fixed with Surly cog and a Sturmey Archer 1.6 mm spacer and I still need to go 1 mm outboard with the cog, but my lockring is only barely holding on with 2 or 3 threads engaged, so I'm not putting an extra spacer in there. Nothing serious, it just sucks not to have that chainline perect.

Does anyone else have experience with the 151 BCD crankset?

JohnDThompson
03-15-09, 09:00 AM
No. Here's the chainline diagram from catalog 15 (1967), well within the 151mm BCD timeline:

http://os2.dhs.org/~john/151pista.jpg

Are you certain you have the proper bottom bracket:

http://os2.dhs.org/~john/pista-bb.jpg
Batavus
03-15-09, 11:19 AM
Thanks a lot! My spindles says 68 p120 I think, but I'm not sure. Will take it out and measure. Thanks again!

operator
03-15-09, 12:08 PM
Will take it out and measure.

The diagram indicates a 120mm bb for 42.5mm chainline. Also make sure you got the iso bb.
Batavus
03-17-09, 01:45 PM
My spindle measures 109 mm as per the diagram. It reads: 68 P 120 Z Very odd.I think the number 120 refers to the rear OLD, not spindle length. I have a normal 68 mm BB shell. Using 10, 1/4 inch loose balls per side. It ticks all the boxes, very strange.....
JohnDThompson
03-17-09, 02:23 PM
My spindle measures 109 mm as per the diagram. It reads: 68 P 120 Z Very odd.I think the number 120 refers to the rear OLD, not spindle length. I have a normal 68 mm BB shell. Using 10, 1/4 inch loose balls per side. It ticks all the boxes, very strange.....
Perhaps this (http://os2.dhs.org/~john/campy-BB-specs.pdf)might help?
Batavus
03-18-09, 02:50 PM
Thank you John, for all the tech info!

I have checked everything; my frame is straight, everything is installed correctly. I am stumped. the only thing I can think of is that the BB cups are thin-walled whereas thick-walled cups would put the spindle a couple of mm inboard and I would have extra thread showing on the left, adjustable cup, or am I talking nonsense here?