The have changed the metal since the first production in 03. I had a pair of 03 cranks and the middle chainring wore quickly but Shimano gave me a replacement. I got some on my 04 bike and never changed the ring. I've been running the same set of chainrings since early 06 on my current bike and the rings are in great condition! :thumbsup:HarrisJ said:Crank arms are great, but the rings will wear faster than XT. You can purchase a whole new XT crank for the cost of replacement XTR rings. XTR 950 cranks are a better value as they use standard spiders.