At the co-op where I volunteer we often see wheels, mostly rear, that have bent axles. We are thinking that if we had a few new ones in stock that we could save these wheels for a far cheaper price than a new or used wheel. What axle sizes are common? We see a lot of low end mountain bikes, and older (70 and 80s road bikes). QBP has a page of axles available, but we do not have the expertise to know which ones we need. Thanks for your help.

Regards,
Steve