Treaded to Slicks

[reisertracing]

Being new to CF, what adjustments do I need to make to the car to go from Vintage treaded tires to slicks?

Thanks

[Lotus7]

Assuming you are switching to scca legal slicks, which are radials, as a minimum you'll want lots more camber, like 3-3.5 degrees vs 0.5 degrees, and you'll also want to check ride height due to diameter differences. Radials want slightly higher hot pressure.
Secondary changes once you've driven it may be spring and bar rates.

[DanW]

Being new to CF, what adjustments do I need to make to the car to go from Vintage treaded tires to slicks?

Thanks

What tires do your local groups require? Most spec Hoosier R60 or American Racer (Mcreary) bias ply.

[AlanVDW]

NEDIV CF Rules are: "Tire choice is restricted to three (3) racing slick options: Goodyear 600, Hoosier 60, American Racer AR133."
I believe all are bias ply.
I went from slicks to the treaded Hoosier VFF (due to cost), which are now legal for CFF in the northeast. If you run on the SCCA spec radial, your in FF.

All I did was take out the camber to run the treaded VFF tire. Just add camber and you should be OK to run slicks.

[Jake King]

NEDIV CF Rules are: "Tire choice is restricted to three (3) racing slick options: Goodyear 600,Hoosier 60, American Racer AR133."
I believe all are bias ply.
I went from slicks to the treaded Hoosier VFF (due to cost), which are legal for CFF in the northeast. If you run on the SCCA spec radial, your in FF.

All I did was take out the camber to run the tread VFF tire. Just add camber and you should be OK to run slicks.

There are also some differences in tire diameter. I believe the front treaded tires are ~7/8" taller and the difference in the rears are marginal. May need to adjust your front ride height to match the rake you run with the treaded tires.

[AlanVDW]

Yup. Jake's correct. The front treaded tires are about 3" larger, and the rears are about 1.5" larger, in circumference. I thought my Lime Rock gearing seemed a bit tall, although I was really slow anyway after 12 yrs off. So, my car may be taller, but I will still need to check the rake. I only changed camber to 1/4 degree negative, readjusted the toe, and increased the tire pressure to run the treaded tires.

[Roux]

Being new to CF, what adjustments do I need to make to the car to go from Vintage treaded tires to slicks?

Thanks

If you are going to the classic CF bias ply tires, not huge changes. People like Jake King, the Kinghams, Dave Harmison, ... all can help you.

treads to radials is a huge engineering transition, unless you are ok with just having fun and the car not being dialed all the way in


Radials = FF = Finicky
Bias = CF = Fun
VFF treads = Super Fun! and should be allowed in any event where the car is elligble. (My opinion)

Steve

[scott fairchild]

Like anything else in racing, it depends on the application. Having had a few cars go from slicks to treads, there were some where we experienced undesirable roll center migration. Once we were able to pinpoint the problem, we could adjust for it. Most cars get away with it just fine with minimal adjustments to things like ride height and camber. It would stand to reason that going from treads back to slicks could present the same challenges with certain chassis.

Good luck with your conversion,
Scott