I've just replaced the cassette on my hybrid commuter (replaced the chain a week ago and found that it skipped on my most-used sprockets).
As this bike is no longer my main bike, and it takes 8 speed cassettes, I thought I'd try a cheap compatible one. The hub is Deore and about 6 years old, and I've used a few Shimano cassettes since fitting that wheel.
But this time, when I tighten the lockring, the freehub doesn't feel right. Torqued up really hard it felt quite stiff, so I took the cassette back off and made sure there was nothing out of place. I might have done it up a bit less the 2nd time and it felt better, but still not perfect. On the bike, it feels normal when riding, even freewheeling, but pushing it the pedals go round. BTW I don't normally go for the full stated 40Nm, or use my torque wrench for cassettes.
What's likely to be the cause, and how worried should I be?