My bottom bracket is a Chin Haur 52, I'd like to replace it with a Shimano. Can I use the UN54, 55, 71, 72, or 91?

Also does anyone still make a cottered crankset? The crankset that came with my Azor is a 1piecer.

So I have some confusion to what crank/BB design you have. A quick Google on "Chin Haur 52" shows only tapered square designs but you say "The crankset that came with my Azor is a 1piecer" which is not tapered square. (in my world 1 piece means the left and right arms are 1 piece with the portion running through the BB shell). One more time a photo would solve this question before it is asked. Andy

I wonder if "one piece" means an Ashtabula crank.

As to cottered cranks, no, no one makes them any more as it was a very heavy, obsolete design. There are a few repair parts still available but no current new ones. There are numerous better types.

I don't have a camera to take a picture, but the BB is a Chin Haur 52. (square taper) the crankset/chainwheel is a press fit to the axle.
I'd like to put a more robust chainwheel/crankset on a more robust BB.
I've read the reviews on the CH52 and they aint not good.

OK, square taper. Any of the series of UNs should work, try to match the spindle length. before you remove the arms take a look at the drivetrain's chainline and the clearance between the chain stay and the chainring. Replacing the BB is one way to positively change the current crank's chainline. Assuming all is good location and that the OEM spindle is symmetrically positioned in the BB unit just get the same size. Shell width and threading then spindle length.


I believe what you refer to as a press fit for the spindle and RH arm is just the tapered square fit and you'll need a cotterless extractor to pull the arm off. The same for the left arm... unless...


You mention "more robust". What do you mean? What was lacking when the bike was new?


I wonder if the LH arm got wallowed out and fell off at about the same time the BB was wearing out. None of these possibilities are well addressed by simple replacement. The arm falling off is an assembly and maintenance issue and the BB wearing out will only be slowed down with a better made BB. Andy

Parts like that are selected to bring the bike cost down to what you were willing to pay..

If frame has a common threaded BB, your choices are many..