Radial tire question

[Mike Rietow]

So, the bias slick's fundamental for traction is its deformation. > High energy losses at all frequencies. So, the bias slick is fundamentally inefficient.

The radial is the opposite, low energy loss at all frequencies. Traction at all frequencies if you can keep it from deforming. Efficient, less rolling resistance. Faster, quicker et's.

The fundamental for wheel speed we've found effective for radial tires is the same as limiting wheel stands. Prolong the period of time the shaft is neutral in, or even exiting the damper/shock main body. We run a two way rebound adjuster on a heavy 2950pd small tire radial nitrous leaf spring car to combat wheel stands. No wheely bars allowed in the class. It lays tracks 275 radial, one teen sixty foot. There's another idea, maybe smaller tire would be easier to manage, deformation. Dunno, be interesting to see who gets there first on a radial.

[Adger Smith]

Mike.
We have been using wheel speed/slippage to go fast in Comp/Modified/Gas classes for 4 decades. At the time those were not bracket classes. We all know bracket guys want a dead Hook. A turn to a turn and a half after the hit on roll out usually produces the quickest ET. Watch this with no wheelie bars and a V-6. The tire slips gets it off the line. The engine stays up on the converter after the hit. Hard to dial.

We didn't have computers back in the early 70's and there was a lot of trial and error to make things work. Ed Wright knows what I'm talking about. He was there, too. Glad to see you guys working on this kind of stuff. That is getting the performance instead of being one of the dead hook crowd.

[weedburner]

Clutch hit control is what you need to make radials work with a stick.

I don't share competitive graphs, but this one had a few problems so I can show it here. It shows what a dead hook launch looks like using one of my clutch hit controllers. 302ci sealed crate engine running the spec tune, 3100lbs. Class doesn't allow radials, so this run is with a 10.5" bias slick @ 18psi...



First problem was not enough delay after the hit, which caused rpm to get pulled down to about 5200 after launch. 5500 is typical.
Second problem was the PP needed to be shimmed a little more in order to control those wheelspeed spikes after the shifts.

Depending on the track/conditions, it's not unusual for the above car to be able to go above 20psi with bias slicks and still dead hook without pulling rpm below 5500.