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More Tire Pressure Questions...Need Advice Managing TP

204
243
Exp. Type
HPDE
Exp. Level
3-5 Years
Virginia
I noticed something over the past 2 weekends that confused me a bit. At CMP in July I started with 27 cold (Toyo RR) and tried to keep TP under 36 PSI. This required me to drop TP. about 3 lbs... due to the high track temps/ambient temperature it felt easier to get temp to a sweet spot after a couple laps and go. At the other end of the spectrum VIR in November on a different tire GY F1 3R. At 27 cold tires were sketchy for 2 laps, were great lap 3 but, tire would jump to 36 by lap 6 and start to fall off. I bled down 2 psi and got them down to 34-35 but, felt I was still not benefiting from all the tire had to offer vs starting out maybe too low (best laps of the weekend were laps 3 and 4)? The cold temperatures made it a little confusing and more hazardous. Also confused on if added grip from 3R or my driving style was accelerating tire pressures as it was easier to manage TP on the Toyo RR in hotter conditions? I'm not very fast...2:08s/9's on clean laps, when I'd come off track I was about 2 psi higher than my track buddies running the same car, tire and similar lap times. I felt like I wasn't overdriving the available grip.... Any help would be greatly appreciated.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
7,000
6,142
Exp. Type
Time Attack
Exp. Level
20+ Years
Blair, Nebraska
You are experiencing the arcane science of tire pressure and management, and it is why Race Teams worldwide have Blacksheep 1s as an integral part of their group. Talking to Bobby Archer, years ago, he was telling me about tire pressures at Mid Ohio ( Viper Event we were both running ) as I commented to him about running completely different pressures on my Viper than what the Michelin Rep suggested. As I was running 5 seconds ahead of the other 25 cars in my Class he simply said , you got the pressures right, they got them wrong. He went on to tell me about the pressures he ran on his Hoosiers and I was surprised they had different pressures side to side. He further explained that he had notes for practically every track he ran, because the pressures often varied , and at times quite a bit. We all have the benefit of having folks on here that do a lot of testing ( DaveW, Dave_W, Fabman, Flyhalf, AZBoss, and Blacksheep 1 ) to name a few and the comments I believe we all need to soak up are:
1. What track were they running ?
2. What was the track surface?
3. What were the weather conditions?
4. What brand tire were they running?
5. What tire size were they on?
6. What temperature seemed to work knowing a lot of these parameters?

Hmmm, damn, that is a lot of info to collect and .................that is why it is not a simple exercise and why listening to those who have a lot of experience is super helpful. Now throw in the fact that there are new tires on the market, and current " Hot Brands " change their compounding with no notice, it all comes to fruition that this is a mysterious , and yes, arcane, art to master.

I found, running at Topeka , that the Toyo RRs worked better during the race starting fairly high during the morning race on a cool day ( 60s ), but in the afternoon they needed to start with more pressure. Yep, same track , same day, but even though we all know tracks can change during a single day, we often do not think to change pressures. After 41 years playing on tracks or running in between cones , I have not completely figured it out, but I also have never stopped asking questions.

I think, comparing two different tires and two different tracks , with different conditions can be pretty futile, but the good thing is someone on here will likely tell you what worked for them at VIR with the same tires , and comparing notes is what you will continue to do, because this is not a static situation.

Keep trying , take in all the information you can every time you are at the same road course/autocross surface and actually do what Bobby Archer mentioned to me 20+ years ago --- take notes.

By the way, the Michelin Rep told me my pressures were wrong until he saw my times, and then he told everyone to try bumping the front pressures. I did end up winning my Class ( heh, I was young then, ha ) , but only by 2 seconds as everyone improved. Was I smarter, no, I just had a nasty push and I tried an old autocross trick before the advent of killer shocks, etc. I just pumped up the volume ( in the front rubber donuts ).

From the times you have posted JetOne it appears you are doing pretty darn well figuring things out, as you have clicked off some quick laps at the tracks in your area.
 
204
243
Exp. Type
HPDE
Exp. Level
3-5 Years
Virginia
You are experiencing the arcane science of tire pressure and management, and it is why Race Teams worldwide have Blacksheep 1s as an integral part of their group. Talking to Bobby Archer, years ago, he was telling me about tire pressures at Mid Ohio ( Viper Event we were both running ) as I commented to him about running completely different pressures on my Viper than what the Michelin Rep suggested. As I was running 5 seconds ahead of the other 25 cars in my Class he simply said , you got the pressures right, they got them wrong. He went on to tell me about the pressures he ran on his Hoosiers and I was surprised they had different pressures side to side. He further explained that he had notes for practically every track he ran, because the pressures often varied , and at times quite a bit. We all have the benefit of having folks on here that do a lot of testing ( DaveW, Dave_W, Fabman, Flyhalf, AZBoss, and Blacksheep 1 ) to name a few and the comments I believe we all need to soak up are:
1. What track were they running ?
2. What was the track surface?
3. What were the weather conditions?
4. What brand tire were they running?
5. What tire size were they on?
6. What temperature seemed to work knowing a lot of these parameters?

Hmmm, damn, that is a lot of info to collect and .................that is why it is not a simple exercise and why listening to those who have a lot of experience is super helpful. Now throw in the fact that there are new tires on the market, and current " Hot Brands " change their compounding with no notice, it all comes to fruition that this is a mysterious , and yes, arcane, art to master.

I found, running at Topeka , that the Toyo RRs worked better during the race starting fairly high during the morning race on a cool day ( 60s ), but in the afternoon they needed to start with more pressure. Yep, same track , same day, but even though we all know tracks can change during a single day, we often do not think to change pressures. After 41 years playing on tracks or running in between cones , I have not completely figured it out, but I also have never stopped asking questions.

I think, comparing two different tires and two different tracks , with different conditions can be pretty futile, but the good thing is someone on here will likely tell you what worked for them at VIR with the same tires , and comparing notes is what you will continue to do, because this is not a static situation.

Keep trying , take in all the information you can every time you are at the same road course/autocross surface and actually do what Bobby Archer mentioned to me 20+ years ago --- take notes.

By the way, the Michelin Rep told me my pressures were wrong until he saw my times, and then he told everyone to try bumping the front pressures. I did end up winning my Class ( heh, I was young then, ha ) , but only by 2 seconds as everyone improved. Was I smarter, no, I just had a nasty push and I tried an old autocross trick before the advent of killer shocks, etc. I just pumped up the volume ( in the front rubber donuts ).

From the times you have posted JetOne it appears you are doing pretty darn well figuring things out, as you have clicked off some quick laps at the tracks in your area.
Thanks Bill! Funny you mention auto X I use to go out on some crazy high tire pressures just to keep the outer tread and sidewall alive. I could never get enough camber dialed in my old fox body or understeer out without handling becoming a mess.

I've always been analytical...maybe to a fault (ask me about my golf game). My thoughts in the spring when I return is to go out at around 25 psi cold and adjust lower if need be. Next morning air back up and repeat. I plan on running the same tire all next year...My guess is the tire will stay longer at their potential around 33 hot. I need to invest in a pyrometer too.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
7,000
6,142
Exp. Type
Time Attack
Exp. Level
20+ Years
Blair, Nebraska
If tire pressure settings were real, Racing Teams would not need the Blacksheep 1s of the World. After 41 years at the track or autocrossing I am still asking folks about tire pressures because it can be dependent on so many things. Getting it right is tough, but we are blessed on TMO to have some real Tire Scholars, whether for the track or the autocross.

Take notes at the track and never stop asking questions!
 
204
154
Exp. Type
Time Attack
Exp. Level
Under 3 Years
Bulgaria
If tire pressure settings were real, Racing Teams would not need the Blacksheep 1s of the World. After 41 years at the track or autocrossing I am still asking folks about tire pressures because it can be dependent on so many things. Getting it right is tough, but we are blessed on TMO to have some real Tire Scholars, whether for the track or the autocross.

Take notes at the track and never stop asking questions!
Best and only way to do is to have a pyrometer and take cold temps from the tire and record them after each session with the ambient and track temps as well. And once you figure out your hot pressures just let the car sit with race tires overnight then next morning take cold pressure and this is your starting point for the day. I'm surprised that this is not heavy discussed here as taking right measurements and correct PSI cold/hot is detrimental to tire life and lap times.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
7,000
6,142
Exp. Type
Time Attack
Exp. Level
20+ Years
Blair, Nebraska
bnight, good concepts and again part of the overall , plan, but weather can change from one day to the next, and the track itself can change, so your thoughts are valid, but like all the items discussed there is not a completely simple science. Listening to guys like Blacksheep 1, while at a road course, the changes are often too complex for the weekend racer, but doing what you suggest is just another part of the tricky equation. I think we will all continue to discuss this area for years and years to come ( since tires and compounds change so often ), but there are plenty of members here offering their ideas and experience, so many will get a better feeling about what is working for them. Thanks for offering your analysis, as I think many will take your thoughts into consideration with the other comments given.
 

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