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Greasy to me means lacking the grip they should have. Even with smooth inputs, greasy tires either push or oversteer when overheated. Perfect example was the RX-8 I drove at Toledo. The Hankooks get greasy with heat. My last two runs on Sunday (after improving a ton on the first two runs on Sunday) the car oversteer like crazy. It was drifter's paradise. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Once again I think this debate points to two major variables;

-car differences; fwd,rwd and weight
-driver stlye differences

Personally you couldn't pay me to ever use the MX's for autox again, ever

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91 Jetta GLI STS/DSP 111
85 Porsche 944 ASP 11
http://www.blackforestindustries.com

Miles,

While not a direct comparison, you are welcome to take my car for a spin and can drive it hard. I'm using last year's rt-215's as my daily drivers. My car came in at 3154 when weighed off the truck with whatever fluids they had in there at the time it was dropped off at the dealer.

The RT215's are not as forgiving as my RE070's, but with smooth inputs I think they are fine. BUT, that is on tires that are relatively narrow as compared to what you will be running. The RT-615's are suppose to be better tires too.

I currently have my autocross tires back on my car but will have the Azenis on next week. PM me if you want to fling my car around and then extrapolate from there.

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Beauty is in the eye of the beer holder.

Aaron,

GREAT info. Thanks!

FYI glad to hear that you are hooked by R tires. Almost as good as real race tires . . .

I can absolutely understand the appeal of ST tires for many people. However for folks who compete "Nationally" and need to find the absolutely most competitive tire for their car it sure seems like ST tire choice is a LOT more difficult and $$$$ (and more subject to change) than choosing the best R tire. The situation with racing slicks is similar to R tires with just a couple of manufacturers and viable compounds/sizes for most cars and classes.

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Dick Rasmussen

FS 50 2018 Mustang GT

Moving from a Celica/Spyder on R compounds to ST tires and back, there's no comparison. I hope to never, ever, hear the howl of street tires as you push through a turn and piss time away - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Aaron,

Is tire overheating as prevalent with R tires (Kumhos and Hoosiers) as it is with so many ST tires? If so, is it mostly for two driver cars and/or front wheel drive cars?

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Dick Rasmussen

FS 50 2018 Mustang GT

It's prevalent with all cars... even with single driver cars. A lot of the Kumho 710 drivers have 2 sets of tires and switch them between runs! Most are spraying the tires between runs. The new Hoosier A3S05 has the same over-heating issues as the Kumho, but tend need a little heat for grip, where as the Kumho likes to be ice cold. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Aaron,

Speaking of Street tires vs. race tires:

Did you watch the Final round of the Challenge?

I see from the Toledo Pro results that Gary Godula with a C Mod car on slicks beat Andy Hollis with an ST car in the final round. Based on the class results (before Modified indexing) Gary would have had a roughly 5.25 second wait ON EACH SIDE of the course after Andy's green lights. Been there, done that (Kelly says I had a 6 second wait once and still won).

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Dick Rasmussen

FS 50 2018 Mustang GT

Hey Chris,

That is a super generous offer. What I'm most afraid of is that I might actually like, more than I should, the way your car drives. The last thing I need is to get interested in another expensive car!

Maybe I can catch a fun run sometime.

Aaron,

That summary you put up was better than what I get from any car magazine. Maybe you should turn that into an article and publish it!


I appreciate all the feedback. Dick was right when he summarized what I was looking for. I was considering the RT-615s as a "show up and drive" kind of tire. I have no illusions that even uber street tires are as fast as R comps on a good surface.

I suspect that on surfaces like Sanford (and Rockingham when we used to run there), that R tires don't buy you very much. However, at the other sites, I know the R tires are worth more.

My favorite part of autocrossing right now is having good R tires on a surface like Laurinburg. I even liked the surface at Greenville. It was so consistent and predictable, it was very easy to get a feel for the car there quickly. I just don't know if I can get used to the idea of running on street tires.. but as I consider it, I needed to know what to pursue. Sounds like the RT-615s or maybe the 451s.

I didn't realize the 451s were supposed to be on a par with the 615s. Interesting.

Thanks for all the input.

Miles

That was very helpful. Now I know to be ready in case I need to spray down my tires this weekend. My first time running r-comps on my own car will be this weekend. Thanks Aaron.

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2010 Honda Fit Sport
Couple of bicycles

There is a disclaimer to this statement. The Kumho Victoracer (original) V700 does great with heat, even what would be deemed excessive. The Ecsta V700 needed some spraying. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Somebody needs to propose a rule to preclude tire changing and tire spraying between runs . . . that might help with tire life by forcing longer lasting compounds . . . Of course, the ROAD race 710's (same exact tire) don't seem to have this problem . . . I guess autocrossing is actually harder on tires than road racing.

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Dick Rasmussen

FS 50 2018 Mustang GT

Aaron,

You definetely have run more different tires than I have at autox. But I'm very surprised that you rated Kumho MX as the #1 street tire. And the FK451 over the RT-215. Maybe if you are basing this on cost/performance.

But if money is not the issue I'm surprised you rate the BFG KD so low. I'm running the GY-F1-SC that came on my car. With at least half tread they would be fine in wet with no standing water. Later grip is excellent and straight line is good. I've been told by a number of C5 drivers the KD is even better than the SC. And arguably the Mich PS2 is right up there with them. These are all expensive tires that can double as street/track.

After riding with Chris O in his C5 on the FK451 I would consider them for the price. Cheaper than the MX and can double as a rain tire. I have to say the MX impressed me at first but then that quickly wore off.

Graham

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http://www.greywinds.com

I rated the KD low because it's too temperature sensitive. They like heat, but not too much heat. They are terrible when it's cool out (sub 70 degrees ambient temperature) and fall off horribly with too much heat. The compound is too hard for good wet weather traction, even though the pattern suggests they'd be good in the wet. The KD-W is great in the rain, but horrible in the dry. Price really isn't a factor for me, but the KD is outrageously priced. I wasn't impressed with the KD's on Jack's GS as compared to any Azenis or the MX.

The MX is good only if shaved from new. If you grind them down, they chunk and get too many heat cycles, aside from the lack of grip from a lot of tread squirm. When shaved, they are awesome. Problem is, you need to dedicate them to just autocross, for they heat cycle out with running them on the street. The Azenis can handle a lot more heat cyles than the MX. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

I can remember back 2 years ago when everyone had covers on their tires to try to keep them hot. Now everyone has sprayers. The change in the ProSolo format from 2 runs / 2 runs to all 4 at a time has hurt those that run tires that need to be sprayed. You can scrub the tires or spray in the staging lanes. You can do shock adjustments or air pressure adjustments though.

Rumor has it that PS will go back to the 2+2 format next year. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S