R Compounds vs. Street Tires
03-02-2007, 11:21 AM
#1
R Compounds vs. Street Tires
OK, in an effort not to hijack another thread, I am going to cull some posts from that thread and get a new one started here:
Originally Posted by 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.
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.
Originally Posted by 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.
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.
Originally Posted by 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.
Maybe tomorrow when I get back into the office, if there is any interest.
Originally Posted by 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 . . .
03-02-2007, 11:29 AM
#2
Ok, so after thinking about this a bit, I reasoned out why it seems to me that a good driver feels like they have lots of warning no matter what tires they are using while a novice driver is really helped by having street tires. It really has to do with inching up closer to the limit versus rushing up to the limit. If you rush up to the limit, the amount of time you have between receiving the audible warning and exceeding the limit is much less than if you inch up to the limit. If you inch up to the limit, you get plenty of warning no matter what tire you use. If you rush up to the limit, the extra warning you get from street tires translates into real extra time to warn you that there may be an impending problem. This chart is my best attempt to explain this phenomena (of course, unscientific)
03-02-2007, 11:32 AM
#3
I think thats one of the BEST explanations of street vs R tires I've seen in a long time. Its simple, to the point, and very understandable, that and todd, i think you missed your calling, clearly you are a paint master!
Larry and Todd, would either of you mind if i share this on a few other forums?
Larry and Todd, would either of you mind if i share this on a few other forums?
03-02-2007, 11:33 AM
#4
I don't mind but I really am no expert. Most of my posts here are intended to be "here I am thinking out loud . . . am I right?" rather than "this is the answer and I know it all." So, use with appropriate warning.
Paint is all I have, and it is so simple that it is quick. I banged out that graph in less than 5 minutes . . . really.
Paint is all I have, and it is so simple that it is quick. I banged out that graph in less than 5 minutes . . . really.
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03-02-2007, 12:17 PM
#8
Rennlist
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One point is that while using the audible quality of tires can be another learning technique, don't count on it long-term. You have to be able to feel the tires for the truest idea of what they are doing. There have been plenty of times where I have been surrounded by the cacophany of open-piped cars, and I can't even hear my own motor, no less my tires. Plus, there are also plenty of tires out there, like MPSCs that squeal like pigs, but stick like glue.
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Larry Herman
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Past Flames:
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1974 914/4 2.0 Track Car
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Larry Herman
2016 Ford Transit Connect Titanium LWB
2018 Tesla Model 3 - Electricity can be fun!
Retired Club Racer & National PCA Instructor
Past Flames:
1994 RS America Club Racer
2004 GT3 Track Car
1984 911 Carrera Club Racer
1974 914/4 2.0 Track Car
CLICK HERE to see some of my ancient racing videos.
03-02-2007, 12:24 PM
#9
Instructor
Let's not forget that the superimposed graphs - the street tire give up at a lower (sometimes not that much lower) limit.
That gives those of us that have some seat time, a safer limit to "play" at the limit at a safer speed and with more time to react.
There are *many* benefits to street tires - even for the non-greens.
Deetz.
That gives those of us that have some seat time, a safer limit to "play" at the limit at a safer speed and with more time to react.
There are *many* benefits to street tires - even for the non-greens.
Deetz.
03-02-2007, 12:50 PM
#10
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So, this statement that I posted in the 'Track Car' thread is not really acurate.
I guess I should forget about the sound and focus on the feel, right? You know that is much harder?
"I was able to use the squealing of my tires to gauge the smoothness of my turning. This really turned out to be a good thing. I knew from 4 years of AX that the noise meant I was not smooth and not on the right approach to the apex. Maybe this is another good reason for street tires in the beginning."
I guess I should forget about the sound and focus on the feel, right? You know that is much harder?
"I was able to use the squealing of my tires to gauge the smoothness of my turning. This really turned out to be a good thing. I knew from 4 years of AX that the noise meant I was not smooth and not on the right approach to the apex. Maybe this is another good reason for street tires in the beginning."
03-02-2007, 01:06 PM
#11
Race Car
helpful info here. i am on the steep end of the learning curve of R comps having used them the first time this weekend. seems like the only way to really learn how to drive them is.....to drive them!
03-02-2007, 01:33 PM
#12
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Originally Posted by paradisenb
So, this statement that I posted in the 'Track Car' thread is not really acurate.
I guess I should forget about the sound and focus on the feel, right? You know that is much harder?
I guess I should forget about the sound and focus on the feel, right? You know that is much harder?
For example, one thing for me is braking markers. On occasion, or at a new track I may look for them, but 99% of the time it is pure sight picture...I brake when it looks right. That is a skill developed over years of matching braking performance, brake pedal feel, tire feel and car speed to those reference points and to what my brain tells me is right. Eventually, you no longer have to look for them.
I think that it is the same way with the tires, eventually you really only become interested in feel, but it takes years of using everything in order to develop that ability.
03-02-2007, 02:44 PM
#13
Nordschleife Master
Originally Posted by Larry Herman
I think that it is the same way with the tires, eventually you really only become interested in feel
03-02-2007, 03:22 PM
#14
Rennlist Member
ding! ding! ding! winner!!!
Originally Posted by Larry Herman
No, it's all about using every available tool to learn, and then discarding what is not longer needed. Use the sound and match it to feel until you no longer need to hear it, because you can feel it. When you get to the point of unconscious-competent, there are many things that you may not use anymore.
For example, one thing for me is braking markers. On occasion, or at a new track I may look for them, but 99% of the time it is pure sight picture...I brake when it looks right. That is a skill developed over years of matching braking performance, brake pedal feel, tire feel and car speed to those reference points and to what my brain tells me is right. Eventually, you no longer have to look for them.
I think that it is the same way with the tires, eventually you really only become interested in feel, but it takes years of using everything in order to develop that ability.
For example, one thing for me is braking markers. On occasion, or at a new track I may look for them, but 99% of the time it is pure sight picture...I brake when it looks right. That is a skill developed over years of matching braking performance, brake pedal feel, tire feel and car speed to those reference points and to what my brain tells me is right. Eventually, you no longer have to look for them.
I think that it is the same way with the tires, eventually you really only become interested in feel, but it takes years of using everything in order to develop that ability.
03-02-2007, 04:23 PM
#15
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This is an excellent thread for a newbie like me. Thanks!
Question for you guys: Am I right that it might be easier to feel the tires starting to slip if you are held firmly in your seat? That way you won't have to process how much "seat sliding" you're doing compared to the tires sliding?
Just trying to figure things out and if I'd learn faster with GT3 seats. I've got to justify this to the wife somehow.
Cheers,
Question for you guys: Am I right that it might be easier to feel the tires starting to slip if you are held firmly in your seat? That way you won't have to process how much "seat sliding" you're doing compared to the tires sliding?
Just trying to figure things out and if I'd learn faster with GT3 seats. I've got to justify this to the wife somehow.
Cheers,