what type of BB is this?
 

Hello all!

I have a kona crankset I would like to put on my redline mono cog. My LBS said the crankset was some proprietary bmx set that requires an obsolete bb. Here is a picture of the exact crankset, obviously this picture is not mine as it includes the BB The crank arms have slits for a 10 spline bb. I want to say it is isis but the crank arm grooves are square.

http://img331.imageshack.us/img331/1497/img08005aw.jpg

Thanks in advance!

Looks like a Euro to me.

Ten splines? Might be Redline compatible spindle. Might be proprietary to that particular model of crank, too. Shouldn't be a big deal. if you don't need to replace the spindle or arms.

I agree that it looks like a European bottom bracket. BMX doesn't generally sell the spindles with the bottom brackets, so you need to find out what the spindle diameter is. Should be either 19, 20, or 22 millimeter. 20mm isn't very common, that I've seen.

It's kinda hard to tell in the pic if those cups are threaded. If they are, then normally that would be "euro" but they also look like a larger diameter than a typical euro bb shell. Maybe they are supposed to thread in to an American-sized bottom bracket shell? If so, then I agree. That would be an obselete bottom bracket design. If you could press them into an American bb shell despite the 'threading', then the cranks and bb should work.....

Those are way too small to fit an American BB shell. Looking again at that picture, those look a lot like Redline Monster cranks; Single pinch bolt, and what appears to be a shouldered spindle. If that spindle is the same design as the Monsters, it takes a bottom bracket sized for a 20mm spindle. Might not be easy to find.

If you Have a OPC BB shell Frame, you need to buy an adapter. then thread those cups into the adapter.