Are you replacing same size rim (15" for 15", 16" for 16")? Are you replacing the rim because you hit something (like a pothole)? If so, there may have been damage to the wheel assembly or suspension your weren't aware of. You may also want to have the new rim and tire spin balanced, if it came from a salvage yard it may have lost a balance weight. You should also confirm new rim is the same offset as the old rim, if it has too much positive offset it may be contacting some part of the wheel assembly/suspension. (I don't think this is your problem but just want to cover all bases.) You also want to check new rim is clear of all debris, even a little caked dirt on the inner rim and make tire seem unbalanced. Try jacking car up and spinning new rim by hand, does it rotate free and clear?
