Colder track days

[sk8erord]

So the first HPDE event at my local track will be in March. Temps in March are still fairly cold - lows in the 30s and highs in the mid 50s. What do you do about tires when the temps are that cold? I don't think I really want to track on my snow tires, but won't that cold prevent my summers from getting up to temp? Couldn't that cold even potentially damage them (as it'll be really cold for the first session or two)? I've heard of tire warmers, but I assume that's more than a HDPE type person would want to invest in...

Thoughts?

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[Trackaholic]

I would not track on snow tires, unless there was actually snow on the track, and would rather drive on the summer tires.

The summer tires will not like the 30 degree temps, but should probably survive as long as you warm them up slowly. I drove on my Michelin Pilot Super Sports in ~27 degree weather (not really trying to do that, it just happened), and they held up fine.

I would take the first lap slowly, going maybe 50% in the corners and under acceleration, but using 70% braking to build heat. Then I'd start ramping up slowly from there.

I think the tread blocks on the winter tires will be too small, and coupled with all the sipes will make the tires chunk under high loads.

But this is all conjecture.

-T

 

[John S.]

I auto crossed the stock pZeros in 45 degree weather and they were completely useless. They would lose traction at the slightest throttle input. No way would I put my car on a track with pirellis in that cold of temps. I couldn't believe how poorly they gripped. I ran 4 times and never once got a clean run where I didn't almost spin out and that was lugging the car in 3rd gear low rpms.

 

[Nine]

I asked a similar question recently and got some good answers. Some of it was related to wet conditions too, but summer tires should be fine in the cold once they warm up.

http://www.mustang6g.com/forums/showthread.php?t=42375

 

[Budwise]

The track will warm up after a few sessions and just go easy on the tires for the first lap to let them warm up. You'll be fine.

 

[Norm Peterson]

I auto crossed the stock pZeros in 45 degree weather and they were completely useless. They would lose traction at the slightest throttle input. No way would I put my car on a track with pirellis in that cold of temps. I couldn't believe how poorly they gripped. I ran 4 times and never once got a clean run where I didn't almost spin out and that was lugging the car in 3rd gear low rpms.

Autocross is not a good indicator of tire temperatures that can be reached during a 20 minute track session. There just isn't enough time, and the carcass flexing that builds heat does not happen nearly as many times.

I've run in low-40° temperatures on Michelin PSS tires, and gave them an easy out lap and gradually picked up the pace over the next lap or so after that before really pushing them.

Noteworthy (particularly if you have track pads and street tires), you may discover that braking that's too hard too soon will unexpectedly activate the ABS, and that the tires that were involved may be noticeably lazy about regaining speed when either the ABS kills pressure to those calipers or you ease off the brake pedal a bit like you might normally do. Pay attention to this.


Norm

 

[grue]

Noteworthy (particularly if you have track pads and street tires), you may discover that braking that's too hard too soon will unexpectedly activate the ABS, and that the tires that were involved may be noticeably lazy about regaining speed when either the ABS kills pressure to those calipers or you ease off the brake pedal a bit like you might normally do. Pay attention to this.


Norm

Norm, sorry to be 'thick' but what do you mean by noticeably lazy about regaining speed...

 

[Norm Peterson]

Say you're going 85 mph and while you're braking the vehicle down to 55 for a corner one or more wheels partially lock and slow down to, say, 40 mph before either the ABS or you take action. Now any 40 mph wheel is still going slower than the road speed and needs to be sped up via friction at the contact patch. But if they're still cold enough they won't do this instantly because there won't be enough grip, for that, and you'll feel them still sliding a little as they get dragged up to speed. You won't have ABS pulsing going on and you may have almost completely gotten off the brake pedal before the sliding stops. It's probably a fraction-of-a-second thing.


Norm

 

[grue]

thanks! i never considered that aspect of braking/abs etc... at the individual wheel speed/friction level.

 

[DickR]

I've run in low-40° temperatures on Michelin PSS tires, and gave them an easy out lap and gradually picked up the pace over the next lap or so after that before really pushing them.


Norm

Norm - Just to be clear are you saying that you drove laps on track in MINUS

40 degree F conditions on Michelin PSS tires? That is 40 degrees below zero F?

Thanks,

 

[Norm Peterson]

No, not (minus) 40. Low (hyphen) 40.


I used to do enough technical writing to get some familiarity with hyphenating a compound adjective ("low" and "40°") when it modifies the noun (temperatures). Yes, it's picky (grammatically correct), and no it's not something easily unlearned.


Norm

 

[DickR]

Thanks Norm. That's what I thought, especially in the context of race track laps, but wanted to be sure.

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