crank bolt not reaching thread!

nick19nick86

Hi, I am unable to put the drive side crank on at the moment as the crank bolt doesnt reach the thread. I've tried using a mallet but there is only so far I can get it on. the crank bolts are m12 and for an isis fsa platinum pro bottom bracket. There is 12mm of thread showing on the bolt, and I think 15mm would get it on. Have been down my local bike shop but they dont have anything longer, and the hardware shop also didnt have what Im after.
Any help would be much appreciated as its doing my head in.

nicklouse

so what are the cranks?

nick19nick86

The cranks are fire eye cmc isis, bought recently as well as the bb. The left side crank arm wasnt a problem to get on.

nicklouse

ok then, try fitting the left on the right and the right on the left.

this will show if there is a problem with the cranks or the bb.

nick19nick86

ok cheers, I will go and try that.

nick19nick86

The left hand crank arm did fit on the drive side, but i couldnt get the bolt in the left side with the drive side crank arm. So I know the bb is alright.
I held both cranks off the bb and in my hands and put the bolts through them up to the splined bit and realised that the drive side splined bit in the crank arm is slightly longer.
So I think I just need a slightly longer bolt.
Guess I will just have to look out for longer m12 crank bolts.

nicklouse

OR the splines are damaged on the drive side arm.

but if it is fitting/seating correctly then yes you need longer bolts.

nick19nick86

I think the splines are fine on the drive side arm as they do go on, its just finding longer bolts which might take some time.

MarvintheAndroid

The bolts are probably fine pitch, you could try taking one to a few motorcycle shops and see if they have anything as motorcycles often use fine pitch threads.

Marv