Tires

[Jay Jacobellis]

Hello All

The question is how many heat cycles / laps / miles can we expect to get out of the Hoosier R60A's. Yesterday was our 7th time at the track we have 26 sessions on our set, 210 laps(not including warm up laps). Our first session was our best and then every time my son went out he said the fronts kept getting worse less and less grip on turn in(push). We tried going up and down on air and wound up with 11 1/2 cold up front 15 rear for the best feel. Raised the rear ride height a turn and got a little better but times were 1.75 off the first session. We have .25deg negitive camber 1/16" tow out in the front rear is about the same as the front . Are the tires done or what else can I do to free the car as the day goes on.

Thanks We love this FST thing we just got some things to figure out.

[Doug FST 5]

At 26 heat cycles I think many of us would find the tires to be going away. Based on the information you've provided about setup I think the tires could have performed better for longer with some changes in that area.

Setup is more than just camber and toe. The front shock droop and sway bar diameter enter into the equation. Similarly, the rear shock droop is a factor.

Its hard to say what settings might be best for your car but I'm not aware of anyone in the series running that little camber in either end of their car. We have roll control only on the front end of our cars. They roll a fair amount. The actual cornering camber of your front tires is certain to be pretty positive. The car is certain to push.

The overall theme to setting up an FST is similar to FV. Get the front end to grip as best you can and set the rear to balance.

Doug FST 5

[jim murphy]

Just curious - do ya'll run toe-out? In F5, we always run just a touch of toe-in and as the car gains speed it becomes 0 degree which is best for top end speed. But in autox we run more toe-out for better turn-in due to slower speeds.

Jim

[Doug FST 5]

It's not at all unusual to run an FV or FST with a little toe out in the front to improve turn in. I'd say toeing out the rear is far less common but I've heard of guys doing it.

Doug FST 5

[jim murphy]

It's not at all unusual to run an FV or FST with a little toe out in the front to improve turn in. I'd say toeing out the rear is far less common but I've heard of guys doing it.

Doug FST 5

Interesting. Whenever we tried toe-out, the F5 would wander at high speed - not fun to hold on to. I would hazard a guess that it is the difference in A arm versus beam fronts.

Jim

[Jay Jacobellis]

Doug,

Thanks for the reply. We are just out of karting and need to learn the dynamic of these cars and besides Bonows basic but very useful info we have nothing to go off of for setup and what changes to make to improve the handling. One thing I can't seem to get info on is what is a good front to rear weight bias, we are at 43.5 percent front 56.5 rear don't know if that's good or bad. In karts that is good and with the symptoms we have I would rotate more weight to the front is this something I should try?

Thanks
Jay

[Jay Jacobellis]

Doug,

I also talked with Jeff from Hoosier and he gave me info on air pressures and camber, I will be adding some camber to the front and changing pressures , he gave me a target hot pressure that we need to look for.

Jay

[Doug FST 5]

The front / rear split in weight you have in the car isn't bad. I think you have more weight in the front than many cars as it is. You'll get the car handling by optimizing the camber, droop and toe. Be aware that if the fronts are shot it may need a new pair to get working right again no matter how its set up.

Doug FST 5

[Jay Jacobellis]

What should I look for in camber and toe F&R. Explain droop and how to measure it.

Thanks again

[Doug FST 5]

The forum doesn't give me an option to send you a PM. Send me one with an email address for you. I'll send you a detailed note.

Doug FST 5

[rgu]

I recall an extremely good discussion of rear droop and jacking on the FV section of this board. I think its worth taking a look at. Our tires create another dimension but they do not affect the validity of the discussion.