So I'm going to purchase a Trek 4300 secondhand from a friend but the left crank arm (i think its
these ) is stripped on the inside where it connects to the bottom bracket. The inside is a square hole and it looks like its stripped from usual wear and tear, I think the crank arm is aluminum. It wont hold still for more then two seconds (it loosens the bolt) any quick fixes?
Thanks in advance for your help.