I’ve written before about the changing standards in the mountain bike world, but I didn’t spend much time in that post discussing bottom brackets. They’ve gone through changes too, like so many other components.
A lot of those changes have improved strength and performance, but I’m not convinced that the current standard is an improvement. And a recent product development meant to “fix” the issues with that standard is making me think I’m right.
A quick review though;
The bottom bracket shell on all bikes used to have threads on either side. You threaded a cup onto one side, slid the spindle in, then threaded a cup on the other side. Then cartridge bottom brackets came along – they had the spindle and one cup as a unit. You threaded that into the frame, and put a cup in the other side to hold it in place. No finnicky tightening and re-tightening was required in order to get the tension just right.
In other words, no expertise required.
Anyway, the next evolution moved the bearings were outside the shell, allowing them to be bigger, the spindle to be larger in diameter, and the entire operation to be stronger.
Now, I used the word all earlier. It’s the bicycle industry we’re talking about, so it’s never all. Fisher, Merlin, Klein – and a few others – used a press-fit bearing instead of threading. Why, I don’t know. I guess you could make the argument that replacing the bearings was easier, but I don’t know if I agree.
The rest of the industry sure didn’t agree, because all of these companies gave up on this arrangement eventually – by 1995 for sure.
But here we are in 2015, and most of the higher end bikes out there are now using press fit bearings.
I think this is mostly due to carbon fibre. You can’t thread carbon like you can metal, so carbon frames had to have a metal insert bonded in for the BB to be installed. So, just pressing in a bearing was thought to be better, or at very least, easier
But, why would you do things the easy way, when you can do it the hard way? Why not chase the threads and face the BB shell before installing to ensure a perfect connection between BB and shell? I guess because pressing them in is easier.
The problem with easier in this case, is that these press-fit bearings are creaking. Which means you have to repeatedly take them out, clean them up, and put them back. I guess. I’ve never had a bike with that, but this is what I hear.
But it’s cool man, we can fix that. Check this out;
Does anyone else find this comical? Notice the threads that are holding the two pressed in cups together? Couldn’t we just put those threads on the cups instead?
Oh wait, we did that already.