High Gears slipping under load

BillB Can you strip the rear cassette down and re assemble it with the cogs flipped round so you are now driving against the other (un-worn) side of the teeth. Quite a bot of hastle but if you don't want to spend any money it may work.

Cassette cogs run on a splined freehub body, the splines (and matching notches on the inside diameter of the cogs/sprockets) will only go on one way, flip them and the splines/notches will not match up.