Chatman

Rain is forecast for at least Saturday morning HPDE at Thunderhill (Willows, CA). I have read mixed opinions about using competition "slicks" on wet and moist pavement. Short of spinning off into the weeds, when do you know to use street tires? Is it only standing water that is a problem?

Sorry. I live in the central valley of CA where it hasn't rained since spring.

Tintin

Actually, the water part is fairly obvious. If you see puddles you need treads. The real problem with any drizzle or rain is that your tires will always be cold so you have to be really careful or you will be doing some agricultural work. I have run Hoosiers on a Mustang Cobra at T'Hill in the mist and it is a little tricky because the tires have low grip in the damp . It is not impossible, but it requires hyper concentration.

You absolutely never want to go off Thunderhill on to the grass/dirt as it is a really super sticky clay that it will take you years to get off the car. I spent 3 years pressure washing my Honda that we used to use for the 12/25 hour when it cut inside one of the turns to avoid a wreck in the rain. It did not get stuck, but that stuff is like bathtub caulking for goo content..

I would take a set of road tires with me if I were you and work up to speed if it rains. Rain driving is really fun and enlightening. Enjoy!

Here is the Honda, you might remember it:

Bill Hetzel

Even grooved slicks won't push much water out from underneath and they'll spin fairly when you're trying to get the power down. And T-Hill does have a few placed where it's easy to go off when it's wet.
But, I'd rather run T-hill in the wet than Laguna.
The forecast here is a.m. showers and we're further to the east. You may luck out.

Tintin

So how did it go?