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Discussion Starter #1
So after two track days (150+ miles), I'm convinced that the AD07s are not suitable for heavy track use. Sure, I suspected that going in, but I was hoping . . . .

Here's my first-hand experience with the AD07s:

My first day out, I was limiting myself to 15 minute sessions, it was cool (low/mid 60s) and overcast. The track never heated up and I was only driving 8/10-ish. Taking the fronts up to 31 psi led to adequate turn-in feel with reasonable balance. I figured the tires were adequate after that day (but I can quote myself as saying "With a little more tire than the AD07, this thing will be a giant killer.").

My second day out, I was running 20 minute sessions, it was warmer (mid 70s) and sunny. The track was hot and I was pressing a bit more, in the braking zone especially. I started the day out at 31f/30r cold. After about 5 laps, the front tires started to go away - enough so that I HAD to trail brake to keep the front end planted enough to turn in (i.e., fight the now-persistent understeer). A pass down the pit lane to restage and let the tires cool off didn't do the trick, so I upped the front pressures before the subsequent sessions. I ended up at 35 psi front (42+ hot), with mediocre turn-in and balance, but with just enough pressure to take the heat of the entire session without a pit lane cool-off. I have to amend my conclusion to: the AD07s can't take the heat, and really aren't suited for hard lapping days.

Anyway, now it's time to find an alternative tire for track/road use, and it looks like the A048s are really the best choice, especially since I'd like an all-around tire without having to switch from my stock wheels. I figure that 195/50s will work fine on the stock rim widths (Yoko recommends 5.5-7.0" width rims), and round out the profile of the tire somewhat (good, since we don't have much negative camber). But in this size the A048s are the only thing available.

Since I'm all about choices, I wanted to investigate other options. One choice that comes close are PZeroAsimmetricos in 194/45 -- but the A048 is a superior tire, I think. Any disagreement there?

Going up to 205s, you can get the R3S04 or RA1. The RA1 may be a bit tall (aspect ratio of 55). And the Hoosiers usually run wide, but Randy & Co. report that they fit reasonably well. You could run the Toyos on the street in the dry, and they hold up really well (Miatae folk can get whole seasons out of them, although not necessarily competitively). I've just never really loved the RA1s on my Miata, and would prefer something else. The Hoosiers would require a swap of rims at the track, and I'm looking to avoid that hassle.

Other choices I investigated don't have anything that would work on the fronts: Pilot Sport Cups, PZero Corsa, V700 - no luck with any of them.

So am I destined to buy A048s? Is there really no alternative for us?
 

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Al,

I'm conflicted by your experience.

At the LOG Track Day and at the LCU Elise Press launch the AD07s were run at recommended tire pressures and driven hard w/o the issues you described.

At LOG the sessions were about the same length and I saw Tony giving rides in nearly every session w/o a break.

I don't have an explaination, just sharing what I observed.

Kiyoshi
 

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Seems like those pressures are way-high....the tires don't have much car to hold up here. I've been autocrossing on AD07s with about 27-28 front and 31-32 rear.
 

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Discussion Starter #4
Kiyoshi, Stan,

I know what you're saying and I'm surprised, too. I would have expected, with only 2150-2250 lbs or so to deal with, the AD07s would have held up better with only a few extra psi (even at a measly 175 section width). Maybe my suspension is way-off, but the way the tires gave up under hot conditions (and not cool temps/moderate driving) makes me think that the AD07s are really over-classed by the rest of the chassis.

Kiyoshi: Are you certain the tires were being run at 26 psi? What about other variables (weather, pace, etc)?

:confused:
 

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I'd try lower pressures next time...maybe you were overdriving a bit? You'll be faster if you slow down....think about it!! The ADO7 is classified as an Ultra High Performance street tire. This is one step below the highest designation they use for street tires, which is Max Performance.

The AO48s are a hard compound race tire that is streetable. They are slower than some other options such as Hoosier or Kumho.

I suspect that the Elise would do well on Max Performance street tires of larger than stock size....like 205-215 up front and 235-245 out back. The fronts would need wider wheels, the backs could still use the stock width but more width would be better if that is an option for you.
 

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Au111 said:
Kiyoshi: Are you certain the tires were being run at 26 psi? What about other variables (weather, pace, etc)?
Weather at the LOG Track Day was Birmingham 90-90 (at least 90 F & 90% humidity).

Pace in the first few sessions as sedate. Tony was leading the "A" group and showing them the line. But by late AM and into the PM he was going at a good clip. Running away from alot of Esprits and all the Elans & Europas.

While I can't say for sure what the tire pressures were, I can say that the LCU guys never checked the tire pressures during the entire LOG! I drove both cars during weekend and the pressures seemed like they were near or at recommended.

Kiyoshi
 

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Discussion Starter #7
Next time I'll try dropping the pressures below recommended cold values to bring them up to 26/28 when hot and try that out.

I'm used to track tires that like to be around 200F and in the high 30s to low 40s (like the RA1), so that is quite a paradigm shift for me. I'll give the AD07s one more chance on the track before I scrap them - Kiyoshi's comments are encouraging.

Back to the alternatives, does anyone have any experience with the PZero Asimmetricos on the street or track?
 

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28 hot is where you want to be. Your pressures were way too high.

As I've said before, the car is VERY sensitive to tire pressure. I can tell the difference with in making 1lb changes.

I believe the PZero's came on the Euro Elise at one point. My friend's S1 190S had them and they are good for the street, but not good on the track.
 
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