Cottered crank. There is a wedge which slides across that flat and a corresponding flat on the crank arm. The wedge has a threaded end and you tighten a nut to pull the wedge tight between crank arm and BB
SaidUnderWhere789 on
Yes, replace with a more modern cartridge bottom bracket and square-taper aluminum cranks IF you can get good used parts at non-retail prices at your local bike co-op. Otherwise, cost might be prohibitive for a bike of the age and condition that the photos hint at.
3 Comments
Standard BSA “English” cottered.
Cottered crank. There is a wedge which slides across that flat and a corresponding flat on the crank arm. The wedge has a threaded end and you tighten a nut to pull the wedge tight between crank arm and BB
Yes, replace with a more modern cartridge bottom bracket and square-taper aluminum cranks IF you can get good used parts at non-retail prices at your local bike co-op. Otherwise, cost might be prohibitive for a bike of the age and condition that the photos hint at.