I recently bought a set of Shimano R500 wheels to use as spares/training/turbo use. I got the rear fitted with a 105 (5700) cassette (12-25T). The rest of the bike is 105 (5600) spec, including the chain. I'm running a triple chainset.
It seems to be generating a lot of 'grinding' noise where it contacts with the chain. Mostly happening on the small cassette sprockets (7 through 10). Noisy on the middle chainring, really bad on the large chainring in smallest three cassette sprockets. Shifting throughout the same gears is far from smooth.
My main wheels (Fulcrum 7) with 105 (5600) cassette (12-25T) are working perfectly while on the bike (no grinding).
One thing I should mention is that I got a bike shop to take the 105 (5700) cassette off another wheel I had and fit it to the new R500. They had a problem with the existing spacers (sprockets were loose). They did manage to get spacers from their spares box, but I don't know if they are the official Shimano versions.
Any ideas what the culprit is? Is it a 5600 vs 5700 compatibility issue (i.e. running a 5700 cassette with 5600 on rest of the drivetrain)?