Singlespeed & Fixed Gear - vintage bottom bracket quizzz

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : vintage bottom bracket quizzz


norskagent
01-07-10, 01:00 PM
According to this: http://www.campyonly.com/history/1974/chainlines.pdf
There is a 1mm difference between a 68-SS-120 BB chainline, and a 68-P-120 BB chainline.
I have the 68-SS-120 bottom bracket. So the question now is, where would a campy pista chainring line up on the spindle, closer to the inner or outer chainring, or "centered" at 43.5mm?


JohnDThompson
01-07-10, 01:46 PM
The 68-SS-120 is a road spindle, intended for use with double chainrings. If you're using a road crank, running the chainring on the inner plateau should give you a good chainline. If you're using a track crank, you'll want the 68-P-120 spindle (unless you have an old frame with 110mm rear dropout spacing, in which case you'll want the 68-P-110).

norskagent
01-07-10, 01:58 PM
I want to use a track crank on a road spindle. The link above indicated that the 2 chainlines are only ~1mm different, assuming my track chainring is at the 43.5 road chainline. I don't want to spend big $ for a track bottom bracket just to perfect my chainline by a millimeter.


JohnDThompson
01-07-10, 07:21 PM
I want to use a track crank on a road spindle. The link above indicated that the 2 chainlines are only ~1mm different, assuming my track chainring is at the 43.5 road chainline. I don't want to spend big $ for a track bottom bracket just to perfect my chainline by a millimeter.
If you already have the parts you're proposing to use, you have nothing to lose by trying it.

norskagent
01-07-10, 07:40 PM
I did - I think it's pretty close. I measured a hair over 43mm at the chainring, and right at 43mm at the rear cog. I put a 0.5mm spacer between the cog and hub. I haven't ridden it yet but hopefully it will run smooth and silent. Also, there was only ~2mm clearance between the chainring and chainstay. Here's a pic, taken just a few minutes after I finished.
http://img.photobucket.com/albums/v218/jvpro/007-1.jpg

BoozyMcliverRot
01-07-10, 10:07 PM
Very nice ride.But i wouldnt worry at all about a 1 or 2mm diff.