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Old 07-12-2003, 01:00 PM   #1
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Default Tires versus grip

Can there be too much grip in a tire?

If I'm using tires with more grip, than I usual use, I find my car become harder to drive. Can this be due to a slightly problem in my setup, and this problem become more pronounced when using better tires? Or is it that simple, that I do have to re-work my setup, when using tires with more grip?

When I'm using tires with better grip, I find that my car roll more, thus being more inert in the corners. I also find it'll have more oversteer.

Comments are appreciated !
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Old 07-12-2003, 01:18 PM   #2
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Default youve got it.

Basically your car oversteers because of the high grip and the car will roll more because of lateral grip.Sometimes its not faster to run a tire thats too grippy,but you can overcome some of the problems you face by a couple of different methods.Springs,sway bars front a castor and rear anti squat.Camber changes also can help.You should try changes one at a time.I would try different springs and maybe sway bars to get rid of grip.Maybe others can chime in too.Hope you figure it out.
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Old 07-12-2003, 01:30 PM   #3
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Basically you've answered your own question, if you setup a car, with a set of tyres that don't have maximum grip you will have to set it up softer. You've set it up so that the chassis is pushing the weight onto tyres to create grip. This means that when you change to stickier tyres you will see excessive roll and some oversteer(as you noted) due to the weight transfer that you needed to create grip with the other tyres. Sticker tyres = Stiffer setup and vise versa. If you have way too much grip it can also cause your car to traction roll in corners. Stiffen the shocks up a bit and it should get rid of the excessive roll and oversteer.

Last edited by fatdoggy; 07-13-2003 at 12:21 AM.
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Old 07-12-2003, 01:31 PM   #4
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personally... no, i don't a tire can have too much grip, (especially rubbers) just look at foam tires on carpet, the cars can still be set-up handle the drivers prefer...

set-up is the key to your oversteer...
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Old 07-13-2003, 12:03 AM   #5
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Thanks for the input. I forgot one important point: Our track have some bumps in it, because of the bad concrete underneath our carpet. So using too hard springs, means bad handling in those bumpy sections. So I cant use too stiff springs, thus I have to use tires with less than maximum grip.
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Old 07-13-2003, 12:40 AM   #6
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Before you ditch the sticky tyres try sway bars. Sway bars aren't usually used on bump tracks but it might work it you only used them on the front. The front sway bar would get rid of excess roll and some foward bite. Overstear could also be tamed by using more front toe in. Smaller front shock pistons might also work but not too small since you need the large holes for the bumpy track. Having a lower rear ride hight will increase rear traction and lessen foward traction so that is also a possibility. I'm sure you could sort the problem with a day or so of tuning.

Last edited by fatdoggy; 07-13-2003 at 01:08 AM.
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Old 07-13-2003, 03:05 AM   #7
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There's a couple of other things to do which can tame a cars handling without changing springs and damping (i.e bump handling).

You can raise the roll-centres, which will give the car more roll-stiffness for the same spring rates (similar to the effect of an anti-roll bar, but without physically linking the two sides of the car). You can adjust caster to change the steering feel, or even change rear toe to decrease rear grip.

If you have an adjustable radio, a decrease in throw or a change in the steering curve to make it milder near the centre can also help - too muck lock and the car can grab, and less lock will often carry more corner speed, so long as you can negotiate the hairpins.
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Old 07-13-2003, 11:47 AM   #8
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Thanks fatdoggy and sosidge. I've already tuned my car pretty good, including roll center, sway bars and castor. The question was more from a setup-concept point; Which concept: Tires with as much grip as possible, and work from there, or some sort of compromise. But as somebody else said, I've already ansverwed the question myself.

Anyway, thanks for the input, I think I might try the readio steering curve trick or a little more toe-in. The car is so close to be as I want and at this point, even a small change makes a huge difference.

Until now, I've been working from the point of view, that the more toe-in, the more powerloss. But I'm only at 1,5 degree, so 2,0 may be the solution.

And about steering curve, I played with when I got my KO EX-11 Presto. I didnt liked it, but maybe I should try with just a small amount. One thing I dont like, is that my manual sais it slows down the servo, it's not only at the centre.... But it's easy to try, so I'll give it a shot !
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