i'm trying to overhaul my bottom bracket for the first time but i have come across an odd problem. i have two crank pullers, one is just too big and the other only fits on to the left crank arm. can't figure out why. it is a square tapered crank with the old style bottom bracket not a cartridge type. both the arms are original, matching and havent been replaced at any time.

so my question is this; is it still possible to do bottom bracket maintenance without removing the right side crank arm???

ive been looking forward to this all week and i cant go out and buy a new puller because i can only get them online which takes a while and my guess is that a third crank puller wouldn't fit either.

problem solved. it turns out that both my pullers were the same size, the correct size. after persisting for an hour it eventually went on, no cross threading, nice and smooth. i think that the opening may just have been slightly deformed or something.

To my knowledge, there have only been a few different threads used for crank pullers (and arms) with the most common one accounting for about 95% or more of all cranks. (for a while Campagnolo used a LH version of this same thread).

Odds are your problem isn't that you have the wrong puller, but that the outermost thread of the arm is damaged slightly so you can't get the puller started. take a good look at the RH cranks thread, and if you see any dings, use the tip of a half round or rat-tail file to remove part of that 1st thread (no more) at a 45 degree angle. Then, assuming both cranks are the same brand, use the puller that fit the left crank and you should be OK.

Odds are that the crank arm had some minor damage to the lead threads which can make it hard to thread in the crank puller... unless the crank arms say Stronglight or T.A. the odds of the threads being anything but standard are pretty slim.

With Stronglight you only have to worry about much old cranks as they adopted a standard 22 by 1 threading in 1982 but used a 23.35 by 1.0 prior to this and TA cranks use a 23 by 1.0 puller.

22 by 1 mm is the standard crank thread which was adopted from Campagnolo and is used by most of the square tapered cranks out there... the only other oddity would be some early Lambert cranks that use a 7/8 by 24 tpi threading.