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Well there are street tires and then there are the Azenis. I am talking about your "typical" street tire with wear rating of 300 or more. Not the fringe tire. Azenis are as close to a race tire as I think you can get without going to "R" compound tires. I form this opinion based on autocross times I've seen. Very impressive with this tire.

For this tire yes, I agree heat cycling might do something. But for a mud and snow 300 tread wear rated tire, no, nothing worth talking about. And THESE are the tires I suggest for students. If you can drive well using these bricks you will have learned the skills necessary to take full advantage of Azenis or R compound tires.

Agreed. Any top tier performance street tire should be given a good hard run before hitting the track. If you are running what Ron suggests, I doubt that they will be new when you hit the track, but if they are, don't worry about it.

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Rich
http://www.v8mongrel.com/

I would be a bit careful about that statement wrt R-compound tires. The tractive force versus slip angle curve can be dramatically different for R-compound tires versus street tires, particularly over the top of the peak where some r-compounds have very sharp drop offs similar to slicks (i.e. Hoosiers) and all have sharper peaks/drop offs than regular tires. If a student is only used to the nice forgiving response of a street tire, they may be used to driving at too high slip angles (i.e. over the peak of the curve) at times. They have not necessarily developed the skills of using the very top of the force/slip angle curve and staying on the left side of the peak. It's also possible that they won't have the skills necessary to recover from a large slip angle event where they rapidly lose tractive force much faster than a street tire.

I think one of the key skills they need to learn is operating on the left side of the peak at high levels. I've seen many who regularly think they are going faster but in fact are just running at higher slip angles on the right side of the peak and generating the same tractive force (and howling their street tires like crazy). The feeling of the higher slip angle is deceptive. Operating in this region leaves nothing left to recover since if you need more grip, additional slip angle is only going to yield less. Staying just to the left of the peak and generating the same grip yields some reserve in case it is needed…exactly what everyone at an HPDE should be shooting for imo.

Yikes....sorry for rambling on here...

Chuck

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Current stable:
2019 BMW M2 Competition slicktop 6MT
2011 BMW M3 sedan slicktop 6MT
2007 BMW 328i wagon (slushbox for now)
1975 CanAm 125MX2

so with that in mind Chuck, should i consider driving on an r compound in the afternoon sessions provided the temperature is above 50F ?

VIR Full will be my 4th HPDE and my 2nd trip to VIR Full. i have some gently used Kuhmo V700's @ my disposal. i was thinking i would wait untill the weather and the track surfaces were consistantly warmer before experimenting with an r compound.

and of course i would discuss this with my instructor prior to making the switch.

but an experienced opinion would be welcomed. steve

Steve,

my personal opinion would be to stick with the street (non r-compound) tires for a few more events. I would say at least 8-10 full HPDE 2 day events total before running r-compound tires. Like alot of other go-fast goodies, it's hard to go back to regular tires once you take a hit from the sticky tire crack pipe. I ran street tires for at least 12 full HPDE's before trying r-compounds, and I actually wish I had waited even longer- I think I would be a smoother (and likely faster) driver today if I had spent more time on regular tires.

The temptation to keep up with others in your run group is very strong, but if you can resist for a while longer, you will be better off for it.

My 0.02 cents worth.


Bret.

Steve

I'd stay on streets. If you spin on R compound tiers you'll most likely ruin them.

Chuck, you have a valid point. My point is that to turn good times on streets you must be smooth, and easy on them. If you carry that over to Rs then you will benefit. If you start on Rs they will cover bad habits and make it more difficult to continue up and to the right.

R

Steve,

I can only relate my own experience I guess. I started autocrossing in 1975 and did a bunch by 1981 when I did my first track event at Road Atlanta. By the time R-compounds came around in 1985 (Goodyear Gatorback VR-S -- they were actually "S" compound tires at the time as Goodyear made them special for a race series and auto-x, track, etc...The term R-compound was later coined after Yokohama came out with the A-008R, but I digress), I already had a lot of experience I guess, but I had zero issues adapting right away to their higher limits and different response.

Personally, I don't have a great bias against early experience with r-compound tires. Depending on the driver, I think some can adapt very quickly and learn quickly on r-compound tires. It really depends on the learning curve the student is on, the car/suspension and how well it communicates to the driver, and how much knowledge the student has about what is really going on at the contact patch/road interface. However, I can't say enough good things about the usefulness of significant auto-x experience...it would be a great place to learn the characteristics of r-compound tires, especially at some of the airport auto-x events where you can get some reasonable speed corners.

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Current stable:
2019 BMW M2 Competition slicktop 6MT
2011 BMW M3 sedan slicktop 6MT
2007 BMW 328i wagon (slushbox for now)
1975 CanAm 125MX2

one season of autoX and twice @ rockingham with one set of michelins street tires. the car is too much for the michelins, with the tuning that has been done. i have the falken 451's for track this season and the michelins for autoX.

i hesitate to run the Kuhmos in autoX because: 1) i am running in the street tire class. 2) i am more likely to over correct and slide sideways @ autoX 3) my autoX "skills" are not as instinctive as my overall driving abilities.

however, i truly appreciate your comment Ron, one lap or two and bang there goes the r compounds.

but this is my line of thinking. in the downhill esses @ VIR i was hanging out the rear end a bit. i was concerned as i had spun most unexpecedly @ rockingham in a similar manner. while the Falkens performed well (returning some confidence level) i was still apprehensive. i think i would like to experience monster grip once or twice just to use as a guage as to what the car and myself were capable of pulling off. i am sure i will be able to resist the dark side to at least a certain extent. maybe run r's in the TT's next season. anyway, that is where i am at. i would rather sink $$$$ into HP gains than tires at this point. steve

Steve

If the car was sliding around then you are most likely over driving it. Instead of changing tires as kyourself what you were doing to make the car slide and correct that. R compound tires will NOt make you any better but maybe just faster. So when (not necessarily if) you overdrive the car it is going to go off track as higher rate of speed. So now not only do you need new tires, you might also need a new car.

Remember that our school, like all HPDE's is a place to learn techniques not to find the ultimate in speed. Learn the techniques well and the speed will come. Change to grippy tiresto "fix" a problem and the problem is still there just hidden...for a while.


Ron

Steve,

I agree completely with Ron's comments. Stick with street tires and look at how you are influencing the car to get the tail out. I would also look carefully at the car setup itself. If it is stock, are all bushings in excellent condition, is the alignment correct front and rear, are your tire pressures set properly (proper front to rear bias), etc... A complete understanding of all these issues should be second nature to you prior to even considering r-compound experience.

Chuck

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Current stable:
2019 BMW M2 Competition slicktop 6MT
2011 BMW M3 sedan slicktop 6MT
2007 BMW 328i wagon (slushbox for now)
1975 CanAm 125MX2

Ron, let me clarify "hanging out the rearend". i was using the available grip while proceeding thru the esses at an accelerated pace. i did not have a squealing or slipping issue. i was rotating the car i believe.

so apparently my confusion is regarding the amount of grip, or the difference in grip between a r vs. a street tire in this situation. i personally feel i am very conservative on track but will when feeling comfortable attempt to negotiate turns in a more deliberate manner, in hopes of turning a smoother & faster lap. steve

Chuck, i am on Dave's semi regular visit list i believe. i need to tighten the nut behind the wheel way more than anything on the car. steve

If you want to have money to spend on HP then you can't beat the price to performance of the Azenis. I have a set of RT-215's that I bought in June of last year that I'll be using at VIR next week. I've used them at four autocrosses and 6 HPDE's. Autocross put a lot more wear on them than the HPDE's. I also have a set of Toyo RA-1's that I use for the time trials. They are almost gone after the equivalent of 2 HPDE's.

At Rockingham the RA-1's were only about a second faster than the Azenis. I know that's at lot when doing the time trial but not much difference when your out there learning during the HPDE. I've have more than one instructor comment on how well the Azenis performs for a street tire.

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Mitch Moore

so based on the forecast for sat which tires would you guys advise me to use

Azenis rt-215s
or Kumho exta supra 712s

both are about the same tread depth, Kumho sidewalls are super soft but that might not matter in the wet.


other than that, I cant wait!

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traded the ultimate driving machine for a hatchback.....

712s. The compound on the Azenis is not friendly to the cold. And you supposition that sidewall stiffness is not particularly relevant is correct.

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Rich
http://www.v8mongrel.com/