KaiB

Yep, it does get granular at times...

LuigiVampa

That at least was my understanding on out laps. Friction of the tires on the track, and internal friction play its part, but my understanding was that this happened slowly as the tires are brought up to speed.

You need to drive hard to bring tires up to temperature and you need tires to be up to temperature to drive hard.

I bought the book you suggested because I do want to understand these issues more completely. Hell, I still have problems figuring out tire pressures on the really cold days at Lime Rock so I know I need help!

Matt Romanowski

This book also has some great tire info in it that is not found anywhere else. I will warn you though, this is not light reading. When it gets into engineering, it dives deep.

http://www.shock-shop.com/Race-Car-E...ngineering.htm

ProCoach

It isn't? <grin> Matt sleeps with this stuff under his pillow!

True, the former.

False, the latter.

Matt Romanowski

Still doesn't do me any good! So much for osmosis learning.

spg993tt

i used them for a while maybe like 2 years ago, they were not permitted in COntinental challenge, but PCA did not prohibit them. they werent too expensive if i recall. and they were kind of nice in that you put them on myabe , i want to recall, it was like an hour before hand, and you'd just let them heat up the tires. you still had to set your tires, all your sets, to what you wanted for ambient starting temps based on a tire test or your knowledge of the car, track, conditions. and then, you heat them up, so you'd go out with some pressure and temps in the tire. i definately felt i could get on it early but that was also a waste because as any pca racer will tell you, that outlap each practice session and during qualifying is so annoying. dudes at the front are scrubbing their tires, and turning 1:19 lap at NJMP into a 4 minute warmup lap, chewing up like 1/5th the run time or maybe 1/2 the run time before the black or red flags start flying.

as i ran the pirellis, i found these less valueable because the pirellis, as good as they are, have some kind oil or coating that has to be scrubbed out. you step on the gas in a high HP car on those pirellis as you clear the blend line into turn 1, you will spin the car. slippery as glass for a turns so it does take those a few moments of scrubbing off the oils or whatever it is that causes that pirelli to be so slick when new.

on the boxster, with the hoosier R6, it was incredible. i always felt the r6 was best condition , fastest in lap 3 or so. with the heaters, it was lap 1.

KaiB

One drives to the limit of adhesion regardless of what that is. It evolves and changes constantly and a sense for it has to be developed.

Not saying it's easy; it is what it is.

LuigiVampa

I think my speaking in generalities is getting me in trouble here. I should preference most of my statement with "this is what I was taught" or "this is what I think". I'm far from an expert.

That being said, of course you can be aggressive with tires to bring them up to temperature but you can't drive hard if the tires are not up to temperature. Not if you want to stay on the track. Coming out of the pits at Sebring if I gave my throttle more than a wiff I was certain I would do a spin. I saw a few others actually do it.

ProCoach

^^THIS^^

There is a balance between "grip and gone" that changes rapidly from leaving the pit lane to full-on hot. If you ask too much, you spin...

The drivers that master that balance, as it changes, have a HUGE advantage.

LuigiVampa, please don't think I'm being critical. I think you did FANTASTIC for your first race weekend and LOVED the post you wrote on what it was like from the driver's seat.

To expand on Kai's post, every winning racer I have worked with has devoted tremendous effort and practice to honing their "butt dyno" and "butt gyro." Ross Bentley calls it "Traction Sensing."

They do this to master and KNOW the rate at which the slip and slide turns into stick, from the first corner to the next corner and subsequent corners, FIRST lap!

The tire company and OEM vehicle dynamics testers are incredible, in that regard.

But you are not a "passenger" waiting for what the car "does" to you on cold tires.

You MAKE the car do what YOU want it to do, KNOWING that the car is NOT going to stick as well, and drive CLOSE to that moving target's limits until the car stabilizes underneath you.

When I did tire testing for Grassroots a long time ago at the Michelin Laurens Proving Grounds, we measured from ambient to 230 degrees tread temp by the end of the third lap (of the two-mile long High Speed Handling Loop). What was even more amazing was all three laps were always within tenths and often within hundredths...

Steve G, thanks for that input. Very good information, as usual!

LuigiVampa

No worries at all - I didn't take it that way.

What I was trying to convey is that I really need to preface many of my statements as questions. While I have been driving at the track for about 8 years (a blink compared to some of you) it is only in the last 3 years that I have become serious and tried to actually learn what goes into driving faster. Accordingly, I love conversations like this because it helps me learn.

ProCoach

Your approach and curiosity is to be applauded! I think it is only now that you can really start putting to use all the great things that are posited.

You do have a great mentor in Spencer but as someone who has similar history (successful shop owner and racer for decades, albeit not in P-cars), I have learned that there are always things outside your own direct experience that, with careful thought and best execution, can really move your performance forward!

While I do believe pro drivers are, in most cases, MUCH more practiced and more confident top-level am drivers, EVERY driver with sufficient and thorough understanding of the dynamics of the task at hand, endless practice and laser-like focus, is capable of "Flowing Brilliance." This generates data that supports "best execution of fundamental skills," which can be taught and assimilated by other drivers as curious as you!

There are many ways to skin a cat (and drive a car close to it's and the driver's limits), and the journey is a lifelong one. Enjoy!

996tnz

Yes, nicely stated Kai. And Peter, your expanded observations above put goosebumps on my arms, with my hair getting ready to stand up on end too. The challenge and reward of predicting, chasing, and shaping that ever-changing grip limit are very much to blame for a motorsport obsession that stretches to putting my 'affordable' dream car on the line at every opportunity.