[ItalianZL1]

I am instructing this week-end at Roebling Road with the Porsche club and will be taking my ZL1 out on the course for a few sessions.
Any advice on ideal hot pressure on OEM tires?

[nikerret]

On my SS1LE w/stock tires, I start at 26-28 PSI, depending how hot it is outside. This ends up with on track PSI from 32-35. The tire temp monitor at the end of “Normal” or the beginning of “Warm” is when I’ve had my best laps.

Your ZL1 is a little heavier, up front. Keep that in mind.

[TransamGTA350]

In my SS1LE:

For a 15-20 minute session, I generally go out at about 28psi and target hot pressure about 33-35psi. Over 35psi, grip tends to fall off quite a bit.

If I'm trying to set a fast lap early in the session, I'll go out about 30psi, fastest lap usually lap 2 or 3, tires about 32-33psi at that point, stay out a couple more laps and come in.

This is all with 200 treadwear tires. SC3's, Vitour P1's, RE71RS's & RE71RZ's all seemed to like about the same pressures.

[AZIROC]

With my sc3s, usually ill start off in the 26-28 range but try and not go above 33.


Edit: I should have better said i dont try to go above 33. While racibg, usually my dash has the tire pressure up, this way I know that if in getting up to or past 35, Im really using those tires (good or bad) and reevaluate if im driving well or just asking alot" from the tires due ti mistakes im making.

[Msquared]

I'm targeting a bit lower with my SC3s: 32 front and 31 rear hot. I check pressures as soon as I park after a session and bleed down if they are any higher than that. For a ZL1 I might shoot for 33psi hot due to the extra mass of the supercharger on the front.

[ItalianZL1]

Thanks for the inputs guys, much appreciated!

[redfish86]

I got an interesting tire pressure lesson when I soloed at a particular track the first time. My right sides were 1 PSI off from where they had been consistently running after that session. My instructor came by to see how it went and I mentioned the right sides. He told me it’s because his 200# wasn’t riding over there. I made the adjustment, and sure enough, he was right.

I’m running 19” wheels on my car. I’ve run the stock SC3’s, CRS V-2, SC3r, and a set of Trofeo Tracks. For the SC3, SC3r, and the Nankangs, I’m usually starting the morning around 26, and shoot for 32-33 hot, making adjustments accordingly. The Pirellis liked to start a bit higher. I’ve really only run one day with them so I’m still figuring it out on those.

Edit: SS 1LE

[2004YZFR1]

The factory high performance supplement says to start at 28 psi cold all around for the SS 1LE and stock Goodyear Super car tires. But I’m not sure if the ZL1 would be different.

[NG329]

Honestly depends on how fast you are.

On DOT tires, I usually start at 24-25psi and come in at 33-34psi (200TW) after the first session, then I bleed them down to 31psi while they're still hot. After that, they're good for the rest of the day.

With slicks, same cold pressures and sometimes after the first session I come in and they're 37-38psi (Pirelli & Hoosier). Same deal. Bleed them down to 31psi and they're fine afterwards.

At my pace, I get movement at 33-34psi and I don't like a loose driving car. Some guys do and they're okay at those pressures. I find that 31psi hot is the sweet spot for max mid-corner and braking grip on pavement up near me.

Since you're instructing and you probably won't be killing it, I would say 33-34psi should be your target for longevity.

[N Camarolina]

It's interesting. We've had these tire pressure conversations before, and I recall the previous hot targets that most track rats were going for on SC3 was around 35-36 (noting of course that the HP manual suggests 38-39). I'm still targeting that because I find at pressures below 34, the sidewalls tend to roll over a bit more, and the sidewall starts to wear. So I'll start at around 29-30 and probably let a pound or two out as needed during the first two sessions, and maybe another pound preemptively for the first afternoon session since ambient temps keep rising. I usually manage to get 15+ track days out of my SC3s taking this approach.

In this thread, it sounds like most of you are seeking lower pressures. Any idea why the shift?

[Msquared]

Originally Posted by N Camarolina

It's interesting. We've had these tire pressure conversations before, and I recall the previous hot targets that most track rats were going for on SC3 was around 35-36 (noting of course that the HP manual suggests 38-39). I'm still targeting that because I find at pressures below 34, the sidewalls tend to roll over a bit more, and the sidewall starts to wear. So I'll start at around 29-30 and probably let a pound or two out as needed during the first two sessions, and maybe another pound preemptively for the first afternoon session since ambient temps keep rising. I usually manage to get 15+ track days out of my SC3s taking this approach.

In this thread, it sounds like most of you are seeking lower pressures. Any idea why the shift?

I think the SC3s provide more grip and a more gradual fall off the slip angle cliff at lower pressures. Most of us are probably running more negative camber than the manual suggests, too. The two are related.

[Patriot Motorsports USA]

Originally Posted by N Camarolina

It's interesting. We've had these tire pressure conversations before, and I recall the previous hot targets that most track rats were going for on SC3 was around 35-36 (noting of course that the HP manual suggests 38-39). I'm still targeting that because I find at pressures below 34, the sidewalls tend to roll over a bit more, and the sidewall starts to wear. So I'll start at around 29-30 and probably let a pound or two out as needed during the first two sessions, and maybe another pound preemptively for the first afternoon session since ambient temps keep rising. I usually manage to get 15+ track days out of my SC3s taking this approach.

In this thread, it sounds like most of you are seeking lower pressures. Any idea why the shift?

When it comes to tires, the Attorneys are making the suggestions based upon load ratings of the tires.

When it comes to actually putting heat into the tires, you will want to start at 26-28psi and when the tires reach 31psi the grip comes in fast! At 32-35 you are hooked and anything North of that the car will begin to fall off of performance, lap times will suffer. Having the alignment will be critical to keep the life of the tire in check.

[N Camarolina]

Originally Posted by Patriot Motorsports USA

When it comes to tires, the Attorneys are making the suggestions based upon load ratings of the tires.

When it comes to actually putting heat into the tires, you will want to start at 26-28psi and when the tires reach 31psi the grip comes in fast! At 32-35 you are hooked and anything North of that the car will begin to fall off of performance, lap times will suffer. Having the alignment will be critical to keep the life of the tire in check.

OK. Thanks to you and Msquared for the info about the 35psi cut-off and the mention of camber. I'm running -2.2 in the front and -1.5 in the rear. What camber are you guys running with these lower pressures?

[Msquared]

Originally Posted by N Camarolina

OK. Thanks to you and Msquared for the info about the 35psi cut-off and the mention of camber. I'm running -2.2 in the front and -1.5 in the rear. What camber are you guys running with these lower pressures?

I'm not a good gauge for alignment with SC3s because my car is aligned for autocross use with different tires that like more camber. I am running "all of it" front and rear: -2.7 front and -2.0 rear. In back, the limitation is due to the toe settings: any more camber and you can't avoid toe out, which is not good in the rear. These settings do result in inside shoulder wear for the SC3s, which seem designed for less camber. This much may still be fastest, though; and my inside wear could be mostly from me driving to out-of-town tracks on these tires. I'm really not sure.