I replaced a well stretched chain last weekend it was well over the .1 on my Park chain checker and riding to work this week the chain slipped in the 2 small cogs at the rear when in the lower ring at the front.
The was cassette fitted in July/August 11 and think it's got about 2.5-3K miles on it. I bought my Garmin last June and since then it has recorded 1900 miles on it.
Looking at the cassette it doesn't look significantly worn. I've also noticed that the new chain is rubbing on the rear mech when on 36 / 11. So could it be the chain is too long or should I just change the cassette (I've bought one) and keep an eye on chain stretch in future?