Removing the crank arm (square taper) on a Chinese (PooBoo D 577) stationary bicycle In trying to remove the crank arm, I found that the threaded &quot;business end&quot; of the standard crank arm puller has a smaller diameter (1-2 mm) than the crank arm opening, so there is no way to engage the threads.  Does anyone know of a crank arm puller that has a larger diameter threaded end?
It sounds to me as though the crank arm may well be threaded to the old french standard of 23mm as used on old Stronglight and TA chainsets, rather than the standard 22mm which is used by Shimano, Campagnolo, etc.
There are still crank pullers available for 23mm chainsets, I have one from VAR, since I have a couple of old TA Cyclotouriste chainsets on a couple of old bikes. The VAR puller is available from this location.
(I make no recommendation, as I have not used this supplier, other suppliers are available, Your experience may vary, etc...)