Which bottom bracket do I need?
Hi, I bought a frame on eBay for which no rental data is known…i.e. no manufacturer etc. (Old frame 26" and definitely before 2015, possibly even 2010)
The measurements I have are as follows:
Thread diameter: 33.5-33.7mm
Width: 69mm
Like FelixLingelbach, I suspect it's more likely to be 34.8 mm in diameter. And a width of 68 mm, because, to be accurate, the paint on the front sides of the bearing housing would have to be milled off.
That would make the whole thing a BSA 68 shell. Accordingly, you need a bottom bracket that can be screwed into a BSA 68 shell.
And of course, one of all BSA 68 bottom brackets whose axle fits the crank you have chosen.
I have never heard that in 20 years of working with bicycle technology.
I know the "bottom bracket" as a variant of the bottom bracket, explicitly with internal (instead of external) bearing shells.
Luckily, you never stop learning. The bottom bracket is not a variant of the bottom bracket, regardless of where the bearing cups are located.
Yes, I expressed myself clumsily. I know that some people categorize it that way.
I don't usually use the term "bottom bracket" at all. It's the bottom bracket, that's it. And the crank is mounted in/on the bottom bracket in some form. It's a separate component.
There isn't. Isn't it 34.8?
https://de.wikipedia.org/wiki/Tretlager#Befestigung_im_Bicycleframe