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Cold/ Hot Tire Pressures Michelin Pilot Sport 4S

15K views 12 replies 6 participants last post by  dcharnet 
#1 ·
Can anyone suggest Michelin Pilot Sport 4S cold and hot tire pressure guidelines for a PCA DE at Road America? Air temps will range from 60-75. There might be intermittent rain on one day.
 
#2 ·
Generally speaking, in dry conditions start with 28-30 psi cold. Bleed off air as necessary to maintain approx. 36 psi hot. Adjust to your liking.
In wet conditions, start with factory-recommended cold pressures. The tires won't heat up very much in the rain as the water carries the heat away from them, and the higher cold pressures will keep the rain grooves open to best extract water. Again, adjust to your liking.


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#4 ·
I start at 30 cold and monitor pressure after every session. On warm days, the pressure will increase up to 36-38 after one session. I will bleed out pressure to get back to 33-34. Then repeat. Your driving style, car set up, track and temp will affect the best pressure. Try different hot pressures until you are happy. Just don't go too low or too high, as it is bad for the tires and your lap times.
 
#9 · (Edited)
I think there were 4-5 cars from Great Plains Region PCA running in this event. They always have a good time. Cars would include a gray 09 911 S, a yellow 17 911 GTS, a red 16 Cayman GTS, and a white 15 Cayman S.
 
#10 ·
I had C4,5 and 6 fused with a titanium plate three years ago. Cause was related to ligaments loosening due to osteoarthritis. I lost some minor feeling in the right hand before, but the six month MRI after the surgery, the neurosurgeon told me that the spinal cord was dead center in the canal and that I could not have had a better outcome. He made no limits on track driving, although I only do HPDEs.

Getting back on topic...

My 4s tires on my Boxster heated up 6 to 8 PSI initially at 65 - 70 MPH highway driving (As indicated in the instrument cluster). Gas Mileage was lower by 2 MPG over the Mich P Alpin 4 winter tires I took off. I had the tires aligned after approximately 200 miles. Before alignment, the right rear got 2 PSI higher than the rest. Alignment showed that tire was slightly more out of line than the others. Post align - the tire that increased in pressure when driving moved to the right front, but overall pressure increase has dropped to just three or four PSI on all the tires. Yesterday, after a 40 mile drive, I got 33 MPG, an increase of 1.5 MPG over the most recent comparable drive. I assume the tires are finally breaking in.

V6
 
#11 · (Edited)
My surgeon, like me a serious skier, said "Don't ski the blacks any more, ski the blues." HPDEs are like skiing the blues. Risk is diminished, but it is there. Now that I understand what these events are all about, I may buy the version of the HANS which can be used with the 3-point belt. The Fire and Rescue EMT who tended to me at Grattan said that the HANS I was wearing then probably saved my life. The words, and indeed the memory of the incident, still resonate.
 
#12 ·
My surgeon, like me a serious skier, said "Don't ski the blacks any more, ski the blues." HPDEs are like skiing the blues. Risk is diminished, but it is there. Now that I understand what these events are all about, I will buy the version of the HANS which can be used with the 3-point belt. The Fire and Rescue EMT who tended to me at Grattan said that the HANS I was wearing then probably saved my life. The words, and indeed the memory of the incident, still resonate.
Are you looking at the Simpson system, or from some other vendor?
https://simpsonraceproducts.com/hybrid/hybrid-s-3-point-belt-compatible/
 
#13 · (Edited)
Looking at the Simpson, but open to suggestions.

My only hesitation is wondering whether it is redundant with an air bag system.

That might prevent the rapid forward movement of the neck and skull which, in a car with no bags and a 5 or 6 point race harness holding the torso relatively firmly (even the best race belts give a little with sufficient force), causes the basal skull fracture and spinal cord injury. I was topping 130 at Road America and lapping at the end in the 2:50s. Fast enough to make this topic relevant. Dale E. hit his last wall at 60-70.

Will try to research.
 
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