Creaky drivetrain
 

I have just installed a new 7-speed mega cassette (MF-HG40) and the old IG chain seems to hit high up on the teeth of the cog (rather than between teeth) as the link meets the cog causing a grinding noise under load.

Is this just a simple prob of chain stretch? Could the derailer need tuning?

Shimano recommend a HG50 chain for the MF-HG40 cassette. Can I use a HG40 chain which is cheaper?

I am about to fit 9-speed cranks (FC-M440) can I expect any problem with an 8-speed chain. I know this has been covered a bit but looking for wider opinion.

How old is that chain?
Secondly wonder if u r tighen too much the cassette.
What kind of link are u using? with a 7 sp cassette any 6 or 7 speed chain should work fine (even a 8sp one will)

The cassette was factory installed - I only actually swapped wheels. Don't know what sort of link. The original drive components which I am still using are Alvio - Crankset is IG only. Don't know about chain. The bike is 5-10 years old. A Giant ATX 840.

Statrt with a new chain. I would never put a new cassette on a bike without using a new chain, unless the chain had less than say 100 miles on it. As far as the cranks go, you can use any crank with this set-up.