HPDE and R888R tires

[john42]

Heading out for a solid HPDE weekend @ Palmer. Any advice for starting air pressure in R888R tires. 315/35ZR17 and 275/40ZR17. I'm usually pretty low (18 PSI) for autox. Not sure how that translates to HPDE.

[Dave 53]

I have never used R888R's. I don't see them too often at California tracks. V730's are what most of the cool kids are running on the West coast these days. But, I did have a talk about them with our local track tire supplier (Roger Kraus Racing). At least for my 1,950 pound (at the time) 818, he was saying 27psi hot which is what I start off with on other track tires too. Your car is heavier so a few pounds more might be appropriate. I usually start at about 23psi cold for the first session and immediately check pressure off the track. They are usually over 27, but it's easier to let air out then to add air. As the day warms up and I push a little, almost every session I'm letting a little bit of air out to get back down to 27.

I'm the opposite.... I usually do HPDE and I'm doing my first autocross next weekend. Maybe I should go lower than my HPDE 27psi?

[john42]

I have never used R888R's. I don't see them too often at California tracks. V730's are what most of the cool kids are running on the West coast these days. But, I did have a talk about them with our local track tire supplier (Roger Kraus Racing). At least for my 1,950 pound (at the time) 818, he was saying 27psi hot which is what I start off with on other track tires too. Your car is heavier so a few pounds more might be appropriate. I usually start at about 23psi cold for the first session and immediately check pressure off the track. They are usually over 27, but it's easier to let air out then to add air. As the day warms up and I push a little, almost every session I'm letting a little bit of air out to get back down to 27.

I'm the opposite.... I usually do HPDE and I'm doing my first autocross next weekend. Maybe I should go lower than my HPDE 27psi?


My car is 2200lbs and for autocross I been starting with 18lbs. The chalk marks I make usually align right up with the triangle point at the end of the run. For autocross they likely aren't optimal warm for the first 1/3 of the course. I suck tho and a beginner :-)

[Hoooper]

With R888Rs I run 21 front, and based on friday's session at Sonoma I need to run about 22 rear. I was running 21.5 rear but was getting a slight bit too much rollover. Depending on your setup and track I would imagine you should be able to get away with a little less than me. My car has some downforce and is 2450 with driver and fuel, and sonoma has some hills which can lead to compression assisted traction you wouldnt see on most tracks

[john42]

With R888Rs I run 21 front, and based on friday's session at Sonoma I need to run about 22 rear. I was running 21.5 rear but was getting a slight bit too much rollover. Depending on your setup and track I would imagine you should be able to get away with a little less than me. My car has some downforce and is 2450 with driver and fuel, and sonoma has some hills which can lead to compression assisted traction you wouldnt see on most tracks


Palmer has lots of elevation change as well. I don't have any aero tho. That gives me a good starting point tho! I plan on keeping tabs on the wear markers for rollover after each session. Having a good starting point is great! Thanks. Seemed logical to me my starting point for autox at 18lbs would be way too low.