Im fitting a secound hand crankset for a friend and it looks like the crank axle is too long ? I have used the spacers behind the BB bearings as per shimano instructions but still have 3-4mm between the crank and bearing. The crank arm adjuster wont take it up . What am I missing here ?

3 spacers total?

BB shell size?

Is BB a 68 or 73mm and does this match the frame?

Does this help?

http://www.cyclistno1.co.uk/features/maintenance/servicing-xtr-cranks.htm

Were you given the thumb tightened tensioning ring for taking up the slack as shown on the piccy below behind the crank arm on the non-drive side?

I’m assuming it’s an M970?? Edit: PIC above wasn’t there when I started typing! First of all make sure the tension adjustment ring on the non drive-side crank arm is snug to the arm before you put it on. Also when you put the non drive side crank arm on make sure it’s engaged on the axle properly – I often give it a gentle tap with a rubber mallet to get it seated – after checking it’s lined up properly! If it’s not seated on the axle far enough before you start tightening you’ll find you have the problem you describe above.

Have you done it up chuffing tight? It needs to be just a tiny bit less than “shit, this is going to break the tool”.

As above really. Do you have the adjust nut item 4 in diagram.
http://cycle.shimano-eu.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M970-2592_v1_m56577569830608898.pdf

The crank arm adjuster wont take it up

I think he has done that guys.

I had the same thing – are you sure the BB shell really is 68 or 73mm? Some frames that have been faced and re-faced are now too narrow, and extra spacer can help. Thinner spacers that fit can also be found in some old cassettes if you break them by punching the pins out.

I have the no 4 adjuster but it wont adjust anywhere near the distance I need. What is no 5 in the pic ? a spacer(x2) ?

Yip if its not the tensioning ring thats missing I agree with anotherdeadhero with the BB width – measure it?

part 5 in the exploaded diag is the little rubber ring that is pressed into part 4, I think. Not a spacer.

So basicaly just space out the bearing cups then ?

Erm so “I have the no 4 adjuster” – you mean its not that model or you haven’t got the adjuster? If you haven’t this is your problem as the adjuster will give you 2-3 mm at least?

I doubt it’s the spacing of the BB. If there were too many spacers the axle would be too short if anything. If there weren’t enough, then when you tigten the cups down it will crush the internal sleeve and you’d probably struggle to get the axle through anyway.