[Jeff Chambers]

Depends on a few factors. If your car is only of moderate HP, then there's probably no need to have them screwed to the rims. I run on a 26x8.5-15 slick with about 385HP and I've never had a problem with the tire moving on the rim. I mount the tire with as little bead lubricant (soap) as possible though. It makes the mounting a little bit harder, but gives a firmer grip on the bead.

Balancing is another story. If you've got a 3-piece rim like a Weld, spin balancing is real tough because that center spacer in the rim moves around. Weld actually says that the only way to really balance them is to spin balance them >>on the car<<. Problem is that virtually nobody has an on-the-car balancer any more. Without an OTC balancer, you can static bubble balance them (if you can find someone who does that!). A single piece rim can be spin balanced at any regular tire shop. I've run quite a few pairs of slicks without any balancing at all. At trap speeds of 115-117mph, its never seemed to be a problem. If you're blasting down the track at Pro 5.0 speeds, I'm sure its a different story.