Hi I just got some new XTR970 cranks off ebay and I am having trouble installing the left non-drive crank arm. If I put the left arm on anf tighten the alloy 8mm allen bolt the left arm only pulls on partially so that half of the splines are still visible even when the bolt seems pretty tight. (45-55Nm specified). The crank splines look fine and for the life of me I can't see any reason why the left arm won't just pull fully up the splines. i tried a rubber mallet to see if that would make the crank home fully seated but it didn't. The arm is still pretty easy to remove after tightening the bolt.
Do I just use a bigger tor

