how do i take off xt hollowtech cranks? cheers

That was a brave user name…

This should help:

http://www.parktool.com/blog/repair-help/external-bearing-crank-systems-hollowtech-ii-megaexo-giga-x-pipe-x-type-campagnolo-ultra-torque

Just undo the two pinch bolts on the NDS and then the cap. NDS crank will just slide off, and then so will the DS crank with the chainrings and axle.

EDIT: a rubber mallet may help.

and then so will the DS crank with the chainrings and axle.

I had to give the axle a bit of a bang to get it out tbh

Slacken the 2 allen bolts on the non drive side
Flick up the little plastic bit in the gap
Undo and remove the preload on the non drive side (Black plastic round bit in the middle)
Ease off no drive side arm
Tap (Whack)the BB axle with a plastic mallet and pull out
Job Done

All the above posts are assuming you actually mean Hollowtech II cranks – if you have older Hollowtech (One?) cranks like you say in the thread title, ignore all the above.

Undo the 8mm crank bolts at the axle ends, screw in a crank extractor, and tighten it up to remove each side… Very easy, if you have the right tools…

Above advice is all correct assuming you mean Hollowtech 2

Older cranks were Hollowtech arms with an Octalink bottom bracket, in which case you need a crank extractor tool: http://www.parktool.com/blog/repair-help/crank-removal-installation-isis-drive-or-octalink

e: beaten by kaysee!

I’ve still got XT Hollotech I cranks, and they have a self extractor thingy built into the crank. You just need to back them off with an allen key of the right size. IF they are stuck fast, then the soft alloy self extractor can get mangled, in which case you need to take them out(one of those two pronged tools needed here – I made my own with a couple of nails in a bit of wood!)and use a traditional crank extractor in their place

Same as all HTII setups:

http://www.cyclistno1.co.uk/features/maintenance/shimano-ultegra-hollowtech-ii-crank-service.htm

However HTI as above use a crank extractor tool.

thanks everyone, i did it 🙂