Like Chip mentioned, I bet the guys that go faster with radials either have a rim that's too narrow or the sidewalls are dead......

Think about it........If neither tires spins, why would one be quicker than the other? It's, obviously, the sidewall........If radials were so great, you'd see them in Stock Elimantor (yes, I know a lot of them run a radial slick)........

So, to have the same ET with slicks (which is typcially more desired because it is the more forgiving tire), the sidewalls need to be stiff, which means 2" wider rim than tread width along with the correct, higher, air pressure.........and tubes help stiffen the sidewall too.........and you're not going to be able to run slicks to the cords like so many people do.........

We'd actually change the tire pressure in 1/4-1/2LB increments on Top Fuel cars to control how fast the car gets up on the tire and to control tire shake........If the track is really good, we'd lower the tire pressue 1/4-1/2LB so the sidewall wasn't as stiff so it would sling out and get up on the tire quicker to keep it from shaking.......If the track was bad, we'd raise it 1/4-1/2LB to stiffen the sidewall to prevent shake because we couldn't hit it as hard with clutch because it could blow the tires off....... 1/4-1/2LB doesn't sound like much, but with a tire that big, that's quite a bit of air.......

Even weather effected how much tire pressure we ran.......Bad air meant lower pressure because power was down, so it would get up on the tire easier/quicker........