Non-DOT Slicks

[savage217]

no thats why you keep it as a dot rule . if you do away with the dot tire rule it will end up costing car owners more money buying the fastest up to date tire . a set of new slicks cost more than a new set of dot tires . so with people now going out and getting a new set of slicks it will cost less in what way ????? a full hoosier slick for my diasio cost twice the money than the R6 i buy for the porsche in the same size . so why would you want to throw out the dot rule ?????

Because people won't do it. Bert already alluded to the fact that nobody that we know of has purchased true slicks for the prepared classes so what makes you think they will do so for SP classes? People are not going to buy a set of slicks every event. If they do then good for them. Who cares?

[962porsche]

next year when i run my porsche 948 in PA i will be running a full slick tires on that car . there is also a real real good chance i will also be using some kind of tire warmers for the tt .

[zchris]

Well I think that there has been a lot of discussion for no real reason. Having run radial slicks for 10 + years I can tell you in the TT format you would be hard pressed to get a slick to temp in 2 laps, short of tire warmers that are easily outlawed. From a standpoint of running a durable and inexpensive(assuming you buy them used) tire, its a great idea on the practice days for track time. But, the Hoosier autocross tire will be the faster tire on TT day easily. So practice on the slick and TT on the Autocross.
Chris

[chaos4NH]

Actually Bert, it is simple and logical. As Dan stated, the class is STREET Prepared and street tires are required. Yes?

Sam, I'd buy into that 100% if there weren't caged cars and other cars without license plates in Street Prepared. The fact is there are non-street legal cars in Street Prepared and we ALL run non-street legal "Not for Highway Use / Competition Use Only" DOT-approved tires. We seem to have already diluted the meaning of STREET in the SP classes to the point it is an over-simplification to say these are street legal cars running street tires.

No slicks for SP. I get it and I yield.

Gotta give you a +1 for that Bert. Hhhhmmmm, ya know there are even a couple of cars in ST that might not be street legal!

[betelgeuse]

Well I think that there has been a lot of discussion for no real reason. Having run radial slicks for 10 + years I can tell you in the TT format you would be hard pressed to get a slick to temp in 2 laps, short of tire warmers that are easily outlawed. From a standpoint of running a durable and inexpensive(assuming you buy them used) tire, its a great idea on the practice days for track time. But, the Hoosier autocross tire will be the faster tire on TT day easily. So practice on the slick and TT on the Autocross.
Chris

If this is true (I don't see any reason why anyone would doubt him) I say let the slicks in. I run the Hoosier r6 and I don't think I get them up to temp in 3 laps. I always think if I had one more lap I'd be faster. Maybe I'll buy some tire warmers for next year .
Isn't the setup on slicks vs dot tires alot different? I think if slicks were allowed in SP it would not alter the outcome of the TT at all. Even if they are allowed next year I'm sticking with the Hoosiers. My .02 cents.

Greg

[962porsche]

when the diasio runs for longer than 5 laps thats when the tires finaly start to get up to temp . setting up your suspension does change from track to track and from slick to dot tire . but at times the set up is not that deferent . if you let in slicks what do you do for the people that are then running an auto-x slick in the tt ? the down side for a tire warmers is the time from staging to pit out . more than ten minutes and the tires are all cooled back down .

[brucesallen]

Well I think that there has been a lot of discussion for no real reason. Having run radial slicks for 10 + years I can tell you in the TT format you would be hard pressed to get a slick to temp in 2 laps, short of tire warmers that are easily outlawed. From a standpoint of running a durable and inexpensive(assuming you buy them used) tire, its a great idea on the practice days for track time. But, the Hoosier autocross tire will be the faster tire on TT day easily. So practice on the slick and TT on the Autocross.
Chris

I dunno. Last event running Hoosier bias ply 45 compound slicks on my Formula Enterprise car my data acquisition showed maximum s and I set a new class record. One secret is running the warm-up lap as fast and hot as possible. I think my tire takes only half a lap when near new.

[zchris]

Bruce, I thought we were talking about radial slicks. You are correct about the bias ply slicks being quick to come to temp. In fact when I used to think I had no chance in hell of winning I would run the bias plies because I could rabbit the start and get a good leed on the radial tired cars. Then hope like hell I could stay out in front for at least 3 or 4 laps. Then the bias plies would overheat and I would get mugged. But for those first 4 laps they are smokin fast. You guys may or may not have noticed that in SCCA , alot of the SS type cars run the A6 tires for the race as they are fast on lap 1 thru to the end.
Chris

[kfoote]

The fastest lap for the Grand-Am Pirelli slicks (radials) is either the first or second hot lap in most cases. In the Pirelli line, they're a pretty hard tire, and take longer to heat up than many of the other Pirelli options.

When I ran regularly with COM, there were people running slicks in prepared, and by my count, 22 of the 41 track records in FP, PA, PB, and PC are cars that I know were running full slicks at the time, and there are a few there that I know bought new tires for each COM event. There are a few that I know were radials in that group as well.

I certainly make sure I use the best tires I had available for the timed run, and in most cases I set those aside for the TT and don't practice on them. Just because no one is doing it now doesn't mean someone won't if the option becomes available.

As for street registerability, my car hasn't been street registered since I bought it. For me to get it street registered, I would have to get air bags, which I have to remove to race in SCCA. The expense to do so is the primary reason I never street registered the car.

The DOT track tires, though not intended or recommended for highway use, are actually legal for highway use as long as they have enough tread on them. Just because they're not recommended for street use doesn't mean it's not legal to do so. the whole point of the DOT approval process is to make it so that the tires are legal to run on public roads.

[chaos4NH]

Thanks Kevin, I appreciate your hands on input.

[naschmitz]

The fastest lap for the Grand-Am Pirelli slicks (radials) is either the first or second hot lap in most cases. In the Pirelli line, they're a pretty hard tire, and take longer to heat up than many of the other Pirelli options.

Hard tires that take longer to heat up are fastest on their first or second lap? That sounds counter intuitive.

I've got a set of Pirelli Grand Am scrubs that I'll data log at NJMP and I'll see if I can validate any of this.

[kfoote]

The fastest lap for the Grand-Am Pirelli slicks (radials) is either the first or second hot lap in most cases. In the Pirelli line, they're a pretty hard tire, and take longer to heat up than many of the other Pirelli options.

Hard tires that take longer to heat up are fastest on their first or second lap? That sounds counter intuitive.

I've got a set of Pirelli Grand Am scrubs that I'll data log at NJMP and I'll see if I can validate any of this.

Pirelli rates the hardness of the compounds on a scale of 1-8, with D1 being the hardest and D8 being the softest. The Grand-Am Pirellis are rated at D2.

The 1-2 laps is when the tires are new. Yes, they do take longer to warm up after they've been heat cycled, but as sticker tires, the golden lap is lap 1 or two. There are a couple of situations (high track temp and/or long lap) where for qualifying runs the drivers have had to take it easy on the out lap so the speed isn't out of them by the end of the first lap.

I'm sure that with the softer Pirelli compounds on a heavy, high horsepower car, you could overheat the tire well before the end of the first timed lap.

[eastcoastbumps]

no thats why you keep it as a dot rule . if you do away with the dot tire rule it will end up costing car owners more money buying the fastest up to date tire . a set of new slicks cost more than a new set of dot tires . so with people now going out and getting a new set of slicks it will cost less in what way ????? a full hoosier slick for my diasio cost twice the money than the R6 i buy for the porsche in the same size . so why would you want to throw out the dot rule ?????

It depends on what you consider the reasoning behind requiring DOT tires in SP and the other ST and SS classes to begin with. If the rule is intended to stop people from buying fast race tires every event then it fails miserably as a rule. You can still go out and buy a new set of fast race tires that are DOT approved for every event and have an advantage over your competitors that don't.

If the rule is intended to keep street cars competing on a street tire, then it still fails as rule, since DOT race tires will not pass any state safety inspection (at least not where I live!) and are not approved for street use. In some competitors eyes the rule is not serving either function, so the rule is useless.

With that understanding, the rule should be either changed or eliminated. Make SS, ST and SP a true street tire class and require tires that are street legal with more than 2/32" of tread. Disallow any tire branded 'Competition Use Only' by its manufacturer or require tires to have a certain UTQG rating. Or go the other way and eliminate the DOT requirement in SS, ST, and SP, since you can purchase a proper race tire that has no business being on the street with a DOT stamp already. The sole purpose of the DOT stamp on race tires is to skirt a street tire rule.

[Mick]

^ very good points!

[zip4zat]

DOT regs for tires require certain construction of the tire for safety purposes, iirc. ie failure protection for road going cars that other kind of tires dont have. I dont think the DOT rating is exactly addressing how sticky a tire is or can be, but rather its construction. Now this is from the top of my head so Im not citing anything here, but im sure something can be dug up.

If this is valid, an argument can be made that less than P cars dont have the safety req's to protect the driver in case of a catestrophic tire failure that DOT tires are less prone of. In this light, the rules as they have been make more sense.