I have about 2,500 miles on an LHT purchased six months ago.
On a ride last weekend, I experienced a little chain skip and auto shifting while mashing up some small but steep hills.
I figured in was time for a new chain. I purchased a SRAM PC971 9-speed chain, the same one that came on the new bike. I was prepared to cut it to fit, but right out of the box it was just slightly shorter that the chain I had removed -- not quite a link shorter.
I installed it and test rode it, and it still skips when I mash the cranks on the middle chain ring and the 11 or 13T cog on the cassette, a Shimano CS-HG50.
I'm sure the chain is threaded right. I see no obvious wear on the cogs.
What are your thoughts?