My Citation hates American Racers, loves Hoosiers.

[avt007]

Hi guys, Our group switched to ARs this year. We ran the first two races on whatever we had (Hoosiers for me) then went to ARs. My car went from being very stable, predictable, and neutral, to oversteering badly, not a great turn in, and generally not great.

The transformation is amazing to me. To cure the oversteer I dropped the rear ride height 3/8 of an inch. Running without the rear antiroll bar seems to help a bit as well, but the lap times on new ARs are slower than my Hoosiers from last year. How can tires be so different?

The next race is in two weeks and I'm not sure where to go next. I have done corner weights, but forgot to check if the chassis is level.
So off to the garage to check that, but I need to come up with a plan of what to try next.

Rob

[Rick Kirchner]

I had the same experience with a 94 VD FC when I moved to the Southeast for a few seasons. Could have probably made them work with some testing, but without crew and nearly every track a new one, hard to separate chassis changes from gaining experience, coupled with fatigue, etc.

I'd guess the best way to make the car better would be a dedicated test day on a track you know well, with a couple of guys to help, running just a few laps between changes and some data analysis if you have that capability.

I seem to remember the ARs being fairly consistent for something like a dozen cycles after the initial drop-off.

[Steve Demeter]

I think in general Citations tend to be easier on tires than most other cars. Therefore switching to the harder AR's might mean that you have to get the var to work them harder to get the temps up. Just MHO.

[John LaRue]

A new tire often requires a new set up. Aside from being a different compound you are most certain to have different spring rates and construction front and rear. They may require more or less camber; I recall that someone was running positive camber to get those things to work when they tried them as a tire in FB/F1000. You will also need to survey toe, rake, spring rates, and aero. If I find my notes from when we were investigating tire options I will post them.

[DanW]

We ran these tires in Club Ford for years. They are harder compound than the Hoosier R60s and ran them with starting pressures at 11 Front and 13 Rear with a target of 18 hot.

The rear tires' sidewalls are very, very flexible. One had to look carefully at the inner sidewalls to make sure the sidewalls didn't contact the uprights or the rod ends under hard cornering. The rim actually moves 2+ inches laterally within the tire and actually grows in diameter like a drag tire as you go down the straightaway.

[avt007]

We ran these tires in Club Ford for years. They are harder compound than the Hoosier R60s and ran them with starting pressures at 11 Front and 13 Rear with a target of 18 hot.

The rear tires' sidewalls are very, very flexible. One had to look carefully at the inner sidewalls to make sure the sidewalls didn't contact the uprights or the rod ends under hard cornering. The rim actually moves 2+ inches laterally within the tire and actually grows in diameter like a drag tire as you go down the straightaway.

The local wisdom is very similar that the ARs slide a lot and you need to get used to the back end coming out.

[DanW]

The local wisdom is very similar that the ARs slide a lot and you need to get used to the back end coming out.

Completely agree, but before the rear tires start to slide, the wheel moves laterally inside the tire, especially left/right or right left transitions. It takes a few sessions to get used to the mambo going on behind you.

[fleetdude]

this is why the impulse to change tire rules, where ever it comes from, should be resisted. a different brand, always claimed otherwise, will change things and will require track time to sort out. we are talking club racing here, and most of us do not have the time and money to sort out a new chassis set-up. clubs and sanctioning bodies: whatever your tire rule is, leave it alone...and if guest racers have been running something different, don't deny them. if someone on a different tire beats you, you have an excuse!

[stonebridge20]

My experience with AR tires is limited to mounting and balancing a set of FF tires for a customer a few years ago.

Just mounting them I could tell that they were garbage.

I can't imagine actually running on them.

[avt007]

this is why the impulse to change tire rules, where ever it comes from, should be resisted. a different brand, always claimed otherwise, will change things and will require track time to sort out. we are talking club racing here, and most of us do not have the time and money to sort out a new chassis set-up. clubs and sanctioning bodies: whatever your tire rule is, leave it alone...and if guest racers have been running something different, don't deny them. if someone on a different tire beats you, you have an excuse!

Availability and the huge price difference between the two drove the change. We are trying to get more people out by choosing the less expensive tire. Some guys (VDs) are flying on the ARs, but I'm still half a second slower than my used Hoosiers from last year.