ProCoach

As a driver and an engineer, you want to “normalize” the tire as soon as you can after leaving the pits.

This means reaching the nominal air pressure, internal and carcass temperature and lastly, tread temperature values ASAP.

Spinning the tires is not the primary task, but in GT cars and prototypes, it does accelerate the process slightly.

The total goal is to generate INTERNAL temperature of the tire to propagate heat throughout, normalize as much of the mass of the Tire as possible and to bring up internal pressure closer to what the optimum measure should be.

There will always be a differential between the warmup rate of the fronts to the rears and generally the driver is more in control warming up the fronts. This can be aggressive turn-ins on and in the middle of every corner, but mostly it’s throttle-brake application. Aggressive application.

What this fore-aft conditioning does is generate friction between the belts in the carcass of the Tire, quickly and effectively generating heat, thereby pressure.

Its not just spinning your wheels leaving the pits.

Matt Romanowski

If people want to learn this through practice, it's not too hard if you have a friend to help. Go out and do 2 laps, come in and take temps and pressures. Do another two laps, take temps and pressures. Rinse and repeat. For most people and tires, it will be 4-6 laps for the temps and pressures to stabilize. For people that drive easier and come up to speed slower, it will be 8-10.

Tire construction also plays a large roll in how long the tire takes to come in. Different belt materials (metal versus kevlar or other aramid fabrics), number of belts, and even rubber compounds will change how the tires come in.

Having IR tire temps and TPMS makes it an easy exercise. The screen shot below shows how the temps come up over a number of laps. There are also some neat metrics you can develop with this sort of data as well.

ProCoach

Good Lord! If it took me 4-6 laps for temps and pressures to stabilize, I'd be half a lap back plus at the end of the first two laps of all of the events that I do! Hahahaha!

8 to 10? Most DE groups don't even get a chance to accumulate that number of laps in a WHOLE SESSION on a longer track... Besides, that would mean that the tire NEVER GETS to the target temperature, hence doesn't "heat cycle" on schedule.

At least you're getting your rears up closer to target temp later in the graph! Fronts? Not so much, from what I can see.

Different belt materials and constructions are designed to encourage (and resist) heat propagation and dissipation away from the tread surface. Those that can't, chunk...

But there is VERY little difference in the same driver practicing effective techniques in aggressively bringing the tire tread, carcass temps and pressures up to optimum over the course of ONE or at most, TWO laps from pit lane exit. The difference is in the driver's confidence in and consistency of breakaway characteristics when sub-optimal temps and pressures are present.

When doing tire testing at Michelin's Laurens Proving Grounds, if I didn't get the tire up to target temp in one two-mile OUT lap on their High Speed Handling course, I was excused and replaced with a friend of mine who worked for Michelin and won One Lap of America several times. Our target temps were between 210-240 degrees F on a 2000 lb production car on R-comps.

While I agree the IR tire temps and TPMS sensors are helpful (I use them frequently on LMP cars with gentlemen drivers), this is NOT what is holding most people back from coming up to speed. quickly on "cold tires."

Matt Romanowski

Data?

I've studied this over years and have a different experience. I've seen the same from different tire manufacturers, engineers, and other resources across series from club drivers to NASCAR to DTM. Same data from tire engineers at major manufactures and the people that run the testing. But I guess we've had different experiences.

Driver feedback that the tires are "in" usually starts the 2nd or third lap, but the data shows the tires have not stabilized at that point.

As usual, it's best for people to investigate on their own. It only takes one session and they'll know for their tire, car, and driving. YMMV.

ProCoach

That’s not what you said before. You said “4 to 6,” then “8-10.” My experience is that the goal is UP to speed on the second lap (first hot lap). How do you think qualy laps happen? On R7’s, no less?

My experience is that all drivers, executing fundamental skills with controlled aggression and balanced against available grip (not always on the right side of that grip) come up to speed FAST.

One of the number one things I work with drivers at all levels is to drive in such a way the process of normalizing the tire temps and pressures gets there quicker, WITHOUT losing the car. Since the driver loses the car, not the IR or TPMS sensors , it’s rhe driver’s butt that makes it work and must be developed.

On your second point, most drivers are so inconsistent (improving at a great rate, hopefully) that it’s not the same for everyone and it doesn’t “just happen” on a consistent basis. You have to have a clear plan and practice to make this work in the optimal way.

Matt Romanowski

If you consider that tires work in a range of temperatures and pressures and the build up to and drop off from the optimum ranges is not linear, you would see that my statements are not different While someone might feel the tires are "in" they are still not at the optimum operating temp or pressure. That is why you can do your best lap on the second or third lap (which really is dependent at track length, configuration, and driver) while the tires are not all the way in.

The whole industry around tire heating blankets, trams, and other heating methods is based upon limiting the time it takes the pressures and temps to normalize. Again, YMMV.

ProCoach

While it's not linear (the trend line to optimum and stable temps and pressures), 85-90% of it can occur in a very short period of time, depending on how well the driver adapts to the improving level of grip as the tire temps and pressures reach nominal values.

My experience that top line drivers in Grand-Am, IMSA, formula car, sports racing and other series can achieve statistically similar values in a very short time. And this should always be the goal.

Last time I checked, the fastest lap for most IS the datum that we all want to replicate. Your temps and pressures may not be where they are for an endurance race lap, but they're more than satisfactory to register the best performance from the driver!

gman3280

There is 198 pages to look through and I searched with no luck.

I've had my 2010 Cayman S about 6 months now and on track for 6 DE's. I'm coming from an older BMW where I trail braked and generally slid the car all the way around the track. Not drifting but pushing. I'm in the mid 40's at Road A to give you perspective. Now with the Cayman most have said trail braking and rotating the car around corners is not what I want to do. What I find myself doing now is over slowing the car before corner entry. My lap times show it too. I'm around the same times but with an extra 100hp. Many other things to work on but my biggest is over slowing the car. How do you recommend not over slowing at corner entry?

Veloce Raptor

Gosh, I'll trail brake a Cayman! Perhaps not as aggressively as the BMW...but I'll still do it. Makes a real difference...

gman3280

So was I given bad advice or are your car control skills that good?

What about over slowing for corner entry?

Veloce Raptor

Haha! I'll go with inaccurate advice

I believe when you move your brake zone more into the corner, you'll find the car is very stable and you won't need to slow as much or for as long.

IMO people over/exaggerate the differences in various cars on track. Most modern era cars drive very similarly on track, meaning your inputs will be very similar.

bldn10

Re Cayman, if you want to know how fast you can turn in, D.E.s give you that opportunity. Instead of barreling into the corner, braking, downshifting, turning, etc. , all the while trying to gauge your speed, back off on the preceding straight and start by just holding (cruise?) what your normal corner speed is down to the apex. No problem? Next lap speed up a few mph. Repeat until you don't think you can go any faster w/o losing it. Probably a lot faster than you thought. Then adjust your brake point accordingly.

Kevin Fennell

I don't want to start an argument in here, but can one of the PC's weigh in on this?

If you are just coasting then your corner entry is going to be slower then if you are mildly trail braking, so this isn't that accurate?

Sir5n

Sounds good and sane to me.

Veloce Raptor

I'd agree with this but it is a good way to build confidence. I'd start doing this, for example, on a cool down lap, staying off the brakes. Make mental notes you can use the next session