Too cold for 200TW
03-20-2024 | 02:35 PM
#16
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From: The Swamps of Jersey/WGI/VIR...
Kind of tough to do that (highly localized heating), especially in cold ambients. That would result in severe graining and tearing to the tire tread face.The tire tread temp overheating can occur on taller, unsupported tread blocks in unshaven 200 TW (or any other treaded tire with more than 4/32nds tread depth, but then it tears or chunks.
Those of us monitoring inside tire temp, pressures as well as the tread surface temps simultaneously rarely see thermal shock in the warmup process on the tread face of the tire and a big temp delta on it’s own. Maybe Matt will chime in on this, since I know he’s got a lot of personal data on this.
If you’re driving quickly enough to get the tread face to the 180-200 degree F operating window, especially with ambient 40 or 50 degrees less than a nice late spring or early fall day (say 75-80 degrees F), you’re not going to be able to do that independently of raising the carcass temps, hence pressures.
When tire engineers work with drivers testing tires (BTDT), they’re far more concerned about the support provided to the carcass by reaching the target range of internal pressures. They say don’t push it when below a pressure threshold, but they say the most efficient and quick way to heat the internal carcass is accel/braking to allow the belts to generate friction, hence heat, thus raising the tire pressures without shock or potentially doing damage striking the curbing, for instance.
I test and race on slicks frequently in the 32-42 degree ambient range (since the temp swings are so wide here in VA/NC, was on track yesterday) and my cold pressure at normal ambients are 14/16 cold on my car. In the 32-42 degree ambient, I start 2 lbs high each end and still are shooting for 20 hot all around. Thats what I did yesterday and it worked perfectly. Never had graining or tearing, either.
In cold ambientes, just go easy, exercise the tires with fore and aft loadings to bring the internal temps and pressures up, then as the grip comes in, go.
Those of us monitoring inside tire temp, pressures as well as the tread surface temps simultaneously rarely see thermal shock in the warmup process on the tread face of the tire and a big temp delta on it’s own. Maybe Matt will chime in on this, since I know he’s got a lot of personal data on this.
If you’re driving quickly enough to get the tread face to the 180-200 degree F operating window, especially with ambient 40 or 50 degrees less than a nice late spring or early fall day (say 75-80 degrees F), you’re not going to be able to do that independently of raising the carcass temps, hence pressures.
When tire engineers work with drivers testing tires (BTDT), they’re far more concerned about the support provided to the carcass by reaching the target range of internal pressures. They say don’t push it when below a pressure threshold, but they say the most efficient and quick way to heat the internal carcass is accel/braking to allow the belts to generate friction, hence heat, thus raising the tire pressures without shock or potentially doing damage striking the curbing, for instance.
I test and race on slicks frequently in the 32-42 degree ambient range (since the temp swings are so wide here in VA/NC, was on track yesterday) and my cold pressure at normal ambients are 14/16 cold on my car. In the 32-42 degree ambient, I start 2 lbs high each end and still are shooting for 20 hot all around. Thats what I did yesterday and it worked perfectly. Never had graining or tearing, either.
In cold ambientes, just go easy, exercise the tires with fore and aft loadings to bring the internal temps and pressures up, then as the grip comes in, go.
03-20-2024 | 02:38 PM
#17
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I'll be there and on R7's as well and that has been my experience...bring them up slow, especially that first session and all should be good. I think it was our first event last year at Summit that it never really got out of the 30's either day so I took 3 laps before I really wailed on the tires and they were solid the rest of the session.
I was just pointing out it's hard to overheat the tread of the tire without it first getting warm internally and by doing that, get up to pressure.
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03-20-2024 | 10:25 PM
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I think Peter's comments are pretty solid. It's really the pressure that supports the tires. When it's cold, I start up a few pounds and just bleed down more often and more air to get to the same hot pressures. The track being cold is the largest cooler of the tires on our cars, so it takes a bit to get heat in them. On my car, I've seen the tire temps not get hot enough for good grip regardless of the amount of driving or warming I did.
Different than Peter - I've blistered tires on a cool day and seen it lots of times on slicks. When I did it (on 200 tw tires before they were a thing) it surprised me. It looked a little different and happened driving at a lower level than I expected it to happen.
Different than Peter - I've blistered tires on a cool day and seen it lots of times on slicks. When I did it (on 200 tw tires before they were a thing) it surprised me. It looked a little different and happened driving at a lower level than I expected it to happen.
03-21-2024 | 09:54 AM
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It's really the pressure that supports the tires.
I've blistered tires on a cool day and seen it lots of times on slicks. When I did it (on 200 tw tires before they were a thing) it surprised me. It looked a little different and happened driving at a lower level than I expected it to happen.
I've blistered tires on a cool day and seen it lots of times on slicks. When I did it (on 200 tw tires before they were a thing) it surprised me. It looked a little different and happened driving at a lower level than I expected it to happen.
A tire’s age can play a big part in blistering or chunking. If it was before 200 TW tires where a thing, that was probably from an era when you, me and a bunch of folks just drove tires, no matter what the age and wear, until we could afford new ones! Folks are a lot more cognizant about date codes and storage care now, don’t you think?
03-21-2024 | 11:41 AM
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RE71-RS need a true heat cycle before hammering on track or Autox. Going out and hammering a Stone, pun intended, cold tire can result in tearing the center tread. We're not in a race at DE so take a couple of laps to build heat and pressure. When it's cold I shoot for ~2 psi rise on the TPMS to tell me they are ready. Also it is very noticeable under braking when they are cold as they will slide/skitter not grip. 100%+++ what ProCoach said brake and accelerate to build heat not this swerving which does little to build heat but has led to loss of control and incidents.
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ProCoach (03-21-2024)
03-21-2024 | 12:28 PM
#22
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I’ll bet you aren’t doing that now with all the good information you log!
A tire’s age can play a big part in blistering or chunking. If it was before 200 TW tires where a thing, that was probably from an era when you, me and a bunch of folks just drove tires, no matter what the age and wear, until we could afford new ones! Folks are a lot more cognizant about date codes and storage care now, don’t you think?
A tire’s age can play a big part in blistering or chunking. If it was before 200 TW tires where a thing, that was probably from an era when you, me and a bunch of folks just drove tires, no matter what the age and wear, until we could afford new ones! Folks are a lot more cognizant about date codes and storage care now, don’t you think?
Sometimes knowing what to do and then actually doing it don't coexist. These tires weren't old, but still did it. It was a wet to drying track with the sun coming out. I slid them probably a little too early.
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gbuff (03-21-2024)
03-21-2024 | 04:01 PM
#23
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Matt Romanowski (03-21-2024)
03-21-2024 | 04:31 PM
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From: The Swamps of Jersey/WGI/VIR...
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ProCoach (03-21-2024)
