Throw on some ankle weights...takes alot more effort to move doesn't it?

You have to determine what you're willing to spend and how much you're willing to throw away. You can run a 8.5lb magnesium SSR Comp on the street but the first pot hole or road plate you encounter will make it look like a melted clock in a Salvador Dali painting. Tracks normally don't have those obstructions therefore it's safer to run a lighter more malleable wheel.