I just read (elsewhere on Moparts) that the difference between a steel wheel and an aluminum wheel, the same size, was about 5-6 lbs each. That adds up to about 1/2 your added weight.

Of course the type of wheel will make a difference as well, a cop 15 x 7 is a lot heaver then a 5th ave 15 x 7 because the cop wheels are thicker material. I'm sure different aluminum wheels are lighter then others. I suspect a much bigger difference between a light weight aluminum drag race wheel and a cop car wheel exists then the difference between a standard issue 15 x 6 steel wheel and an old aluminum slot. Gene