Tire impressions Yoko race slick vs. A6 on C5Z
03-20-2011, 09:43 PM
#1
Race Director
Thread Starter
Tire impressions Yoko race slick vs. A6 on C5Z
I got some used GT3 race series tires and tried them at a practice Sat. Small overall for C5Z but I figured WTH I'll try them.
250x650 r18
280x680 r18
I ran them on some 9.5 x 18 front rims and 10.5 x 18 rears.
The compound was A0058 which I believe is supposed to last a GT3 25 to 50 laps or so, was MUCH harder than A6 & the tire was VERY light weight, probably no steel belts as they are not DOT.
Well the rears had very limited traction as you may have guessed, but the fronts MG it was like the car was on RAILS.
We had a 6 cone high speed slalom and I could slice the car thru it with so much precision I was amazed as were several of the guys that came for rides. Turn in was instantaneous.
The tire is very square shouldered & looked tall to me but OMG what a treat to drive with.
Today I went back to A6s on stock C5Z rims ( 275x40x17 and 335x30x18) and the same slalom (other direction) for a champ event & it was like I had a stock base c5, the precision was all missing.
So WTH, why were these old YOKO (front) slicks so fantastic?
The light weight? Square shoulders? 18" vs 17"?
Pressures were ball park similar around 30 psi.
I want that precision back, it was like a Porsche or Lotus (as far as steering) on the YOKO's.
Comments?
250x650 r18
280x680 r18
I ran them on some 9.5 x 18 front rims and 10.5 x 18 rears.
The compound was A0058 which I believe is supposed to last a GT3 25 to 50 laps or so, was MUCH harder than A6 & the tire was VERY light weight, probably no steel belts as they are not DOT.
Well the rears had very limited traction as you may have guessed, but the fronts MG it was like the car was on RAILS.
We had a 6 cone high speed slalom and I could slice the car thru it with so much precision I was amazed as were several of the guys that came for rides. Turn in was instantaneous.
The tire is very square shouldered & looked tall to me but OMG what a treat to drive with.
Today I went back to A6s on stock C5Z rims ( 275x40x17 and 335x30x18) and the same slalom (other direction) for a champ event & it was like I had a stock base c5, the precision was all missing.
So WTH, why were these old YOKO (front) slicks so fantastic?
The light weight? Square shoulders? 18" vs 17"?
Pressures were ball park similar around 30 psi.
I want that precision back, it was like a Porsche or Lotus (as far as steering) on the YOKO's.
Comments?
Last edited by froggy47; 03-20-2011 at 09:50 PM.
03-21-2011, 12:15 AM
#2
Melting Slicks
The model is A005G and the compound should be to the right of it, perhaps the D2861U. You have either got the 2009 vintage ENV-R1 or the 2010 ENV-R2 that run in the ALMS GT3 Patron Cup cars. I have been running 280/680's ENV-R1's all around myself. They wear like iron and are very tolerant to a lack of camber. I was told hot pressures should be 28-30 psi, so it sounds like you are in the ballpark. The 280/680's are very tall(26.8" dia.) I like the feel of the Yok's as well but they were not as fast as other slicks until I treated them with Track Claw. Your rears may just need some softening up to reduce wheelspin.
03-21-2011, 09:26 AM
#3
Melting Slicks
You probably aren't getting the rear tires warm enough to get them into the working range. With these cars the fronts heat up a lot more quickly and with a slick they are going to need to be hot to work right.
Try lower pressures in the rear to get some more tire deformation and more heat back there.
Try lower pressures in the rear to get some more tire deformation and more heat back there.
03-21-2011, 12:00 PM
#4
Race Director
Thread Starter
You probably aren't getting the rear tires warm enough to get them into the working range. With these cars the fronts heat up a lot more quickly and with a slick they are going to need to be hot to work right.
Try lower pressures in the rear to get some more tire deformation and more heat back there.
Try lower pressures in the rear to get some more tire deformation and more heat back there.
Thanks.
I was mainly posting re: the fronts & how amazing the turn in was (the fronts did get a little warmer but really nothing compared to a6's)
03-21-2011, 12:04 PM
#5
Race Director
Thread Starter
The model is A005G and the compound should be to the right of it, perhaps the D2861U. You have either got the 2009 vintage ENV-R1 or the 2010 ENV-R2 that run in the ALMS GT3 Patron Cup cars. I have been running 280/680's ENV-R1's all around myself. They wear like iron and are very tolerant to a lack of camber. I was told hot pressures should be 28-30 psi, so it sounds like you are in the ballpark. The 280/680's are very tall(26.8" dia.) I like the feel of the Yok's as well but they were not as fast as other slicks until I treated them with Track Claw. Your rears may just need some softening up to reduce wheelspin.
You are probably right, it was dark in the garage when I looked at the markings & they are SMALL. Now they are outside & it's pouring. I only got the one set so unless I find a source for more, I won't spend too much time figuring out how to use the tire, but they are magic on the front, but WHY, what aspect of the tire makes it that good? Maybe the size?
Last edited by froggy47; 03-21-2011 at 12:07 PM.
03-21-2011, 04:42 PM
#6
Tech Contributor
We are unfamiliar with this particular Yoko, but assuming they are a REAL slick (you did mention NOT DOT), then this is not really surprising.
It seems that most of the tire knowledge on this Forum ends with the Hoosier A6 D.O.T radial. That is truly a shame! Very simply stated, real SLICKS are in an entirely different world of grip.
I think the typical path of discovery is something like this:
[1] Basic street tire => [2] High-performance street tire => [3] R-compound, DOT radial => [4] Hoosier R6 or A6. By the time our track star "discovers" the Hoosier, he thinks he has died and gone to heaven, and his mind sort of closes to other posibilities.
We come at this from the opposite perspective - formula cars, where feather-lite slicks are a way of life. So trying to drive on a D.O.T. radial, including the Hoosiers, is a real challege, due to lack of grip.
To your main question, which I believe you have answered for yourself:
Slicks are not "distracted" by road-style considerations, like steel belts, or long wear, or quiet ride, or resistance to road debris. Thus, the manufacturers can concentrate their manufacture around weight, consistancy, and grip. In short, good slicks are made with soft "rubber" (in varying degrees, called compounds), they have large contact patches, they have very stiff sidewalls, and they are ultra-light (for unsprung weight). They typically require less negative camber, and lower inflation pressures than comperable sized DOT or street tires.
Most manufacturers are moving away from bias-belt construction, to radial plys for their slicks. This is not working as well as they first thought, and if one can get a set of bias-belted slicks, in a fairly soft compound - well, then he IS in heaven!
Ed LoPresti
It seems that most of the tire knowledge on this Forum ends with the Hoosier A6 D.O.T radial. That is truly a shame! Very simply stated, real SLICKS are in an entirely different world of grip.
I think the typical path of discovery is something like this:
[1] Basic street tire => [2] High-performance street tire => [3] R-compound, DOT radial => [4] Hoosier R6 or A6. By the time our track star "discovers" the Hoosier, he thinks he has died and gone to heaven, and his mind sort of closes to other posibilities.
We come at this from the opposite perspective - formula cars, where feather-lite slicks are a way of life. So trying to drive on a D.O.T. radial, including the Hoosiers, is a real challege, due to lack of grip.
To your main question, which I believe you have answered for yourself:
Slicks are not "distracted" by road-style considerations, like steel belts, or long wear, or quiet ride, or resistance to road debris. Thus, the manufacturers can concentrate their manufacture around weight, consistancy, and grip. In short, good slicks are made with soft "rubber" (in varying degrees, called compounds), they have large contact patches, they have very stiff sidewalls, and they are ultra-light (for unsprung weight). They typically require less negative camber, and lower inflation pressures than comperable sized DOT or street tires.
Most manufacturers are moving away from bias-belt construction, to radial plys for their slicks. This is not working as well as they first thought, and if one can get a set of bias-belted slicks, in a fairly soft compound - well, then he IS in heaven!
Ed LoPresti
Last edited by RacePro Engineering; 03-21-2011 at 04:59 PM.
03-21-2011, 06:20 PM
#7
Race Director
Thread Starter
We are unfamiliar with this particular Yoko, but assuming they are a REAL slick (you did mention NOT DOT), then this is not really surprising.
It seems that most of the tire knowledge on this Forum ends with the Hoosier A6 D.O.T radial. That is truly a shame! Very simply stated, real SLICKS are in an entirely different world of grip.
I think the typical path of discovery is something like this:
[1] Basic street tire => [2] High-performance street tire => [3] R-compound, DOT radial => [4] Hoosier R6 or A6. By the time our track star "discovers" the Hoosier, he thinks he has died and gone to heaven, and his mind sort of closes to other posibilities.
We come at this from the opposite perspective - formula cars, where feather-lite slicks are a way of life. So trying to drive on a D.O.T. radial, including the Hoosiers, is a real challege, due to lack of grip.
To your main question, which I believe you have answered for yourself:
Slicks are not "distracted" by road-style considerations, like steel belts, or long wear, or quiet ride, or resistance to road debris. Thus, the manufacturers can concentrate their manufacture around weight, consistancy, and grip. In short, good slicks are made with soft "rubber" (in varying degrees, called compounds), they have large contact patches, they have very stiff sidewalls, and they are ultra-light (for unsprung weight). They typically require less negative camber, and lower inflation pressures than comperable sized DOT or street tires.
Most manufacturers are moving away from bias-belt construction, to radial plys for their slicks. This is not working as well as they first thought, and if one can get a set of bias-belted slicks, in a fairly soft compound - well, then he IS in heaven!
Ed LoPresti
It seems that most of the tire knowledge on this Forum ends with the Hoosier A6 D.O.T radial. That is truly a shame! Very simply stated, real SLICKS are in an entirely different world of grip.
I think the typical path of discovery is something like this:
[1] Basic street tire => [2] High-performance street tire => [3] R-compound, DOT radial => [4] Hoosier R6 or A6. By the time our track star "discovers" the Hoosier, he thinks he has died and gone to heaven, and his mind sort of closes to other posibilities.
We come at this from the opposite perspective - formula cars, where feather-lite slicks are a way of life. So trying to drive on a D.O.T. radial, including the Hoosiers, is a real challege, due to lack of grip.
To your main question, which I believe you have answered for yourself:
Slicks are not "distracted" by road-style considerations, like steel belts, or long wear, or quiet ride, or resistance to road debris. Thus, the manufacturers can concentrate their manufacture around weight, consistancy, and grip. In short, good slicks are made with soft "rubber" (in varying degrees, called compounds), they have large contact patches, they have very stiff sidewalls, and they are ultra-light (for unsprung weight). They typically require less negative camber, and lower inflation pressures than comperable sized DOT or street tires.
Most manufacturers are moving away from bias-belt construction, to radial plys for their slicks. This is not working as well as they first thought, and if one can get a set of bias-belted slicks, in a fairly soft compound - well, then he IS in heaven!
Ed LoPresti
I guess then it's the light weight, I will be sure to weigh them when I take them off, I bet 3.5 to 5 lbs lighter than a similar size a6 and I guess stiffer sidewall, I really don't have a way to compare sidewall stiffness.
It's not the compound durometer rating as the YOKO is clearly "harder" than the a6. I do have a durometer & will post that also, later as I get the time.
It was truly a treat to kill that slalom at the practice day & I could literally put the car a few inches off the apex cones without hardly trying.
A real eye opener. If you guys ever get a chance to use real slicks, do it.
Now I'm wondering what a GT3 would drive like on slicks.
03-21-2011, 07:05 PM
#8
Drifting
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After you run on a real slick life just isn't the same on a DOT tire!
I run 280/650-18 square or 280's in the front and 320/650-18 in the rear. The 680's are just too tall and feel different to me.
In the Yoko's A005 they also make a Super Soft compound which may be ideal for Autocross.
In Autocross I don't know if you could ever get a slick up to full temp but start with much lower initial pressures, On road courses I start at about 22 - 23psi cold. Also you might try a decent burnout just before you pull up to the line, that will help the rears. When cold they spin pretty quickly.
03-21-2011, 07:13 PM
#9
Race Director
Thread Starter
After you run on a real slick life just isn't the same on a DOT tire!
I run 280/650-18 square or 280's in the front and 320/650-18 in the rear. The 680's are just too tall and feel different to me.
In the Yoko's A005 they also make a Super Soft compound which may be ideal for Autocross.
In Autocross I don't know if you could ever get a slick up to full temp but start with much lower initial pressures, On road courses I start at about 22 - 23psi cold. Also you might try a decent burnout just before you pull up to the line, that will help the rears. When cold they spin pretty quickly.
03-21-2011, 07:42 PM
#10
Drifting
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03-21-2011, 07:58 PM
#11
Le Mans Master
For most of us here your statement is a gross mischaracterization. Most of us race in classes where we are restricted on tire selection by size and tire construction rules. Almost every driver here who races, with maybe the exception of the GT classed Corvettes, is restricted to a DOT classified tire. In that world the A6 is the current nirvana. Compared to the other tires I have driven the A6 makes me feel like a hero.
03-21-2011, 08:31 PM
#12
Tech Contributor
Hello, Oli,
I meant absolutely no insult by my comments - it is simply an observation.
If I recall correctly, from a recent thread here, the NASA S2 class racers, of which there seem to be several on the Forum, are allowed the use of real slicks, albeit with a substantial weight penalty.
The Forum is full of examples.
Ed LoPresti
I meant absolutely no insult by my comments - it is simply an observation.
If I recall correctly, from a recent thread here, the NASA S2 class racers, of which there seem to be several on the Forum, are allowed the use of real slicks, albeit with a substantial weight penalty.
The Forum is full of examples.
Ed LoPresti
Last edited by RacePro Engineering; 03-21-2011 at 09:17 PM.
03-21-2011, 09:08 PM
#13
Race Director
Thread Starter
The model is A005G and the compound should be to the right of it, perhaps the D2861U. You have either got the 2009 vintage ENV-R1 or the 2010 ENV-R2 that run in the ALMS GT3 Patron Cup cars. I have been running 280/680's ENV-R1's all around myself. They wear like iron and are very tolerant to a lack of camber. I was told hot pressures should be 28-30 psi, so it sounds like you are in the ballpark. The 280/680's are very tall(26.8" dia.) I like the feel of the Yok's as well but they were not as fast as other slicks until I treated them with Track Claw. Your rears may just need some softening up to reduce wheelspin.
The tire has A-005B (thought it was an 8)
and D2940L-1 printed after that.
I know for sure they are off a GT3 that runs in a spec tire series.
03-22-2011, 10:18 AM
#14
Melting Slicks
After you run on a real slick life just isn't the same on a DOT tire!
I run 280/650-18 square or 280's in the front and 320/650-18 in the rear. The 680's are just too tall and feel different to me.
In the Yoko's A005 they also make a Super Soft compound which may be ideal for Autocross.
In Autocross I don't know if you could ever get a slick up to full temp but start with much lower initial pressures, On road courses I start at about 22 - 23psi cold. Also you might try a decent burnout just before you pull up to the line, that will help the rears. When cold they spin pretty quickly.
I ran a 305/680/18 Pirelli slicks on all fours for a TT just rear scrubs from a porsche team, even with jacked up sizes they were 2 sec faster than the Hoosier dots on Millers outer loop. Could believe how much lighter they were mounted up as well. I don't ever want to go back, I can't go back, I won't go back
of course now I am building a new motor with a dry sump 18k
all part of that slippery slope,
03-22-2011, 03:06 PM
#15
Drifting
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I have to provide some humor, even if it is a little sick since we just blew our second motor in three weekends!
03-22-2011, 03:35 PM
#16
Safety Car
Hello, Oli,
I meant absolutely no insult by my comments - it is simply an observation.
If I recall correctly, from a recent thread here, the NASA S2 class racers, of which there seem to be several on the Forum, are allowed the use of real slicks, albeit with a substantial weight penalty.
The Forum is full of examples.
Ed LoPresti
I meant absolutely no insult by my comments - it is simply an observation.
If I recall correctly, from a recent thread here, the NASA S2 class racers, of which there seem to be several on the Forum, are allowed the use of real slicks, albeit with a substantial weight penalty.
The Forum is full of examples.
Ed LoPresti
A couple of weekend ago I won TTA at road atlanta both days and bagged 2 free tires.... $600+ in tires goes a long way to ease the pain of fuel and hotel costs there an back.
Plus, aren't true slicks pretty much done in a few heat cycles vs. an A6 that will be super fast for 5-6 and then fast for the next 5-6 before it begins to fall off?
Just some considerations that we all work around
03-22-2011, 04:19 PM
#17
Race Director
Thread Starter
Just to add to this... most of us racing and running TTs with NASA are weekend warriors w/o any sponsorship of any kind. We run Hoosiers becuase of the contingency.
A couple of weekend ago I won TTA at road atlanta both days and bagged 2 free tires.... $600+ in tires goes a long way to ease the pain of fuel and hotel costs there an back.
Plus, aren't true slicks pretty much done in a few heat cycles vs. an A6 that will be super fast for 5-6 and then fast for the next 5-6 before it begins to fall off?
Just some considerations that we all work around
A couple of weekend ago I won TTA at road atlanta both days and bagged 2 free tires.... $600+ in tires goes a long way to ease the pain of fuel and hotel costs there an back.
Plus, aren't true slicks pretty much done in a few heat cycles vs. an A6 that will be super fast for 5-6 and then fast for the next 5-6 before it begins to fall off?
Just some considerations that we all work around
The ones I tried had some heat cycles on them (not sure how many) and I was impressed per the first post.
My "guess" is they heat cycle about the same as Hoosiers, give or take depending on the (many) compounds they come in.
03-23-2011, 12:55 AM
#18
Tech Contributor
travisnd,
First off, congratulations on a double win in a single weekend! Those are quite rare, so you must be doing something (actually, many things) right.
We, too, are keenly interested in maximizing our racing dollars. After all, it takes a lot of trophies to purchase a loaf of bread and a jug of milk. So contingencies are important, and I'll come back to that in a second.
It is our long-standing belief that successful club racers should have a good understanding of their equipment - both the strengths, and the weaknesses. And just because one's equipment is limited by sanctioning body rules, or by budget, or by other considerations, that does not excuse one from knowing that something better exists.
Time and again on this Forum, stated or implied, the assertion is made that the Hoosier A6 DOT radial is THE tire with the best mechanical grip. Such a statement indicates a lack of knowledge of the broad category of race tires. And even when such an opinion is confronted with facts to the contrary, that naive belief persists. Not to pick on you, but even your question about slicks and heat cycles seems to reflect a prejudice toward the tires you are using. So be it.
Perhaps for the last time: Structured TESTING removes the conjecture and the prejudice. There is absolutely no substitute for intentional time on the track, with varying pieces of equipment, and a stop watch.
Returning to the Hoosier-NASA contingency program for a moment, won't Hoosier "pay" their contingency for a competitor who is running slicks? (It's a rhetorical question!)
I'll sign off now, before I get myself in even more trouble.
Ed
First off, congratulations on a double win in a single weekend! Those are quite rare, so you must be doing something (actually, many things) right.
We, too, are keenly interested in maximizing our racing dollars. After all, it takes a lot of trophies to purchase a loaf of bread and a jug of milk. So contingencies are important, and I'll come back to that in a second.
It is our long-standing belief that successful club racers should have a good understanding of their equipment - both the strengths, and the weaknesses. And just because one's equipment is limited by sanctioning body rules, or by budget, or by other considerations, that does not excuse one from knowing that something better exists.
Time and again on this Forum, stated or implied, the assertion is made that the Hoosier A6 DOT radial is THE tire with the best mechanical grip. Such a statement indicates a lack of knowledge of the broad category of race tires. And even when such an opinion is confronted with facts to the contrary, that naive belief persists. Not to pick on you, but even your question about slicks and heat cycles seems to reflect a prejudice toward the tires you are using. So be it.
Perhaps for the last time: Structured TESTING removes the conjecture and the prejudice. There is absolutely no substitute for intentional time on the track, with varying pieces of equipment, and a stop watch.
Returning to the Hoosier-NASA contingency program for a moment, won't Hoosier "pay" their contingency for a competitor who is running slicks? (It's a rhetorical question!)
I'll sign off now, before I get myself in even more trouble.
Ed
Last edited by RacePro Engineering; 03-23-2011 at 12:58 AM.
03-23-2011, 09:24 AM
#19
Safety Car
Duh... I didn't even think about the fact that Hoosier makes slicks too. Yes, they would pay out slicks.
Is it not accurate that slicks heat cycle away faster than a DOT R?
I'm not sure who ever stated the A6 is the tire with the absolute best mechanical grip.... that's just stupid. It all comes down to how much one can afford to spend on consumables.
With an unlimited budget I'm sure many more would be experimenting with slicks and taking the hp/weight penalty.
However, testing (or lack thereof) plays another big role in all of this. I don't have the resrouces to go test and experiment with completely new setups and get them dialed in etc. As such, forums like this serve as a sort of testing through the shared experiences and information transfer.
Don't be so quick to run off... I appreciate your input and all the info I can get!
Is it not accurate that slicks heat cycle away faster than a DOT R?
I'm not sure who ever stated the A6 is the tire with the absolute best mechanical grip.... that's just stupid. It all comes down to how much one can afford to spend on consumables.
With an unlimited budget I'm sure many more would be experimenting with slicks and taking the hp/weight penalty.
However, testing (or lack thereof) plays another big role in all of this. I don't have the resrouces to go test and experiment with completely new setups and get them dialed in etc. As such, forums like this serve as a sort of testing through the shared experiences and information transfer.
Don't be so quick to run off... I appreciate your input and all the info I can get!
03-23-2011, 09:32 AM
#20
Safety Car
Slicks being 2 sec faster than A6 is anecdotal until someone actually does it. There is quite a bit of evidence to the contrary though. The problem after that lies in the availability of contingency for faster tire, cost/availability of said tire, penalties/allowance for said tire, and amount of testing necessary to extract the extra 2 seconds difference from said tire.
Really all we have to compare to is off the shelf slicks, and no one is out proving them to be faster than the DOT A6's. I think there are some custom slicks out there that are faster, but they are unobtanium.
"that does not excuse one from knowing that something better exists."
:
Really all we have to compare to is off the shelf slicks, and no one is out proving them to be faster than the DOT A6's. I think there are some custom slicks out there that are faster, but they are unobtanium.
"that does not excuse one from knowing that something better exists."
: