Originally Posted by HillRider
I agree that 500 miles is unusually soon. Carefully measure the distance between 24 pins with an accurate ruler. if it's more than 12-1/16" your chain is noticably worn. The Park and Rohloff chain checkers are notoriously inaccurate because the premise behind their design is flawed. Use a ruler.
I think we're in agreement that OP's probly being taken, but the contention that these gauges are "notoriously innaccurate" I think mistates where the mistake lies. Its in the hand of an inexpirienced user, though a simple tool it is, where mistake is made. Unless there is some article from a reputable source on this claim, I would contend that while rivet measurement is best, the Park chain-checker is plenty accurate to guage whether a chain should be replaced.