Armed Polite Society
Main Forums => The Roundtable => Topic started by: zahc on October 10, 2020, 10:06:28 PM
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I only remember back when men were men and cranks had square tapered spindles. I bought a bike online and the cranks are binding. I took the left arm off and the binding stopped but I don't see any adjustments. I don't think it's a good idea to loosen the bolt, right? I assume it has to stay good and tight and I need to fix rhe binding some other way. The right bearing cup appears to have 2 fat spacers under it, which might be for the chainline, but I don't see any way to adjust anything.
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If it stopped binding after you removed the crank arm then the crank arm seems like it is the issue.
There really isn't any adjustment to cartridge bearing bottom brackets other than properly snugging them up into the frame.
Have you tried reinstalling the crank arm, torquing it to the proper spec?
Maybe it was massively over torqued?
What is the bike? High, med or low price point?
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https://www.parktool.com/blog/repair-help
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https://www.parktool.com/blog/repair-help
The Park Tool videos are great.
Really well thought out and executed, like being in an actual classroom.
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The problem is there are apparently hundreds of different standards now and I have no way of knowing mine. It's a Boris X5 with "lasco" 2-piece cranks.
I know nothing about bikes but I know bearings, and I can tell the problem is too wide of space between the bearings. The crankarm has to bottom out on the spindle to be right. I need to move the bearings inward to remove the binding but not so much the crank slaps back and forth after tightening. A really stupid design. Even cottered cranks from 1930 had bearing adjustments. With this thing it looks like shims are the only way to adjust it. I don't have a special tool to take out the bearing cups to put in a thinner spacer, so I will probably mill 0.030 off the left crankarm. There's plenty of meat there and if I take off too much I can shim it back or get a wavy washer to take up slack.