Even with no lube for the 20,000+ miles (I think I ran it 23,000)I ran my set I didn't have to swap them yet. Even the chain wasn't really bad just starting to need adjustment more often. On my old bikes with std. chain I used to have to take a link out a couple times before I swapped it out. I hadn't removed a link from my old one yet. Like Bill I bet my rear sprocket would have gone well over 40,000 miles and may eventually go back on. I think I'll just slap a new chain on next time and see what happens, I was just taught never to do that so I changed as a set.
