whats the different between the Shimano IG models say like Shimano IG 31 and Shimano IG 90? I cant see the difference other than color and price

The number that follows the IG indicates model and the higher the number, the better the model. So the IG 30 model isn't as nice a unit as the IG 90, which will last longer and be easier to clean. They should however work the same when brand new.

Chuck

I have the IG90. Got it on sale for $18 at Performance. Can't say it's that good ... it rusted after my last muddin' session, even though the chain's supposed to be cadmium plated? :confused: Otherwise a very nice chain. I have almost 500 miles on it and it still works like new.

I have an 8-speed STX drivetrain.