rattling tiagra cassette
my new bike has a 9 speed tiagra cassette, 12-25T. On its first ride it sounded like the mechanic had left some spanners in the frame. Further riding revealed that the rattle was much worse when the chain was on the 6th 7th and 8th cogs. With the wheel in place these wobble slightly, unlike the rest of the cogs. Is this normal, or should the whole cassette feel tight?