brand new isis crank coming loose ?

i have just got a qu-ax 24" muni with isis cranks , today was my first ride on it and the left crank has come loose . (i also had this problem with my qu-ax 20" freestyle with normal cranks?) any advice as it cannot be broken as it is less than a day old :thinking: btw its a Qu-Ax CrMo Red ISIS 48-hole Hub

Do you have a crank puller tool?
I would remove the crank (or both), thouroghly clean the whole contact area of both the crank and spline and put them back on and hit them with a rubber mallet while supporting the other side with wood so you dont really mess it up.
I have heard new cranks often need to be banged on and tightened a few times before they are seated well.

Tapers are held apart by tiny imperfections

Both square tapers, and ISIS spline cranks should be driven on. Grease the crank (to exclude water), then place the uni sideways on a solid piece of wood. Put a 2x4 over the crank to prevent smash marks. Beat the crank onto the taper with a hammer before you put the bolts in. This makes the contact patch between the cranks and hub much larger, and gets it on much tighter then the bolt alone can.

Hammered on? :astonished:

I doubt that’s necessary and wonder if it’s damaging to the cranks and/or hub. I’ve never needed to hammer any cranks on, and I’ve put plenty of miles on square taper and ISIS cranks. With ISIS cranks, I’ve just tightened the bolt before every ride, and after a few times it stops coming loose so often. You can use blue loctite to keep the bolt tight too.

I had the same problem with my Qu-Ax Cross. Just keep tightening the crank bolts before each ride and soon they will settle and not need to be tightened as often.

I usually do this routine whenever I take the cranks off for what ever reason.

Also, check the cranks are on the correct sides / check the pedals are on the correct sides.


There’s no need to hammer on ISIS cranks. Just grease the interface and tap it on gently until the axle bolt threads catch. Tighten to firm hand pressure and check it regularly. ISIS crank bolts usually come slightly loose on the first few rides on a brand new uni - that is normal. Over time you’ll need to do it less often but you will always need to check bolt tightness on your uni fairly regularly, as part of regular maintenance.


its fine now , has been cleaned and my dad tightened it until he couldnt move it ay more , will keep checking it every ride , thanks for all the help :smiley: