# Autocross. Lets talk Race slicks vs DOT R compounds



## Chickenman35 (Jul 28, 2006)

There you go. A nice place to discuss the technical details of true slicks vs DOT R compound radials for people about to step up to SCCA Prepared or Mod classes. I'll weigh in later, but in my experiences ( 35+ years..yes I'm an old fart :laugh: ) ) , even the very latest DOT R compound tires can not hold a candle to the shear grip and instant transient response of true Autocross slicks. 

This would also be a good place to make recommendations on where to buy tires, what tires to buy, tire pressures etc for the proper care and tuning of all manner of competition tires. This thread is for cornering tires only. With respect, for Drag Racing please start another thread.

Let the discussions begin and please keep it technical and civil. :beer:


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## Chickenman35 (Jul 28, 2006)

BTW...I posted this thread here on purpose. This is where most of the hard core Autocrossers and Road Racers hang out. Don't want it to get buried in the maze of " should I run 19's or 20's " in the tire and suspension forum. Nothing wrong with that...but I think this is the more appropriate forum for this discussion. :wave:


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## Marcus_Aurelius (Mar 1, 2012)

Great idea Richard! With all the questions about race tires lately, this would be a good place to condense everything about tires and wheels for TT track duties. I'll make two separate posts about my view on radial r-compound (touching briefly on non-DOT radial slicks) , and bias-ply race slicks (also known as cross ply). :thumbup::thumbup:


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## TheDeckMan (Sep 26, 2004)

I have found Nitto NT-01's to be the best @ 38psi hot.


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## taverncustoms (Feb 18, 2011)

simple question, who has more grip bias-ply or radial?


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## Chickenman35 (Jul 28, 2006)

For people that do want to run slicks, here's a tip that can save you some money. You can get EXTREMELY good used slicks from John Berget Tire. *Especially around Speed Weeks at Daytona*. Some of the tires are literally " scrubs ". Qualifying tires as well.

When I was crewing on a GTO Corvette, we often bought used sets off him and used those for test days, Regional events etc. For a big National event or money event, then we would throw on a fresh set of stickers. Why waste brand new rubber if you've just changed classes and have to setup and test the car? Super nice fellow and easy to deal with. 

Inventory changes daily, so what you do is send in a request form with sizing etc and he will get back with what he has.

http://www.jbracingtires.net/

Edit: BTW..I'm rather anal about Grammar ( and a million and one other things ). That's why you'll see that just about every single post of mine is edited. Can't stand typos!! :laugh:


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## Chickenman35 (Jul 28, 2006)

taverncustoms said:


> simple question, who has more grip bias-ply or radial?


Don't get hung up on the Bias ply vs Radial question. There are too many variables in race tire construction to simply put it down to Bias Ply or Radial. 

If the question is: " What is faster? A dedicated racing slick or a DOT R compound tire " ...then you can get a fairly simple and direct answer. And that answer is the dedicated Racing slick just about every time. And isn't the end result to go faster? 

Tire construction, especially modern Race tire construction is extremely complicated. *BTW, Road Racing/Autocross slicks are available in both Bias Ply and " so called Radial " *. I'll answer the so called Radial bit later. Whether or not a racing slick is designed as a Bias Ply or " Radial " depends on it's intended purpose and is decided by the tire manufacturer. In many cases a straight Bias ply slick is chosen to give specific handling characteristics and can be just as fast or faster than a Radial style slick. It all depends on the application.

A term " Radial Tire " is used very loosely in modern technology. A true Radial tire has the main carcass weave at 90 degrees to direction of rotation and then a stabilizing belt around the circumference to hold the tread casing in place. A true Radial tire will fly apart without that circumferential " Radial" belt. It as absolutely necessary to maintain the integrity of the tire. We can go into the History of what Radial tires later if you wish, but it serves little purpose in the outcome of which type of tire is faster. 

Most of your DOT competition tires are actually Bias-Belted tires. The very popular Hoosier DOT tire is a Bias belted tire as stated at the RS Racing site and is well documented. Not a true radial. The main carcass is not at 90 degrees to rotation, but is angled to increase stiffness. You can vary the angle of the carcass weaving and number of layers to alter the stiffness and handling characteristics of the tire. A Bias ply tire can be either belted or not. The angles of the carcass weave will maintain the outer integrity of the tire...to it's intended design limits. The tire manufacturer has the OPTION of adding the outer circumferential belt to tune the characteristics of the tire on a Bias ply tire. Then it becomes a Bias belted tire. This style of construction is often used on very high speed and high down-force tires. EG: F1, Lemans Prototype and IndyCar. 

Regarding Race Slick vs Dot R compound:

There is only one true factor that counts. And that is lap times. *A dedicated Road Racing slick is going to beat any DOT R compound tire tire just about EVERY SINGLE time.* DOT tires are limited by minimum UTAG ratings. Slicks are not. DOT tires have to meet minimum puncture resistance ratings. That adds weight. Slicks do not. DOT tires have to have minimum curbing resistance, which adds weight...slicks do not. It is quite common to see the actual carcass threads through the sidewall of a slick tire. Weight is the enemy of racing tires and every effort to reduce weight is used on a dedicated race slick. Racing slicks are a no compromise tire designed to do only one thing...and that is to maximize lap times. A DOT tire has inherent compromises which limit it's abilities. Mainly in compound choice and weight.


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## Chickenman35 (Jul 28, 2006)

Max has mentioned this before and it stands true in every single scientific study. Field results trump theory every time. Look at the results in the SCCA Solo Nationals in Prepared and Mod classes. Do you see any DOT R compound tires winning classes at a National level? The answer is No. There may be an odd fluke, now and then but Prepared and Mod classes are DOMINATED by dedicated Racing slicks. That is basically the end of that debate. You cannot dispute actual field proven results. 

Until you actually run on a proper set of GUMBALL slicks, you cannot appreciate the absolute shear grip and instant transition response that Slicks deliver. Modern DOT R compound tires are very good. But they still fall short of the performance of a true racing slick. As Stone Cold would say...and that's the bottom line. :laugh:


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## Chickenman35 (Jul 28, 2006)

I'd like to provide some of my general observations about various DOT R compound tires and their characteristics. I'll Edit this later as It's getting late.

1: Hoosier A6 and R6:

2: Kumho V710

3: Kumho V700 Victoracer

4: BFG Rival


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## Chickenman35 (Jul 28, 2006)

Tire pressures in the rain. Raise them or drop them? There are two schools of thought to this...and it is important to note that these recommendations come from *Road Racers running in excess of 100 mph.*

The typical American recommendation is to raise tire pressures in the wet. The idea being that this will open the channels in the tire to void water better and to reduce the contact patch of the tire to reduce aquaplaning. There's some misconceptions here that have to be recognized. 

Increasing tire pressure to open the water channels doesn't work that well on a Radial tire or a Bias Belted tire. The whole purpose of the tread radial belting is to stabilize the tread blocks and prevent their moving. It will work somewhat better with a Bias ply tire as the grooves will spread open and the tire contact patch will crown and thus be reduced. The idea being that a smaller contact patch exerts a higher force to cut through the water. The results though, are somewhat debatable. 

European and drivers from the UK seem to prefer the opposite method. They generally prefer to lower the tire pressures in the wet. The idea behind this is that you must " work " the carcass and get some heat into the carcass and the tread blocks. Running lower pressures also helps with braking. Aquaplaning is less of a concern...it was something that as a Racer you just learned to deal with.

Now this all depends on the type of car, the speeds involved, the track itself and most importantly, whether or not you are running a high down-force car. Down-force changes EVERYTHING. But for your typical Regional or Weekend racer in a " Saloon Type " car or non down-force Formula Ford, Europeans and UK drivers tend to prefer dropping tire pressures in the wet.

Now I live in the Pacific North West. It rains a ton here. Very similar weather to the UK. When I was running road racing GT cars, I found that running lower pressures gave me faster lap times. Braking was particularly improved by running lower pressures. Tire temperature came up faster and maintained temperature better. Aquaplaning did increase though. It was something you just got used to. Many of the Road Racers in the Pacific Northwest go the low pressure route. Drivers from California and Arizona seem to go for the higher pressure setup. The local PNW drivers usually dominated in the wet and would often be doing little " Rain Dances " at big events :laugh:

Now, how does this all relate to Autocross? Well, Autocross is a very short, relatively low speed event. Aquaplaning is " relatively " a non issue depending on course size and surface. IE: Concrete or asphalt. Big airport lots ( particularly asphalt ) can sometimes be a problem for aquaplaning, but each course will have to be accessed on it's own. 

The main issue is getting the tire tread temps up and to get them up there as fast as possible. Lower pressures help with that. It is important to remember that tire temperatures in Autocross are generated differently than in Road Racing. Road Racing relies on carcass temperature ( Carcass flex and brake temperature ) to heat the tread surface from the inside out. Autocrossing works the exact opposite. Tire temperature is generated from the outside in. The courses are too short to generate any meaningful internal carcass heat. Nearly all of the tread temperature is generated by road friction. This situation is exacerbated in the wet.

For Autocross I've always found that dropping tire pressures got the tread surface up to temp quicker and resulted in faster lap times. This is from my own experiences, in my own particular neck of the woods, with my car setups and courses. Your results may vary. Take it for what it worth....it's all just info and opinions. :beer:


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## taverncustoms (Feb 18, 2011)

how do you dismiss this?


LAKEVILLE, IN (May 6, 2011) -- In an effort to offer our valued customers more tire size 
options, Hoosier Tire will be introducing two new R80 and R100 radial slick sizes for racers 
competing in SCCA FP, HP, and GTL classes. *Testing has proven these radial slicks to improve 
every aspect of vehicle dynamics from more grip, better cornering speeds, improved tread wear, 
less rolling resistance and faster lap times. Compared to our bias ply cantilevers, the total width 
of the radial slick is narrower to improve aerodynamics and will offer less “fall off” of lap times.* 
Both tire sizes will be offered in the R80 and R100 compounds for FWD and RWD vehicles. The 
R80 will be used on all four corners for RWD vehicles, while the R100 will be used on the front 
and R80 on the rear of FWD vehicles. Both the R80 and R100 compounds on these two sizes 
meet the new EU aromatic free oil standards. 

http://www.hoosiertire.com/pdfs/radial43542_bull.pdf


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## taverncustoms (Feb 18, 2011)

it just crossed my mind that you may have been talking about the non slick radial R compound tires. cause I was referring to the racing Raidial slick vs the bias-ply slick.


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## Chickenman35 (Jul 28, 2006)

taverncustoms said:


> it just crossed my mind that you may have been talking about the non slick radial R compound tires. cause I was referring to the racing Radial slick vs the bias-ply slick.


I was originally talking about true Race Slicks ( Bias ply or radial ) vs Dot R-compound ( Radial ) *as in the subject line*.

Regardless of construction, a true Race slick will beat a DOT R compound tire nearly every time and I explained some of the technical reasons why. I can't make it any clearer.... :beer:

This was all to aid in tire choice for you guys moving up to FP. You seemed to be of the opinion that, because the DOT R compound tires were Radial, they were superior to non-Radial Racing slicks. *Nothing could be farther from the truth.* 

This thread can be expanded to include all information related to Autocross/Road Race tires.


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## Marcus_Aurelius (Mar 1, 2012)

Chickenman35 said:


> Max has mentioned this before and it stands true in every single scientific study. Field results trump theory every time. Look at the results in the SCCA Solo Nationals in Prepared and Mod classes. Do you see any DOT R compound tires winning classes at a National level? The answer is No. There may be an odd fluke, now and then but Prepared and Mod classes are DOMINATED by dedicated Racing slicks. That is basically the end of that debate. You cannot dispute actual field proven results.
> 
> Until you actually run on a proper set of GUMBALL slicks, you cannot appreciate the absolute shear grip and instant transition response that Slicks deliver. Modern DOT R compound tires are very good. But they still fall short of the performance of a true racing slick. As Stone Cold would say...and that's the bottom line. :laugh:



Richard, I intentionally waited till you posted as someone with actual field experience (decades of it) before I wrote anything about the type of *race* tires and their construction-type based nomenclature (which is deceiving in reality as you pointed out). I knew that if I posted my experiences (also based on more than a decade of using all type of race slicks, "radial" slicks, and DOT approved r-compound), it would spark a useless and pretty pointless back and forth argument because of interpretations of google-search information that are not carefully put in context. Like you, at the track (road race and autocross) I witness and experience in my cars that bias ply slicks are faster overall (by a good margin) than radial belted slicks and r-comps when the tires are operating within their optimal range. I mentioned optimal range because data taken from SCCA nationals a few years ago at HTP slick asphalt and cold temperature on this one September week, is sometimes referenced as a usable ground for comparing r-comp to true slick. Again, I applaud you for taking the time to create this thread and for your elaborate posts, the people in the community that race their TT (and other non-TT racers that just browse for the valuable info that we're known to provide here) will be grateful for your contribution. :beer: 





taverncustoms said:


> how do you dismiss this?
> 
> 
> LAKEVILLE, IN (May 6, 2011) -- In an effort to offer our valued customers more tire size
> ...


I've learned to realize over the years that you are very stubborn (not a bad trait ), and when you put something in your mind you'll look for anything to try to prove it right. I've tried to explain to you in a derailed segment in the 1.8t engine technical, then via PMs, and it seems that nothing we say will make you change your opinion (although you haven't experienced racing on any of the two type discussed, let alone gone from one to the other to feel and measure the difference through lap times). If you're so convinced by what you read and put no value in what the practice have proven year after year (the SCCA National, Tours, Pro-Solo, and road racing are there to prove it, and is the biggest data sample you could ever find), then just run with the slower tires. I know SCCA's classing philosophy can be questionable, but there is a reason bias ply slicks are not allowed until the higher Prepared and Modified classes. 

The PDF you're selectively picking in an attempt to hold on to a flawed opinion (it will remain that until an actual real life data sample like Nationals can prove the contrary) is not put in proper context. Hoosier (who is not the leader in soft slick compound like they are in the r-comp segment) is comparing a new radial offering to *CANTILVER bias ply*. Cantilevers are a compromised form of bias ply slicks that are created to allow Prepared or Modified classes that are limited in the rules by rim size. They allow a large footprint to be possible on a narrow rim width. I've put 9.5" of rubber on the ground with 7" wheels using cantilevers in my EP CRX and Saturn. It works because usually everyone in the class is using them (or taking a weight penalty for wider wheels, which is not advisable in low power/momentum cars in certain classes). However, they're not ideal and comparable race tires with full-width mechanical support will obviously work better. How can you take a comparison between better supported race tires vs cantilever compromise solutions and offer it as evidence of anything? Either you're not fully grasping the nuances, or you're just forcing an opinion that has been refuted by experienced people looking to help you (and years of data from archived SCCA results).

I've been accused of slapping information in people's faces, and trying to show "superiority" when posting (and I now restrain myself from posting much in what used to be a good forum section, and categorically avoid numb-down topics so I don't offend), but this is the kind of stubbornness and refusal to accept logical and verifiable information that calls for a response that will get the point across. Someone just reading here won't realize that prior to this I have personally offered, very nicely, several lengthy explanations as to how and why bias ply slicks are faster, and interpret my tone (although still looking to guide a fellow member and future racer) as being patronizing. They say if you're going to play with rattle snakes, you better learn how they behave - this cannot be farther from the truth than with race cars, you can either learn what works with them or get bitten with disappointing results. :beer:


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## Marcus_Aurelius (Mar 1, 2012)

^^^
What cantilever slicks look like vs conventional full-width supported tires (mounted on a 7" wheel in E-Prepared Saturn) 




































Just so it's not assumed that I'm talking out of thin air, I tested extensively in my XP Evo anything from R-comp to radial slicks, to bias ply because I was semi sponsored by Hankook at some point. The result was that Gooyear and Hoosier bias ply put anything else to shame (Goodyear being faster and preferred although not offering as much compensation for wining trophies).


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## taverncustoms (Feb 18, 2011)

I've looked for what the top running 2013 Scca champs are running and did not find what tire they are using just that they are hooiser. in fact any comparisons I've managed to find always say radial is superior, even F1 uses radial. I'll keep looking though.

so forgive me for being skeptical when your the only one "on the internet" who says bias ply are the best, I'm just trying to figure it out as you know I am new to full prep racing, and I do appreciate your Input. in fact its the only reason I'm even looking into it because you are normally a great source of information. I had orig planed on running radial but I'm am looking for the data to convince me to switch to bias-ply sorry if that's an inconvenience for you to verify your information. but like you said this is the internet.:laugh:

So if you can be less offended by the thought of backing up a statement, I bet this thread would be way shorter. and our conversation would be way different. if i say something I at least have a shred of something to back it up and I'm not looking for the one thing to prove me correct I've been searching for the opposite but no success. 

and yes I am stubborn. not trying to be an ass and I think you know that.


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## Marcus_Aurelius (Mar 1, 2012)

I'm not the only one on the internet saying it, have you read Richard's posts? I think his expertise and experience should at least be considered viable and hold some weight to you... No? Like I did the last time we got into tire discussion, I'll do the leg work, search and find Nationals tire results to help you (because I've been there and know the answer). 

BTW, I know that you know I'm not being a dick towards you, and was just pointing out why my response was formulated the way it was to others around here that seems thin-skinned to approach taken when it comes to a debated technical discussions. I know you're not being ass also and know you're a very skeptical person. But you have to realize that it makes no sense that you're taking information on the internet that doesn't necessarily apply to road racing production cars or autocross, accepting it, but questioning the information from the ones that actually do the type of racing you're building for. Ok, F1 says their testing shows their radial race tires, that are sanctioned BTW, are faster. Are you building and entering the F1 circuit? It's kind of like me taking what I read or know about road racing/autocross and arguing with veterans in rally or dirt racing about what tires work in their field without any actual testing on my part. Not a very logical way of being skeptical if you ask me...


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## taverncustoms (Feb 18, 2011)

Marcus_Aurelius said:


> ^^^
> What cantilever slicks look like vs conventional full-width supported tires (mounted on a 7" wheel in E-Prepared Saturn)
> 
> 
> ...


I have no question as to which tire you prefer or best suits your driving style. I figure you have tried many tires. and believe that you run faster on your chosen tire.


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## taverncustoms (Feb 18, 2011)

why do they not make bias ply in 17" sizes


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## taverncustoms (Feb 18, 2011)

thinking the Scca forum is prob better suited to this discussion. then the TT fourm on VWvortex. we will at least have a larger opinion base.


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## Marcus_Aurelius (Mar 1, 2012)

taverncustoms said:


> why do they not make bias ply in 17" sizes


Because they don't want you to run big sizes.... I'm just kidding!:laugh:

Tire manufacturers makes race tires in sizes that will sell. The racing community is very small and means really nothing to the manufacturers in terms of production and revenue. If they're going to go out of their way to make a race tire, they want their production to be sold out. 17 and 18 are not ideal in terms of weight and wheel/tire height. You'll quickly realize, once you get started, that lowering the center of gravity (with no impact to suspension geometry), as well as reducing rotational and unsprung weight via wheel/tire is very beneficial and always done in the sports of road racing/autocross (whenever the person is serious about what they're doing and the rules permit). So by default, everyone building smartly goes for 16 15 or 13, and that's why the race tire manufacturers don't even bother making them in the big sizes (and in-between size like 14) that the hardcore and returning customers won't buy.


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## Marcus_Aurelius (Mar 1, 2012)

taverncustoms said:


> thinking the Scca forum is prob better suited to this discussion. then the TT fourm on VWvortex. we will at least have a larger opinion base.


You will definitely get a larger OPINION base for sure! However, the misinformation can be quite large as well if you don't know who knows what they're talking about. Usually, aside for some rare exceptions, the people on top that spent thousands of dollars and countless hours of R&D don't share things publicly. "Why would I do all the work and just spill it out to the very guy that's trying to beat me at every national event" type of philosophy going on over there. With that said, if it's just what's faster overall for a Prepared car without looking for specifics, you'll find your answer with plenty of opinions (good and bad).


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## Marcus_Aurelius (Mar 1, 2012)

Here is the data sample I promised to gather for you:

Archived page of SCCA Nationals results for the past 10 years. If this is not convincing enough data for you, I don't know what is. Make sure you look for Prepared classes mostly, but Modified, Cart and Formula SAE classes follow the same principle (use bias slicks or stay home). 


http://www.scca.com/solo/content.cfm?cid=44519


And to break it down so you know what you're looking at, Goodyear and Avon are leaders in the bias slick world. Both of them don't make r-comps, therefore that's completely ruled out and put to rest (their "radials" slicks offering aren't usually the correct sizes/compounds for those classes too, and more often than not slower than conventional slicks in similar size and compound). 


Look at the overwhelming Prepared (and Modified) results from last year for example, the winners are generally on Goodyear or Avon (rest assured the Hoosier guys are on bias ply R35a or R25a depending on weight). 





























The pinnacle of taking turns on 4 wheels, the infamous A-mods are also on bias ply (these things are faster in a turn than a F1 car) 












And the class you and I are are building for:


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## Chickenman35 (Jul 28, 2006)

Tavern.. you keep getting hung up on all this Bias ply vs Radial debate. As I've tried to point out throughout this thread, *Race slicks are available in BOTH Bias ply and Radial*. There are many, other factors in tire design that affect performance more than the Bias Ply or Radial construction. Forget the Bias ply vs Radial line of questioning. You should be asking: Why are real racing slicks faster than DOT R compounds

I wish both of you would get away from the Bias ply vs Radial debate. And as I've repeatedly said, there are reasons why some slicks are Belted ( I'm not going to use the term Radial anymore because it's a falsehood ) and some are not. Weight being a big consideration. The radial belt is simply not needed on some applications. Autocross being one application because of the low speeds involved and low down-force levels. *That's why the majority of winning Autocross race slicks are Bias ply with no Radial belt.* 

All of the CP classes that Max posted are on slicks. You argue that the data doesn't say whether or not they are slicks or DOT R compounds. Those who have run SCCA National events or follow it closely know the answer. They are all on Race Slicks.
In a Prepared or Modified class you have to run Race slicks to be competitive. Running DOT's against Race slicks is like taking a knife to a gun fight. Seriously.

Max and I both mean well...but you need to open your mind a bit. The Internet is full of misinformation, incomplete information and you have to read between the lines. One thing I learned in my first years of racing. Get friendly with the teams that are running faster than you. Then find out what they're running and why. There is NOTHING like first hand information from EXPERIENCED people. 

BTW, Tavern...what's your first name? I find it gets more friendly on a first name basis.


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## taverncustoms (Feb 18, 2011)

Chickenman35 said:


> Tavern.. you keep getting hung up on all this Bias ply vs Radial debate. As I've tried to point out throughout this thread, *Race slicks are available in BOTH Bias ply and Radial*. There are many, other factors in tire design that affect performance more than the Bias Ply or Radial construction. Forget the Bias ply vs Radial line of questioning. You should be asking: Why are real racing slicks faster than DOT R compounds
> 
> I wish both of you would get away from the Bias ply vs Radial debate. And as I've repeatedly said, there are reasons why some slicks are Belted ( I'm not going to use the term Radial anymore because it's a falsehood ) and some are not. Weight being a big consideration. The radial belt is simply not needed on some applications. Autocross being one application because of the low speeds involved and low down-force levels. *That's why the majority of winning Autocross race slicks are Bias ply with no Radial belt.*
> 
> ...


as recently pointed out on the SCCA Fourm I will prob not be running racing slicks for at least a few seasons until I have more auto X racing under my belt. So as interesting as I find the subject I'm going to continue to build my race car and just not care about race slicks, I will probably just find cheep tires i can burn through. 

and with that being said. max: that's the same list I found on my searching but all it lists is tire brand, and the brands have both bias-ply and radial racing slicks. so while yes it shows what brand is making a better tire for your class its not showing the actual tire used. so IDK maybe your seeing something I'm not regardless at this point its a pointless discussion for me. maybe we can have it in a few years.


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## taverncustoms (Feb 18, 2011)

Marcus_Aurelius said:


> Here is the data sample I promised to gather for you:
> 
> Archived page of SCCA Nationals results for the past 10 years. If this is not convincing enough data for you, I don't know what is. Make sure you look for Prepared classes mostly, but Modified, Cart and Formula SAE classes follow the same principle (use bias slicks or stay home).
> 
> ...


according to the avon site they only make cantilever bias ply so idk


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## Chickenman35 (Jul 28, 2006)

taverncustoms said:


> as recently pointed out on the SCCA Fourm I will prob not be running racing slicks for at least a few seasons until I have more auto X racing under my belt. So as interesting as I find the subject I'm going to continue to build my race car and just not care about race slicks, I will probably just find cheep tires i can burn through.
> 
> and with that being said. max: that's the same list I found on my searching but all it lists is tire brand, and the brands have both bias-ply and radial racing slicks. so while yes it shows what brand is making a better tire for your class its not showing the actual tire used. so IDK maybe your seeing something I'm not regardless at this point its a pointless discussion for me. maybe we can have it in a few years.


If you read my post #6 about sourcing " lightly " used Race slicks from John Berget tire you would find out that it is far cheaper to run used Race Slicks in a season, than buying new or even used DOT R compounds. John sells scuffed slicks from around $75 to $100 each ( depending on size and brand ) during and after Speed Weeks. He can sell them so cheap because the Pro Teams literally throw tires away. 

But it is a pointless discussion at this point I guess. As they say, " You can lead a horse to water but you can't make him drink ". If you want to buy more expensive tires than you need to, slower tires than you need to and waste a couple of years on setting up your car on tires that are not going to be Nationally competitive, then go ahead and buy your DOT R compound tires. It's you money and your car. 

If anyone else is moving up to SCCA Prepared or Mod classes I'd be happy to make some recommendations on what tires to use, setups needed, pressures etc.


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## Marcus_Aurelius (Mar 1, 2012)

Chickenman35 said:


> If you read my post #6 about sourcing " lightly " used Race slicks from John Berget tire you would find out that it is far cheaper to run used Race Slicks in a season, than buying new or even used DOT R compounds. John sells scuffed slicks from around $75 to $100 each ( depending on size and brand ) during and after Speed Weeks. He can sell them so cheap because the Pro Teams literally throw tires away.
> 
> But it is a pointless discussion at this point I guess. As they say, " You can lead a horse to water but you can't make him drink ". If you want to buy more expensive tires than you need to, slower tires than you need to and waste a couple of years on setting up your car on tires that are not going to be Nationally competitive, then go ahead and buy your DOT R compound tires. It's you money and your car.
> 
> If anyone else is moving up to SCCA Prepared or Mod classes I'd be happy to make some recommendations on what tires to use, setups needed, pressures etc.


I agree, I feel we've provided enough tools (experience, opinion, data etc) for Tavern to make his choice properly. If he decides to go the wrong, or not-so-smart way about it, that is all him. He seems to become selective when reading something and retain only what he wants to see or hear. For example I clearly stated in the result from Nats that AVON and Goodyear don't make DOT r-compounds in usable size or compound for auto-x, and all these cars are on true slicks... cantilever-designed or not (the Hoosiers can be argued if you're so inclined, but we both know from actual experience at the track that they are mostly Hoosier R25/R35 bias ply since they are the tire/compound of choice for Prepared and Modified if you're gonna stick to Hoosier for some reason). Now we can put this behind us and turn the thread into something more productive instead of just trying to point one stubborn person to the right direction. 

In my next post I will ill start with my opinion on various road racing r-comp, then autocross r-comp, and finally slicks for road racing and solo. :beer:


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## Chickenman35 (Jul 28, 2006)

^ :thumbup: :beer:


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## 26B (Nov 17, 2014)

I know this is an older thread. I hope you don't mind me posting here.

I'm autocrossing in Europe (they call it Slalom here) and have been wondering about the reasons for certain racing tire choices in the US. 

We don't have DOT R compounds in Europe so nobody is running them. Most people here are running Avon, Michelin, Yokohama and Pirelli racing slicks. 
Michelins S5B is for instance quite popular because it is sticky from the get go while the Yokohama A005 soft compound needs to warm up first.
Avon compound options are more complicated but very soft compounds are also available. 

I haven't seen people in the US running Michelin, Yokohama and Pirelli racing tires at Autocross events. Is this because of availability or am I just misinformed?
Also, what Avon compounds are people in the US running (e.g. 2700 lbs car with 200 hp)?


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## Marcus_Aurelius (Mar 1, 2012)

Racing overseas, I always wondered the same thing, until I moved to the US. Autocross here, although similar to slalom overseas or gymkhana, is almost a different sport. As a result, it has it's unique set of dynamics and tire choices aren't exempt. 

The tires you are mentioning are excellent soft tires, but are all considered road-racing/circuit soft tires. The tires autocrossers want or need to compete at a high level here operate at a different temperature window (come on with less heat, and drop off and get greassy easier too). That is the reason these weird soft compounds get developed and are widely adopted by autocrossers here. 

Some classes like prepared and modified here can be considered outliers as they tend to go for soft road racing compounds due to their class allowances favoring such a choice. The reason these classes IMO adopt different tires than what is used overseas is pricing-availability/performance. Hoosier and Goodyear tend to cater to US autocrossers in the road-racing soft tires because of their size availability, lower price, while offering comparable performance. Avon for example is great and used by certain cars, but they can never really become a true autocross tire-war contender in that segment (like Hoosier, and Goodyear) because of their limited size availability. I think Michelin, and Yokohama fall in that category as well, too scarce in sizing/availability, and too expensive to compete with Hoosier and Goodyear while offering similar performance.


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## 26B (Nov 17, 2014)

The slaloms I attend last between 60 seconds and close to 4 minutes per run. And maximum speed is between 110 km/h and 160 km/h. So on average they are longer and faster than US autocrosses. But they are not that substantially different, so I think the reason that there are no Hoosier and Goodyear slicks is also owed to some ignorance (when I tell people that Americans also do slalom-racing they would say: 'What? Slaloms with pick-up trucks?'). 

I'm currently running in a street tire class where semi-slicks are allowed (e.g. Toyo R888, Yokohama A048) and would like to run in a 'slick-class' next season. 

I believe the Hoosier A6/A7 would not overheat in our slaloms, which is why I'm thinking about trying them (also, the Michelins cost about $450 per tire, albeit they definitely do work very well at low temperatures).
Our rules allow for actual race slicks, but I see that, for instance, Hoosier doesn't have any 17" slicks in a soft compound option? http://www.hoosiertire.com/rrtire.htm
Can you give specific Hoosier/Goodyear examples what people are running in the prepared and modified classes (17" rim) - or can you tell where you would look for that information?


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## Chickenman35 (Jul 28, 2006)

Regarding DOT Autocross/Slalom tires.

A6/A7 Hoosiers come in several 17" sizes. 

http://www.tirerack.com/tires/tires.jsp?tireMake=Hoosier&tireModel=A7

Where you live ( ambient temperatures ) is very important as far as DOT race tire choice. Hoosiers are very sensitive to track temperature and track surface type. They work very well with higher ambient temperatures 75-100F or 24-38C and on asphalt. They do not seem to work well in lower ambient temperatures and are subject to very short lifespans on concrete. ABS is a must with Hoosiers as they will flat spot in a blink of an eye, especially on Concrete.

For a tyre that is nearly as fast as the Hoosier but has MUCH better grip in cooler temperatures and will last longer, especially on Concrete, have a look at the Kumho V710. The V710 will work in much cooler temperatures than the Hoosiers, is much less prone to flat spotting and you can run them down to the cords with little drop off in performance. 

Hoosiers used to go " off " with about 50% of their tread life remaining. It can make a season very expensive as you basically have to chuck them to stay competitive. I don't know if they still have that problem ( I haven't used Hoosiers in ages because I live in PNW.. cold here ), perhaps Max can elaborate further.

Hoosiers are also sensitive to " dirty " Pit areas and dirty tracks. They will pickup everything on the way to the grid. It can take 1/2 lap to clean them off. Generally more of a problem on Concrete airstrips than asphalt, but it is something to consider. A tire cleaning crew can be very helpful with Hoosiers. At the USA National level, the top teams wrap their tires in Plastic Shipping Wrap to keep debris off them.... a bit extreme but that's what it takes to win.

Kumho V710's on the other hand don't pick up nearly as much debris and will grip well ( even when cold ) usually by the second corner. 


Summary: 

Kumho V710 = wider range of operation and greater longevity at a slight decrease in over-all grip to Hoosiers

Hoosiers = Maximum grip tire that will deliver National Championships under the right conditions. However, it has a narrower operating window and is more expensive to run over a season


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## Chickenman35 (Jul 28, 2006)

26B. What particular 17" size do you need in a Race Slick?

I know Avon makes both Crossply and Radial slicks in 17". You can get them in soft ( A92 ) and super soft ( A45 ) Hillclimb compound which should be perfect for Slaloms. A lot of USA A-Mod drivers use Avon's in the soft and super soft compounds. In fact the Hillclimb record holder at Knox Mountain ( John Haftner ) prefers the A92's over the softer A45's. The A45's can overheat by the end of a fast Hillclimb. I don't know the prices on Avon though. However, it could be cheaper than having Hoosiers A6/A7's or Kumho V710's shipped over. 

http://www.avonmotorsport.com/motorsport/crossply/17-crossply-slicks

http://www.avonmotorsport.com/motorsport/radial/17-radial-slick

Ultimately, a purpose built Hillclimb/Slalom compound Race Slick tire, such as an Avon, is going to be faster than even the best Hoosier A6/A7.


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## Chickenman35 (Jul 28, 2006)

Here's an older in car video of John Haftner setting a new record at Knox Mountain on Avon Hillclimb tires ( A92 compound I believe) . A 1:41.972. John has sent numerous Hillclimb " celebrities " home with their tails between their legs such as Robbie Unser and George Bowland. Bowland attended the 2007 50th Anniversary race and was just flabbergasted at John's speed. Bowland finished a distant second to John in 2007 ( they're good friends ) 

John has since broken this record..it now stands at an incredible 1.37.065 set in 2007!!! It is doubtful that this record will ever be broken unless someone brings a bespoke formula Hillclimb car from Europe. Johns car is a shortened Tui Super-Vee with massive wings, 750 lbs overall weight and a 350+ HP supercharged 3.0 Liter VW/Porsche engine.

Head movement gives you an idea of G-Forces. And bear in mind that his new record is 4 seconds faster!!  Enjoy:


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## Marcus_Aurelius (Mar 1, 2012)

As usual I'm in agreement with Richard, for your conditions and racing environment, I'd recommend the V710 for a R-comp (if that's the route you decide to go). Although the Hoosier A6 can be up to 1 sec faster on longer courses, they are absolute divas that works on a much narrower temp window, and are not as forgiving on mistakes (pressure, size, camber that aren't ideal, and driving errors). So, to take full advantage of the A6/A7 you need to have the setup totally dialed, and be aiming at class wins where they can be the last thing to put you over the top. 

I was just chatting with a racing buddy about how good the V710 are overall (price/performance/longevity). I have a pair of 275-17 710's that were originally used as rears for my front-heavy AWD cars -- they were taken out of primary service once they past their grip prime, but called back upon whenever something else corded prematurely on an axle. Well, they have been at it since 08 and I finally killed them recently in street duties mostly because of massive all wheel spin while tuning my new hybrid turbo setup. They never really fell off (like an A6/A7 would), and that's simply amazing. It's too bad the v710 are not in my preferred height in the diameter/width that I run (a bit too tall 17" 295-up), because I would only run them. 

Another r-comp that is very good and can serve as a bridge between the V710 and the A6 is the R1-s. I tried two sets and they provide performance that is in between the A6/A7 and the 710's. I would not advise anyone against them because they're pretty good. However, for longer courses, lower track temp, finite tire budget, nothing beats the 710's overall in the r-comp segment. 

As for full slicks, 17 is not a popular diameter (anything above 16" still isn't considered a true amateur racing diameter). There are slicks however that come in 17" and other larger diameters, the Goodyear G19 radials is the example that comes to mind. However, in all honesty, it doesn't pay to go with true racing slicks if you're going to use 17's and up. The real appeal of the slicks is lighter non-dot carcasses (think 5+ lbs pounds difference per tire), and less camber dependence. Most of that is lost when going with true slick over r-comp in big diameter since they are likely not of the bias-ply construction. :beer:


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## 26B (Nov 17, 2014)

Chickenman35 and Marcus_Aurelius. Thank you for your information.

I have 17"x9" rims and can fit 245/40 R17 - although the Hoosier A7 in that dimension would probably poke.

I think the A92 may be too soft for the weight of a road-car / sports-car. For instance, an Opel Kadett GTE with a curbweight of 1750 lbs and 13"x10" rims would run on the A53 compound. (And they would say that any softer wouldn't work). Heavier cars like Mitsubishi Evo, BMW M1, M3, M4 etc. mostly appear to run on the Avon 379 compound (but this may also due to availability). 
Unfortunately, Avon's compound list is pretty confusing because it supposedly goes from hard to soft and yet some harder types are closer to the soft-end of that list. http://www.avonmotorsport.com/resource-centre/compounds

The Avons are in a similar price range as the Michelins and Yokohama. It would definitely be cheaper to ship any DOT-R tire from the US to Europe. I'm not necessarily budget constrained and don't worry about longevity much (because I only plan to run a few events on slicks next season), but if an American tire is on par with an European tire and costs over 30% less than why choose a European tire.

The asphalt temperature at our events can vary between 5C and 35 C and are at least 90% asphalt. I guess conditions in the North-East of the US could be similar temperature-wise. I wasn't aware of the fact that the Hoosiers need higher asphalt temperatures. Does that mean that autocrossers would not run a A6/A7 below 15 C at national events?
The reason why I found the A7 interesting is because I read on several occasions that the A6 is the fastest DOT-R autocross tire and than I read this post regarding the new A7 as opposed to the A6: http://www.nasaforums.com/viewtopic.php?f=2&t=128454&start=30 


> The small note that I made was just to point out that during our testing, the A7's were run as +30 point "non-DOT approved" tire on a TTC car that is running at 13.3:1 Adjusted, and took down a 5 year old track record in TTB (on a 100 degree day). The point being that the new A7's are extremely capable. There is nothing "biased" or "random" about this. It was just one of the "side" results of our testing that was primarily focused on lap time differences between the models. The R7's and A7's are not "6's" with new compounds. They are a new tire model.


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## 26B (Nov 17, 2014)

Chickenman35, since you live in the PNW can you give some advice regarding rain tires also? (In case I wanted to cover all bases as about 25% of our events are in rainy conditions). For example, does the Hoosier H2O work at lower temperatures?

The V710 is definitely something to think about. Also, because it is available in a 215/40 16 dimension which would produce a gearing advantage (my second gear is too long and first gear too short). (But this would also mean that I needed to get 16" rims and 215 may not provide the grip-level of a 245 tire).


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## Chickenman35 (Jul 28, 2006)

A lot of guys out here run the Toyo R1R at full tread depth as dedicated rain tires. They work incredibly well even in extreme rain. Only thing that out grips them in the wet is a full purpose built " Monsoon " Wet Race tire, but those will be killed as soon as the track drys. And they are $$$$ The Toyo's are very soft and have a high Silica content which enhances grip in the wet while maintaining tread life. They get too greasy in the dry, unless you shave them. V710's are faster in the dry. 

The Toyo R1R's come in some VERY interesting sizes. How about a 245/35-17 that measures only 23.8" tall. These are one of the shortest 245mm wide tires that you will find anywhere. And the 245mm width is conservative. These tires are more like 255+ mm wide. 

$187 USD from Tire Rack and you should be able them direct from Toyo UK or perhaps even Toyo Europe. DOT legal so you can even drive them to the event.

*Toyo Proxes R1R Product Description and Specs*

http://www.tirerack.com/tires/tires.jsp?tireMake=Toyo&tireModel=Proxes+R1R#


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## 26B (Nov 17, 2014)

I usually run the Toyo R888. (We are allowed to drive anything in the street tire class as long as the tire is road legal). It is actually not that bad in the rain (maybe 15% less lateral acceleration than in the dry). It is just prone to hydroplaning at speeds above 120 km/h. So, the R1R would probably perform better in this regard. 

However, I don't think the R1R would stand a chance against the rain tire guys. 
I may be about 3% to 5% slower compared to the guys running on race tires in the dry but I'm about 10% slower compared the same guys running on rain race tires in the rain.

I did try the R1R in the dry once (unshaved) and also noticed that the tires got greasy quickly and started to shred (and are also slower than the R888.)

(The reason why I'm contemplating about all this is because I'm running in a championship where all slalom-classes are lumped together and one gets more points if one is running in a big field and the slick guys often times have a bigger field. So in order to collect more points I sometimes need to run with the race slick guys, since this can still produce more points than a win in a small street tire field. But maybe I should simply try to be less competitive, but then again the last shirt has no pockets...)


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## Chickenman35 (Jul 28, 2006)

If you're only 3% to 5% behind the slick shod cars on your Toyo 888's, then the V710's should put you on equal footing or very close to it. Mind you, A good set of slicks should still come out on top. I'd be looking into Bias Ply slick tires from Avon or Goodyear as a cost effective solution. The radials are a lot more expensive, which is why I suggest Bias Plies. Nothing at all wrong with a good Bias Ply race tire, which we've discussed earlier in this thread.

Regarding rain tires:

I had forgotten that Kumho makes a Wet Weather 710 called the W710. That would be a very good option for the rain. Much cheaper than race wets, unless you can find good used race wets. They are a bit hard to find. Tire Rack used to sell them, but I don't see them listed anymore. Perhaps you can call them direct or use your European sources.

http://www.soloracer.com/kumhow710.html

W710's are a bit limited in sizes, but they do carry a 215/45 x16. A slightly narrower tire in the wet doesn't hurt.

https://www.onlinetires.com/products/vehicle/tires/kumho/215%252F45-16+kumho+ecsta+w710+86v+bw.html

Personally if I was running in a slick class ( which I prefer ) I would be only looking at purpose built slick tires, for Autocross, Hillclimbs or Race Track. Nothing can beat the raw grip of a good set of " Gumballs ". 

For wet tires it gets a bit more complicated. At lower speeds such as Autocross, something like the Toyo R1R, R888, Kumho W710 or Hoosier H2O would be competitive. But at higher speeds such as a race track or Hillclimb you still can't beat the purpose built wet Tires from any of the major Race tire manufacturers. Goodyear, Avon, Michelin and Bridgestone all make very effective wet race tires.

Have you looked into buying lightly used Race Tires in Europe or the UK? 

In the USA we buy heavily discounted race tires from John Berget Tire. He is a used race tire dealer that is located close to Daytona. When Speed Weeks starts in February, he is flooded with a vast assortment of VERY lightly used race tires of various makes. Some scrubs only a have couple of installation laps or qualifying laps. The big teams will run some tires on Installation laps them set them aside for the race. If they don't use those tires during the race, they would rather sell them to a wholesaler like John Berget, than have to transport them. Transport gets too expensive and they don't have the room.

http://www.jbracingtires.net/


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## Chickenman35 (Jul 28, 2006)

26B: Can you tell us a bit more about your car? Model, modifications, weight, HP, where you run etc. Also where are you located? As mentioned. Ambient temperatures play a big part in what tire to choose.


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## 26B (Nov 17, 2014)

The Diagonals available in the 17" range are usually too balloony (and would worsen my gearing). At least this is the case for Avon diagonal tires - I don't know about Goodyear.
So, I would probably have to go with Radials, albeit I don't have much negative camber.

Thanks for the tip with the W710. This would be a good deal, as I would not want to spend too much on a rain tire just for hedging purposes. 

Used tires don't appear to be readily available in our parts. If they are there, they are of the harder types (for track use). 
But this is not surprising because the Michelin 5SB as an example only lasts 50 km. (Which is enough for maybe 15 runs). 
(I think a tire with which needs to be warmed up significantly, would be risky because impatience could total the car as our slaloms are mostly on (narrow) roads).

The slaloms are in Switzerland, France and Austria. 
I have a BRZ which apart from the shocks is mostly stock. In the race slick class I could also install coil-overs but they don't appear to give a huge advantage (camber plates are not allowed, besides nothing beats tires). I run in the 2 liter class mostly against Integra DC2 and Clio RS and my car appears to be most competitive in my class as I can fit the most tire under my wheel wells (the rules just say that the wheels are not allowed to poke  ).

Examples of our slaloms (most cars on these videos are non-street legal cars though, as they are apparently more appealing than our puny road cars):
http://www.youtube.com/watch?v=WXFpF88iEqA
http://www.youtube.com/watch?v=GQsYnerWOwQ
http://www.youtube.com/watch?v=FFCo0Q41ue8
http://www.youtube.com/watch?v=YPzRWdeubZo


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## Marcus_Aurelius (Mar 1, 2012)

I had a feeling that your slaloms were like our Solo2 here in the US. Higher speed solo that are basically road courses broken by a few slowing elements. These conditions will suit the V710 more than the A6/A7 as you can get the Hoosiers to overheat and get greasy on longer/faster courses (you will go through the Hoosiers very fast too). These courses almost call for road racing compounds, and the V710 wider window of operation would be just about the perfect hot tire. 

My experience with wet conditions is that no street tire will be competitive with the racing wets. If you don't have them, you might as well park the car in the wet as you're wasting your time. The W710 is a great wet BTW!


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## tedgram (Jul 2, 2005)

opcorn:


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## Marcus_Aurelius (Mar 1, 2012)

tedgram said:


> opcorn:


Hey Ted! :wave:


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## tedgram (Jul 2, 2005)

Hi Max :laugh:
In information absorbing mode .


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## 26B (Nov 17, 2014)

Thanks Marcus_Aurelius.

We also have a couple of slaloms which are on parking lots and airfields (but they appear to be less video worthy). These slaloms resemble more an American Autocross. (I once worked in the US and took part at an Autocross in Devens MA and this one did not appear to be that different).
After Chickenman35 mentioned that the Hoosiers A6/A7 don't work well at low asphalt temperatures I'm not too excited about them anymore anyway. 

The W710 looks appealing but Tirerack doesn't sell it unfortunately (and sizes are limited too). Since I need a set of additional rims from Tirerack anyway I was thinking about having 4 tires mounted on them. 
Tirerack does sell the Hoosier H2O though. Do you know whether this tire works at low asphalt temperatures? (I read some raving reviews about it but couldn't tell at what ambient temperatures they raced at.)


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## 26B (Nov 17, 2014)

I know I could also have the V710 mounted on those rims, but as far as dry slicks are concerned I'm meanwhile leaning toward an Avon/Michelin option, because all the slalom-winners in cars similar to mine were running on those two tires. Also, I know for sure that these tires definitely do work at low temperatures. One guy had the fastest time at one event in the morning (before the sun was hitting the road) when asphalt temperatures were at 8C (and his tires were definitely cold when he started).
I think I will just have to bite this relatively pricey bullet.


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## Chickenman35 (Jul 28, 2006)

26B said:


> I know I could also have the V710 mounted on those rims, but as far as dry slicks are concerned I'm meanwhile leaning toward an Avon/Michelin option, because all the slalom-winners in cars similar to mine were running on those two tires. Also, I know for sure that these tires definitely do work at low temperatures. One guy had the fastest time at one event in the morning (before the sun was hitting the road) when asphalt temperatures were at 8C (and his tires were definitely cold when he started).
> I think I will just have to bite this relatively pricey bullet.


I think that is the best decision. Based on the videos', most of your competition is racing on slicks and they will still have an advantage over any DOT R-spec tire, including the V710's. You'll just have to settle with winning by a bigger margin :thumbup:

Bias Ply tires ( Diagonals as you call them ) can have VERY stiff sidewalls. Stiffer than radial slicks. It depends on the manufacturer and what vehicle the tires are designed for. Goodyear Bias slicks for GT cars and Saloons have very stiff sidewalls. But if you can't find them in the size you need it's a moot point.

As for rain tires I would be looking for some good used rain tires or have a re-think on the Toyo R1R's . I sent you a link to the shortest size possible, there are larger diameter sizes if you need to strech your gearing. It looks like a lot of your runs are in 2nd and 3rd gears. 

Have you thought about switching to a 16" rim for your rains or even drys. 16 " is a more popular size and the added sidewall height can be an advantage, *especially with rains*. You need some flex there. A taller sidewall tire ( for the same overall diameter ) is less sensitive to camber changes and is generally better under acceleration and under braking. If 16" wheels will clear your barkes, you should consider them for the rains at least.

Tires with lower aspect ratios are generally less forgiving and need optimized camber curves. Something to think about.

I ran my 1986 Hillclimb Camaro on 265/45x16 V710's very successfully ( IE: = Win ) for years while other competitors were running 275/40x17's and 315/35x17's. I had more forward bite out of hairpins, could go deeper under braking with more control ( no ABS ) and turn in to slow corners was quicker than when I tested and ran 315/35x17's. Transitions in fast lineal slaloms was quicker ( with 265's ) as well. The only place that the 315/35x17's were faster than the 265/45x16's was in very high speed corners. There I simply ran out of usable tread width. 

Eventually for Hillclimbs I was going to switch to 275/40 x17's on the front and 315/35x17's on the rear. The smaller front tire enabled quicker turn-ins to the hairpins at Hillclimbs and lineal slaloms. 315's up front made the car too lazy on turn-in and the car would lock tires easily under braking. Poor braking modulation with the 315/35x17" because of the short sidewall and extreme width of the tire. With 2.5 degrees negative camber ( a modest amount on an F-Body Camaro with Mac struts ) only 3/4 of the tire was touching the ground because of the incredibly stiff carcass. On the other hand a taller but skinnier 265/45x16" tire would " flow " into the asphalt under hard braking. Actually increasing the contact patch area in both width and even more so in length. Under hard braking you would end up with a bigger contact patch than the wider 315. Much easier to modulate as well. Same thing exiting slow corners. All in the design of the tire. 

John Ames ( Multi-time National SCCA Autocross Champion ) successfully campaigned and won with an ESP Mustang for years running the 16" tires instead of 17" tires. He had come to the same conclusions with the Mustang which had Mac struts and even worse Camber curves than the Third Gen Camaro's.


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## 26B (Nov 17, 2014)

Thanks Chickenman35.

That's a good point regarding the 16" and I have considered them. The issue here is that while 17"x9" rim inch are easily available - anything wider than 16"x7" appears to be difficult to find (at least for my car). 
I could still go for 16"x7" rims as a rain option but then I may not be able to use these rims for much else. 

At least I know that the R1R should work at lower temperatures (since the R888 does), but I'd be surprised if it would stand a chance against the guys on race rain tires.

PS: I read old fart somewhere and wanted to add: The guy who won most slaloms in the non-street legal road cars (2 liter class) this season is 70 years old: https://www.youtube.com/watch?v=lgYruDqQc-A


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## 26B (Nov 17, 2014)

The season is meanwhile almost over and thought I report back to you what I went with and what my experience was. 
Since the exchange rates changed last winter/spring and shipping costs increased, I ended up buying racing slicks which were readily available in Europe. I went with the Michelin S5B, since most guys were winning slaloms on this tire. (Since is available with a relatively small diameter I was also able to fit all four of them on the back seat, which wouldn't have been an option with the V710.)
In a direct comparison with the Toyo R888 it was almost 5% faster. They are grippy even at relatively cold temperatures. 
The only issue is that they peaked even after just a few runs and they lasted less than 25 runs (of course even at the end, they were still far superior to any street legal tire). (The reason, I know that they must have lost grip, is because initially the rear wouldn't break out at all - even in 1st gear switch-backs. But this changed after the first few runs).


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