Handling Concepts

Here are some things you should know about your car's handling before you make adjustments.

1. initial turn in response    understeer/oversteer ?
2. steady state cornering      understeer/oversteer ?
3. corner exit                 understeer/oversteer ?
4. slalom response             understeer/oversteer ?

• initial turn in response is when you first dive into a corner and the outside shocks/springs are compressing.
• steady state cornering is like when you are going in a circle, holding the throttle steady...
• corner exit is exactly what it says, under acceleration.
• slalom response is what the car is doing on fast transitions, when the spring/shock may not be compressing all the way.

An oversteering condition in steady state corners would be corrected by trying a larger, or stiffer front or softer rear swaybar.

Understeer in transient response (slaloms) may be due to not enough damping in front, or too much in the rear. With the correct suspension setup, the car should react with very little difference between types of corners, regardless of tire pressures. For example: if your car is understeering in a low speed, sharp corner, then it should do the same in a high speed sweeper. However if you then oversteer in long, fast, sweeping corners, then it may be because all 4 tires are rolling over.

If your front tires are what is limiting your slalom speed, your real problem may be your front/rear damping rates, or chassis setup, or tire pressure. You need to keep your tires at a maximum slip angle, without going over. The fastest way through the slalom for you, would be to understeer through it slightly.

Usually, shock settings are adjusted to what the car is doing in certain areas of corners. Turn in, Steady state, Exit, and transient response (slaloms for example). Shock settings get softer for less surface traction. So do my swaybar settings. When it rains, almost everything is set at full soft.

Tire Pressure

From my experience, the RS and RS II Yokohamas need up to 40 PSI in the front to keep a decent contact patch. When I run my A008 RS II's I run them at 40 PSI front, 37 PSI rear. My pyrometer readings read perfect on all 4 tires with these pressures, any less, and I overheat the outside edge.

The Yokohama A008 RS's don't have as stiff of a sidewall as the BFG R1's. therefore you will have to run higher pressures to keep them from rolling onto the sidewalls. Measuring tire temperature across the width of the tire will tell if you are running the correct tire pressure. You should have about the same tire temperature across the width of the tire. If it is hotter on the outside edge, then your pressure is too low.

Where I usually start, is the front tire pressure and suspension. I try to make the front end stick as well as possible first, and then adjust the rear to work with the front. Of course, after the rear adjustments, the front may change, so I go back to the front. Eventually, the front and rear are going to balance out, and I'll have a well balanced car.

On a front wheel drive car, most of the weight, as you know, is on the front end. The key to finding the correct pressures is to find the optimum pressure in the front, and then adjusting the rear pressure to balance the car. That is, assuming that your suspension is set up correctly.

Some people optimize their front pressure, and reduce pressure in the rear to balance the car. Some raise pressure in the rear. Both work, as long as the front tires are getting as much traction as they can.

Even though my car is lighter than the Integra, I find myself running 40 PSI in front, and about 37 in the rear, when running Yokohamas. I've seen other cars run up to 44 PSI in front for the GS-R's.

Try starting with your front pressure at 40 PSI, and rear at about 36 - 38 PSI, then adjust from there. Even if you enter "a curve just a _tad_ too hot", you shouldn't be rolling your tires. It should just be sliding. It's best to be a little too high in pressure than to be too low, as too low can destroy your tires.

I keep an extensive log book on tire pressures and suspension settings for my car, so if anything does change, I can usually make adjustments once, and get it right the first time. No other adjustments needed.

Also, what works for one track, may not work at another (due to differences in surface traction, etc...). This is where keeping a log book is very important. I have a log book for every place I've ever raced at, and I usually set the car up before I get to the event, and only minor adjustments are needed after that.

With race tires, I've seen a well prepared GS-R hit over 1.0 G's on steady state, and spike ( slalom ) over 1.1 G's. For his particular suspension set up, his pressures on his Yokohamas were at 41 front, 37 rear. Your car may vary.