Pulley Diameters

Not trying to hijack C but chasing a "similar problem".
Rob what is an accepted difference/variance?
I checked factory service manual cooling section ....nada...smallest section in manual lol.

Sorry for hijack

Not a hijack. Please continue as I think this may help more members than just us. I've read a ton of threads on heating/cooling & I don't recall seeing much info on pulley diameters, etc.