Park Tool CC-4 chain checker says "all good!" but...
I'd like to think this isn't user error -- it's not like a drop-in style chain checker is a particularly difficult tool to deploy, but I guess that's always a possibility -- so I'm kinda baffled by the results I'm getting.
The chain on one of my bikes has ~3,200 miles on it. The cassette on that bike has over 6,200 miles on it.
Cassettes I can sometimes get more life out of...but usually only if I've been changing the chains every 1,500-2,000 miles.
So purely based on the accumulated miles, I fully expect that I'm due for at least a new chain, if not also a new cassette.
And sure enough, the drivetrain has been behaving exactly as I would expect it to when it's time for at least a new chain, if not also a new cassette.
So far so good, right? Just change the freakin' chain (and maybe cassette) Bob and be done with it!
But I have this Park Tool CC-4 chain checker, and on a whim I used it to check this used-for-3,200-miles chain.
No wear. Not .50%. Not .75%. None.
Da hell?!?!
Is there any possible way to (mis)deploy a CC-4 and get false-positive readings? Or, is it common to have a chain that doesn't register any wear on a CC-4 and yet shifts like crap, because it's actually got ~3,200 miles of use on it? Is this chain checker tool useless, or am I a tool?
Thanks.