Replacing entire group - need new hubs? My commute bike has been in daily use for 15 years. It was built with XTR components but it seems that they don't make chainrings for this crank anymore. It has come time to replace the rings (3rd set) again but Im guessing that I need new cranks.

The rear derailleur is 9 speed and it doesn't seem like there are so many of these anymore so I'll probably end up replacing everything to get modern equipment.

With that in mind - can I put a 10/11 speed cassette on my existing (15 yr old Chris King) rear hub? Or does this need to be replaced also?
With that in mind - can I put a 10/11 speed cassette on my existing
  (15 yr old Chris King) rear hub?


9, 10 and 11 speed Shimano MTB cassettes all use the same freehub body, you can keep the old hubs.


  It has come time to replace the rings (3rd set) again but Im guessing
  that I need new cranks.


Given a 15 years mark, you run FC-M950 or FC-M952. If that's true, try looking for an aftermarket directmount spider that accepts more readily available chainrings. Personally, I find it quite cool to own one of a kind crank like that.