Bull

Hey Dr. Pain, are we going to see ANY video THIS year???????

Gary R.

What video????

BostonDMD

Thank you....

Most definetly, after you all teach me how to drive AND where to focus the video camera......

BostonDMD

Just get me in would you please?.....

Veloce Raptor

It's a brand of oil.

Larry Herman

To answer your question, it was the tires masking a technique issue.

This topic keeps coming back because there are too many drivers out there who either do not understand, or do not believe this: Sticky tires will mask all sorts of evils, from driving flaws to suspension inadequacies because of the extreme grip that they produce. Here is a really simple way to explain the difference between a street tire and an R tire. Both tires, by definition, will produce a grip total of 10 (10/10ths, get it?). Naturally, the limit of the street tire is lower, because it has less grip. However, in approching that limit, the street tire will build gradually and sneak up to it, whereas an R tire will be more abrupt, and a slick even more so.

As you lean on a street tire, and sideloads increase, you reach the limit like this 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 8.75, 9 ,9.25, 9.4, 9.6, 9.7, 9.8, 9.9, 10 and then you are sliding. When you are sliding, the grip still remains high. With an R tire the limit builds like this 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7 ,8 ,9, 9.5, 10 (damn, I wish I was on my PC & could graph this). When you are sliding, you lose grip just as fast. You can see how the tire reaches the limit much faster, and so requires much greater driver precision. Many lesser experienced drivers who could safely explore the 8-9/10s regions of their street tires will trundle around on Rs at 5-7/10ths, until they go just a little too quickly and spin. Confident that they have "found the limit" they then back it down into their 5-7/10ths comfort zone and are slow. It is having the skill to control that "little bit" that allows the top drivers to exploit the performance of these sticker but harder to drive tires.

They will also allow you to drive a line that is fundmentally flawed, like Mike found out, but still go fairly quickly because of all of the grip. Mike had no problems staying on the edge of the tire, but it masked his incorrect line. When he went back street tires, he literally plowed out of the turns due to the reduced grip. It became obvious that he had to take a later apex, get on the power, unwind the wheel and keep the front tires at their limit, but not over it.

I hope that my examples have made my thoughts on this clearer.

TD in DC

Larry,

correct me if I am wrong, but I think another way to explain the phenomena you discuss is simply to say that street tires are much more communicative, and they communicate at a speed that many drivers find easier to reach.

Rather than using numbers to illustrate your point, couldn't you say that a street tire starts talking more readily as you reach the tire's limit:
hey,
HEY,
LISTEN,
WHAT ARE YOU NUTS,
I AM GONNA LET GO IF YOU DON'T BACK OFF NOW (which the tire might start saying at, oh, 60 mph in a corner).

By contrast, an R-compound tire can be more like a passive aggressive significant other:
Silence,
silence,
silence,
silence,
Hey ********,
OH MAN YOU'VE GONE AND DONE IT NOW (which the tire might start saying at, oh 80 mph in a corner).

If the driver never reaches the limit, the R-compound tire has said nothing to the driver to let him or her know how ham-fisted they are being.

Or, if the driver isn't subtle or attentive, the driver will just sail right past the last minute warning and the driver will wonder what just happened.

Once you get used to the R-compunds, I "think" you could detect ham fisted driving just like you can with street tires. However, it is much, much easier to do so with street tires since they are so eager to let you know what they think, right?

Just thinking out loud here.

Gary R.

I'm with you TD. My "coach" started me off on Hoosiers in a purpose built car(after a bit of Green in my 997S on MPS2's) and I spent 40+ days progressing using them. I was certainly not the fastest in any group until I spent the time getting faster, learning the car, MY limits, and the track. I find the Hoosiers VERY communicative in my semi-light, underpowered SC and the only times I am surprised it is actually not a surprise at all.. I KNOW I did something wrong well before an "event" (I'm extremely fast though LRP Big Bend.. or not). If I had it to do over maybe I would be better for the experience of street rubber but the reality is I seem to hold my own fairly well and the myriad of instructors I have had the pleasure of riding with haven't hammered me too hard yet. That could be coming though!

TD in DC

With respect to Hoosiers, the hardest thing to get used to was finding the limits during braking. You could lock up the tires without making any noise. The first few times I remember thinking to myself "why does it feel like I just accelerated a little"?

Gary R.

Or.. "sheesh, didn't see that patch of ice!" But it's usually combined with.. "wow thats a lot of blue smoke back there!"

Larry Herman

Todd, you're explanation mirrors what I am saying in a different style. I really could have used a few of your graphs. Maybe tomorrow when I get back into the office, if there is any interest.

Crazy Canuck

My instructor was not that nice looking. I can't think of really anyone that is. You may have met the guy I started with ... Polar Silver 993 with a GT2 wing ... NH plates ... with Tikka on them ...

Sean F

Thanks for the explanation Larry.

Gary R.

Great, there goes the Boston video production schedule!!

TD in DC

How's this? I think this is what you are trying to chart. (the chart is unscientific and not to scale yadda yadda). My point about tire noise is that most drivers perceive what the chart reflects in terms of audible tire feedback . . .