Bicycle Mechanics - Platinum Pro Track BB adjusting for chainline
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.
02-22-06, 11:29 PM
I've got a 130mm dropout spacing frame with a 120mm track hub that i've added two 5 mm spacers to either side. I have an FSA platinum pro track bottom bracket that i specifically had installed because FSA said they were adjustable for chainline. My LBS looked up the BB and said that it wasn't adjustable due to the fact it had a lip on the side to stop the threading (I checked and mine doesn't have this so mine must be newer I guess). How do I go about adjusting the BB to give me perfect chain line? I assume my spacing of the axle is appropriate, and I'm hoping I can adjust the rest just using the BB.
Thanks for the help
02-22-06, 11:52 PM
thanks Cbolt, I've been hearing conflicting advice from people:
1. the method you outlined.
2. other people have told me to "shift the bottom bracket unit in the shell".
Should I take it back to my LBS and have then do it your way and mention the shifting way and see if its bunk?
Where can I get the spacers you mentioned?
Sorry, thanks again for the help.
since your bottom bracket doesn't have that lip (which none of the adjustable-chainline ones should), adjusting the chainline is as simple as "shift the bottom bracket unit in the shell"
since there's no lip on the outside to act as a stop you can add all the spacers in the world and they're just going to fall off, there's nothing there for them to well, "space"
install the bottom bracket and drive-crank as you normally would, find out what direction the chainline needs to go in. ie: do the cranks need to come closer inboard or further outboard?
remove the cranks, loosen the drive-side of the bb (if it needs to go outboard) and tighten the non-drive side down against it. vice-versa if it needs to go inboard.
reinstall the cranks and check again.
repeat until your chainline is correct. one side could very well extend a little bit outside the bottom bracket shell. that's okay. the other side will be sunk into the shell. that's okay too.
Powered by vBulletin® Version 4.1.12 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.