Howdy folks, trying to keep my girlfriends rusty old road bike alive. The bottom braked has some play, leading to a cracking sound. I've been able to simply tighten it before, but now the play came back so I took it to a mechanic…
He said the bracket would ideally be replaced, but he had no idea where to find one as these are "super antique"…
So here are my questions: what's this type of bracket called exactly, so I can try to hunt one down ?
Or:
Does anyone know where to get one ? Is there some company that still makes these for all the hipsters and vintage cyclists out there ?
Thank you !
by xgammaray_
6 Comments
It’s a cottered crank.
[https://sheldonbrown.com/cotters.html](https://sheldonbrown.com/cotters.html)
Is it the bottom bracket or the arm that’s loose? Replacing those pins is no fun because there are 6 different sizes, you are better off replacing the bottom bracket spindle with a more modern square taper and going with a much lighter and easier to service alloy cotterless crankset.
You could overhaul the bottom bracket by removing the cotter pin on the non drive side, removing the crank, inspecting the spindle, and packing the cups with fresh grease and bearings. That would usually require replacement of the cotter pin, those can be hard to source in 2024.
If the threading is standard BSA, you could replace the bottom bracket and crank with a more modern square taper three piece crank
Replacing the bearings would be a start, and there were companies making sealed cartridge units that would swap on if they were the same measurements
I’m betting the mechanic didn’t remove it to make his assessment. He just didn’t want the work. Removal of the BB, repacking with new grease and bearings could be all that’s needed. It won’t be butter smooth, but it very likely will be ridable for another decade or two.
Measure the cylinder diameter of the cotter pins if they’re mangled so you can order the correct new ones (9.5, 9 or 8.5mm).
Honestly, that’s a bastard to deal with. As others have said, it’s a cottered crank. Those cotter pins come in multiple, not easily sourced sizes and there is no re-using them. If you do find replacement cotter pins and decide to open it, you may get lucky and be able to clean the races, replace the Bearings and repack it. If you’re unlucky and the races/cups are heavily pitted, you’re looking at sourcing a spindle (which come in different lengths, both for crank attachment and bearing seat) and or cups which would be easier but there are multiple thread pitch varieties for bikes of that Era. I don’t mean to dissuade you but this is a can of worms. Researching the brand and measuring the bb shell will help you narrow down the bb thread pitch and size you need. If I were you, I would ditch those cranks and install an appropriatly sized square taper cartridge and cheap square taper cranks. Or you could roll the dice, find the appropriate pins and try your luck repacking it first. Best of luck