Front Mech, Crankset replacement

randoneer
randoneer Posts: 27
edited September 2013 in MTB workshop & tech
I have an 07 Hardrock http://www.specialized.co.uk/gb/gb/bike ... disc#specs

I'm looking at putting a XT 10 speed rear derailleur to make a 3 x 10. Would my existing
'Truvativ ISO Flow 3.0 for Power Spline, replaceable rings' crankset and 42S/32S/22S chainrings need replacing or would they be compatible?
Cheers.