Track tire pressure for CS and Scuderia

I'm beginning to think that perhaps the age of the tires is a factor in Stradales feeling nervous on the track. Have you ever changed your tires?

 

The Stradale needs a little more negative camber than stock to be comfortable on the track. I don't remember the numbers but I will look it up. Mine was much better after a "racing" alignment.

Or it may just be your alignment is wrong from the factory. Snap oversteer should not happen.

Tire pressure should not go above 35 hot. Probably best around 33 but some others on the board can give you more specific details.

 

Was the tyres warm ?
Was it dry ?
Did you have ASR/CST off ?

Usually what you did up there is bad driving, nothing else, even if cold tyres/ wet conditions will make things worse.

How experinced are you on track ?

 

Next time try waiting until the car is pointed in a straight line before you "pressed to fast and too hard on the accelerator"

 

Not to judge your driving skills, but try driving with the asr on until you've had some instruction on car dynamics.

 

I agree. Nothing wrong with the tyres or car. Use ASR until you can answer your own question. ASR off in a Ferrari is for experinced and skilled drivers only.

 

If you had a Tire temperature gauge (probe tip pyrometer, can be found around $100) you can use it to read the temps of the tires and to setup the suspension alignment for the tires on the car and for the way YOU drive the car. So, for less than 10% the cost of your next set of tires four your car, you can be in a position to KNOW if the suspension is correctly dialed in.

You will be looking for a nice even temperature rise from the outside edge of the tire tread to the indise edge of the tire tread. After a drive of more then 5 minutes in the condition to be tested (several laps), enter the pits without a slow down lap and immediately measure an outside tread block, a center tread block, and an inside tread block, for all 4 tires; write these numbers down. You should expect 10dF to 20dF difference, here, as the outside of the tire is cooled by the air rushing by. After measuring the tire temperatures, you can measure the tire pressures--these change slowly while the tires loose temp rapidly.

Street tires (and r-compounds) in track conditions should come off the track at 180dF to 200dF and with 40 PSI of pressure (all 4 corners optimally). {Real race tires will tell you where they want to run.} Running street tires to hot and they will feel like grease is on the track. Run them too cold and while they don't feel like grease, there just isn't any traction either.

{Assuming a road course with both left and right turns} If the center of the tire tread is hotter than the average of the inside and outside, then you have too much air pressure. If the center is cooler than the average, the you need to add pressure. Get this into the right ball park first.

If the inside edge is too hot (more than 20dF hotter than the outside edge), reduce camber; conversely, if the inside is not hot enough (less than 10dF hotter than outside edge), add camber. Remember, we want to keep a nice 10dF to 20dF temperature gradient across the tire's tread.

If the front tires are not as hot as the back tires, you can add a triffling more toe-in to increase the temperatures on the front tires. Track only cars often use toe-out to decrease tire scrub in turns (and the driver accepts the nervousness this causes). For these cars, you can diddle with the amount of toe-out to balance tire temps front to rear.

Once you get the tires working, you can address whether the suspension needs raised/lowered at the back to address oversteer/understeer, or raised/lowered at the front to adress braking stability.

 

Excellent post, Mitch, Thanks.

 

Heres a good baseline for a CS w/ Pirelli Corsas.
Start at 29 psi cold. After a session bleed/adjust to 36 psi hot.

 

So far all the advice is for a single pressure but factory recommended cold is 32 front and 29 rear.

On new tires at factory pressure my CS understeers a lot. On worn tires it oversteers. Upon reducing the rears to 27 cold and keeping the fronts at 32 cold, it is better but still oversteers. Eventually I spun on a sweeping downhill turn on steady throttle and ASR on.