>>1681924remove the pedals with a 15 mm open end wrench (this is easier to do with the cranks still on the bike)
then you will need a 14 mm Hinged Socket Wrench (or a socket with thin walls) to remove the crank bolts
lastly is the use of a crank extractor, thread it into the crank by hand at first, being careful not to cross thread
to guess vaguely for a 21 or 24 speed bike
measuring from the center line of the seat post to the middle chain ring should be about 47.5 mm
your bottom bracket spindle may be around 118 to 122.5 mm wide (likely the latter)
each crank set and bottom bracket type will cause a different offset of chain ring, and width of q factor
good brands have this information available
