Street Class tires

[10gt61]

In discussions I have had so far with potential tire sponsors I have found they are very interested in what tires we at OTA like to use.
Seems safe to say the top three street tires are RS3's, Rivals and ZII's.
But what about the lesser used tires in our series?
....like the Toyo R1R's and Yokohama AD08's?
It would be great to hear opinions from anyone with experience using these tires (and any others as well).
It would be appreciated I'm sure by the tire manufacturers as well as being helpful to fellow competitors with the their choices.

Thanks

[Dave Barker]

Re: Street Class tires

Are the tire sponsors offering deals through dealers or just contingency awards?

Happy to get a contingency award but I have to drive fast enough to win one of those.

[Carguy]

Re: Street Class tires

I put some 245/40-17 Toyo R1Rs on 9" rims on my BMW 128i (daily driver) for one summer and they were toast. This is with no track days on them. The R1R tire tread is made from what appears to be 2 different rubber compounds. The primary compound was very soft and just below it was a somewhat harder compound. The primary compound wore away extremely fast and the compound below was tougher but still wore far too quickly. Mostly city and some highway driving.

I used RS3s on my CRX. The RS3s were 1st gen 225/45-15 on 8" rims and lasted the entire race season driving to the track. They had a surprising amount of tread left at the end of the season. The CRX's weight was approx. 2150 lbs and the suspension setup was very stiff, in hindsight I believe it was too stiff. As a result I never felt the RS3s were a very grippy tire and my non-ABS brakes had a tendency to lock up. I got good competition results and durability but I still preferred the NT01s in the same size. The RS3's did well in the heat, felt greasy on really hot days and under-performed in cooler temps.

On my BRZ I ran 245/40-17 Rivals on 9" rims. Except for the rims my BRZ is all stock and the front suspension is camber challenged in hard cornering maneuvers (not enough negative camber). My early impression was that the Rivals didn't feel as grippy as I hoped they would be. Over time I believe the suspension was partly responsible for less than sharp response to steering inputs (a stiffly sprung CRX spoils you I suppose). Performance and results were OK since I was getting used to a new car, but tire performance dropped off significantly mid way though the season. I flipped them just before the shootout but by then much of their grip was gone. The set only lasted until the beginning of August and I replaced them with RS3s. The Rivals fared well in cold temps and held up well in warm to hot temps.

[Saj5DJ]

Re: Street Class tires

I've a pretty good insight into streets due to the highly nerdy and obsessive autocross world.

Some notes:

RS3's are a different compound now. They heat up way, way faster, are actually useful in rain but are now prone to overheating. The autocross guys on heavy cars are spraying them between runs now. Great change for cone dodging. Not so sure it's a good change for Time Attack.

The RE71 looks to be really, really quick on some cars. Initial testing suggests this is the go to tire for this year. Seems they resist overheating, but apparently wear more quickly too. They've been lighting up the results sheet at the earlier major US events. They're also supposed to be seriously faster in the wet vs. any other EHP street tire.

BFG have just launched a Rival-S. Softer rubber and quicker warm up. I heard of some testing from last year that says, for autocross anyway, that they're very much faster. Would guess that there's potential for them to be a "one lightning lap, then overheat" tire, but we'll see.

My experience of the Rival matches Pierre. Good, but not great, then they cycled out and totally fell off a cliff. Mine actually hit the cliff after 2 autocrosses, one track day and the first OTA event. By event 2, they sucked.

The ZII Star Specs are supposed to be more resistant to overheating than the ZII. Still some guys in vette's complaining about overheating the rears, but then they spin those up a lot more at autox than track. Still guys winning trophies and looks to be faster than the Hankooks in some applications now.

AD08R seems like a great track tire from what I hear. Autocrossers didn't spend much time with it due to 200TW rule.

[thgear]

Re: Street Class tires

yeah, the R1R is not a track tire, it will melt away rather quickly.

[Greg Campbell]

Re: Street Class tires

I will be running the AD08Rs this year, after the first even I would be happy to share any feedback on the tire for the benefit of sponsors.

Also happy to chat with anyone in the paddock about the tire. Although Yokohama is a series sponsor (with contingency available) the AD08Rs do seem to be an alternative choice for OTA.

[10gt61]

Re: Street Class tires

My experience so far has been with NT05's for one year and ZII's since then.
I can't fairly evaluate the NT05's because I was still learning and not driving to the car's capabilities. Having said that, I liked them, but I understand they are "old technology" now.

I love the ZII's. I'd like to run a contingency tire, but I need every tenth I can get and I believe the ZII's are helping (and they come in my size which others do not, 275/35/18). They don't overheat, they grip and they turn in. And - they seem to last. I now have two sets which I've used the last two years and they both have a few track days left on them.

Still, I'm very tempted by the new ZII Starspecs....

[wparsons]

Re: Street Class tires

Kelly, I've heard nothing about great things about the ZII SS in comparison to the original ZII.

[gaspeddle]

Re: Street Class tires

I will be running the AD08Rs this year, after the first even I would be happy to share any feedback on the tire for the benefit of sponsors.

Also happy to chat with anyone in the paddock about the tire. Although Yokohama is a series sponsor (with contingency available) the AD08Rs do seem to be an alternative choice for OTA.

I was looking at that tire as well... I'd be interested in your feedback Greg.

[Apex177]

Re: Street Class tires

I'm probably not the best to give input on tires, but I wasn't impressed by the toyo proxies r1rs I used last season. They didn't last me very long, 4 ota events and 2 trackdays, smp was very hard on them as they seemed to have worn the most there. The other issue was they had a very uneasy feel to them mid corner, the car would get very snappy. The benefit to them was on cold or damp tracks the would heat up quickly (not so good for hot days). Now that being said, this car was new to me and they have been know for snap oversteer on earlier models. As well as I was using the stock size tires ( 205/55r16 front, 225/50r16 rear), now I'm going to a 255/40r17 all around for this season which I'm sure would help the toyos but I'm not sure if it would be enough to make it worth buying another set over the RS3s or Z2s.

[Greg Campbell]

Re: Street Class tires

... now I'm going to a 255/40r17 all around for this season which I'm sure would help the toyos but I'm not sure if it would be enough to make it worth buying another set over the RS3s or Z2s.

I would echo Serge's sentiments above that the R1R is really not suited to track use. Maybe on a super-lightweight car in the secrete sauce 195/15 size on a cold day, but otherwise they are just not up to snuff.

255/40/17 is a really popular size available in pretty much all today's EHP tires. However, since it is a popular size they can run out of stock pretty quickly.

From TireRack:

Rival - $209 each, in stock.
ZII SS- $179 each, in stock.
RS3 V2 - $152 each, in stock.
RE-71R - $197 each, back order until April 3rd
Yok 08R - $217 each, in stock

As a side note, I don't know how wide your rims are. Unless you have at least 9.5 inches you will not make the most out of the contact patch. You might be better off going with a 245/40/17. There's no cost savings over the 255, but if you are 'aware' of the snappiness and want more confidence from your tires less width is better. All of the above tires are available in 245/17 for similar prices and inventory availability. SCCA autocross guys shove massive tires on rims because they are limited in wheel width. While this is ultimately faster those set ups are very difficult to drive as a pinched tire provides very little driver feedback.

[Greg Campbell]

Re: Street Class tires

Initial impressions of the AD08R

With the season only just getting underway, I thought I would post my initial impressions of the AD08R in case anyone is still on the fence regarding their tire choice. FYI: these thoughts have been assembled from just one day of track use; a cold Spring Fling on the Fabi track at SMP. Standard disclaimers apply/YMMV.

Pertinent Facts:

Tire Size: 255/35/18 front and 295/30/19 rear
Wheels: 18x9.5 front and 19x11 rear
Car: 2009 Corvette C6
Alignment: -3.9 Camber, 1/16 toe out front. -1.5 Camber, 1/16 toe in rear (edit: as confirmed by Scott at Can-Alignment my settings were actually -3.0 front left, -3.2 front right, and 1/2 inch of front toe out... no wonder it was a tad darty under braking)
Weather conditions: Cold and sunny. 5-8 degrees C
Previous Tire: 265/305 RS3 v1

First Impressions/Road Manners:

This is a very stiff tire. Sensation of stiffness is probably a combination of the stiff construction as well as the relatively low profile and slight stretch of this wheel and tire combo. The ride feels firm on the road although bump compliance is not harsh. Noise is on par with the RS3 (if you care about such things).

Track Manners:

First session impressions are that this is a progressive tire, with a smooth/predictable transition from grip to slip, and then back to grip again. The tire does not appear to want consistent slip angle in order to be fast, preferring a neat and tidy approach. However, if you overstep the boundaries the tire has an easy return to grip and does not punish you for overstepping.

Heat Management:

No (apparent) issues with overheating. Noting that is was a cold day (< 10 degrees all day), there was no time where the tire felt like it overheated and lost grip. Lapping sessions were generally 6-8 hard laps, punctuated with a slower lap and/or a pull through the pits for pyrometer/pressure check. Corvettes are known for being easy on tires due to good weight distribution, large contact patch for the weight, and good suspension camber curve. Pyrometer readings (probe type, not infrared) showed temps in the 120-140 range, so despite the low ambient temperatures good heat was being generated.

Balance of Grip:

Lateral cornering grip was well balanced with longitudinal braking and acceleration grip. Didn't feel like I had to manage a lack of one or the other (unlike the RS3 which write lateral grip cheques that the braking grip can't match). Put another way, if you think of the traction circle the 08R has a smooth arc between braking to lateral grip levels, where as the RS3 feels like there is a dip and the circle looks more like a + sign.

Steering Response:

Much more precise and direct than the RS3. I always felt that I knew what the front end was doing in response to inputs. Immediate response to direction changes.

Air Pressure:

Will be application specific, however the 08Rs likely require less pressure than the RS3 due to the stiffer sidewalls. I started at 40 psi (hot) which was where the RS3 liked to be and was reducing pressure all day ending at 34 psi (hot). I will need additional data from a more representative and less cold day before going any further with pressures. I do not want to go too far in one direction or another based on one cold day of testing on a track OTA doesn't actually use.

Corner Balance:

Great turn in, tire likes to be trail-braked. Much better transition from braking to initial turn in than the RS3. I always felt that the RS3 would need a moment to 'take a set' in the corner before gripping. Sensation was that it would flop over, then grip. In the initial part of the corner, the 08R doesn't do this; it just grips. From mid corner to exit, the progressive feedback gives some options as to when you can apply more power.

Wear:

Abrasive SMP surface combined with full tread depth led to wear rates that were higher than I was expecting (5 sessions 30 mins each, 35 laps total). Treadwear will probably slow down with reduced tread depth. The 08Rs are reversible and can be mounted inside out to prolong their life and I am planning to do this in July/August. Current (internet) reviews suggest that the 08R maintains grip well throughout its life, and does not drop off like the RS3 or hit a heat cycle wall like the Rival.

Final thoughts:

I do not want to make grand statements based on one day of running, however based on yesterday I do prefer the 08R feel and responsiveness over the RS3. I tend to trail-brake a lot and I was always a bit frustrated with the RS3. I would be braking too hard and too late and when trying to turn in I would get a lot of understeer. I also struggled with understanding how to warm up the RS3 for a hot lap and never seemed to find that Goldilocks procedure.

The 08R appears to just 'grip and go'. On a car like the Corvette where confidence is key to a fast lap, the 08R suits me very well. Fabi lap times were good, although that is somewhat useless data as we do not run Fabi.

[10gt61]

Re: Street Class tires

Initial impressions of the AD08R

With the season only just getting underway, I thought I would post my initial impression of the AD08R in case anyone is still on the fence regarding their tire choice. FYI: these thoughts have been assembled from just one day of track use, at a cold Spring Fling on the Fabi track at SMP. Standard disclaimers apply/YMMV.

Greg, great review and great info. I am also going to be on the AD08R's this season, so I was very interested in what you had to say. Sounds like a good Mustang tire too. I'm looking forward to using them, once I "use up" last year's ZII's at a couple of MIR lapping days.

[gearhead]

Re: Street Class tires

I was out on AD008R's this weekend at CTMP this last weekend and they worked great for myself.I am running 275/30 19 & 295/30 19 on my stock 9" & 10" as my proper 10" & 11" track wheels have not arrived as of yet.They are a bit pinched but you would never know it by the way the tires performed.Tons of grip and did not fall off when they got warm.They are also livable on the street with not much more noise or ride harshness than the stock Michelin PSS's that came on the M4.

[Greg Campbell]

Re: Street Class tires

I am also going to be on the AD08R's this season... I'm looking forward to using them, once I "use up" last year's ZII's at a couple of MIR lapping days.

Have you placed an order for the 08Rs yet? I think the Canadian supply is pretty thin at this point. Tires23 had a great price (and included mounting and balancing) but they were 8-10 weeks before being in my hands. Not sure what Talon Tire has for stock. I bought mine through the Tire Rack.

I was out on AD008R's this weekend at CTMP this last weekend and they worked great for myself.I am running 275/30 19 & 295/30 19 on my stock 9" & 10" as my proper 10" & 11" track wheels have not arrived as of yet.They are a bit pinched but you would never know it by the way the tires performed.Tons of grip and did not fall off when they got warm.They are also livable on the street with not much more noise or ride harshness than the stock Michelin PSS's that came on the M4.

The stiff sidewall of the 08Rs means that you can run it pinched without too much issue (just like the Dunlop, just run a tad more pressure).