[sab123]

I've started looking at the street-class autocross tires for 1LE, and apparently the variety is not great, both in 19" and 20". 19" has more brands but they tend to be narrower for the fronts (275 instead of 285), which is probably not good, not to mention that I don't really see 11"-wide and even 10" rims in 19" size. I wonder if anyone has tried to use Yokohama A052 295/30R20 all around? Does it fit in the front?



Judging by the wear on tires from the previous owner, the car probably has some understeer in the stock form, so a little wider on the front, a little narrower on the rear should help. But we'll see how it goes with the racing alignment.



The stock Goodyear has 781 revs per mile on the front, 767 on the rear, this Yoko has 765. So the rear diameter would be very close but the front a little taller than OEM.


The section width might be very close: Goodyear front is 11.4" on a 10" rim, rear 12.3" on 11" rim, Yoko is 11.8" on a 10.5" rim. I guess changing the rim width should get it pretty close to Goodyear both ways, but squish the fronts a tiny bit taller yet.


Weight-wise Goodyear is 29 and 31 lbs, Yoko 28 lbs.

[clyde]

It's really easy to overthink this. For diameter, just make sure the fronts aren't taller than the rears (or else the computers go nuts in a bad way). The width difference impact is likely to be more theoretical than practical if you can drive the tire you have. The tire compound is probably going to have a much larger influence on what it's like to drive the car and how quick you'll be may depend more on how well your driving style and tire match.

I don't think there's any firm consensus on whether the Bridgestones or Yokohamas are faster on this car. Looking at results from last year, it was mixed. The tires drive a bit differently in ways that suit different styles. Bridgestone seems to work better for drivers that are more precise and may have a tiny bit more ultimate grip while the Yoks are more forgiving, tolerant of a little extra slip angle, and put power down better.

There's also the Nankang CRS V2 and Kumho V730 that could be good options depending on your use case. The Falken RT660 is probably outclassed by the newer tires, but they're still really good and have pretty amazing wear characteristics.

To make buying tires today more fun, be aware that a Bridgestone 305/30-19 RE71RS is expected by April (which does mean it will actually happen, but it might).

FWIW, I am annoying my codriver with multiple texts every day as I go around and around on what tires to start with. Since the first round is on him, I should probably tell him to place an order for me to pick up at the nearest Tire Rack warehouse and I can find out what they are when I get there.

[Christian1LE]

The CRS V2 and A052's are faster on track than the Bridgestone RE71RS. The CRS and A052's are also available in 315/30/18, RE71 is not. I'm not familiar with their sizes in 19" though.

From my experience on track the OEM SC3's are almost identical to the RE71RS in laptimes. Granted the RE71 is on 18's vs 20's and they are 295 square vs 285/305 stock. I have no data for autocross.

[sab123]

I haven't tried RE71RS myself yet, but compared to the previous RE71R and to V730, A052 were quicker on my previous car (RX-8).



But RE71R definitely lasted longer: they kind of fossilized over time, and I've had them on for 3 seasons (RX-8 isn't competitive any more in CS anyway, so I didn't care so much). I think after wearing about half-way, RE71R either had a harder compound surfacing or just hardened over the winter, and then lasted very long. A052 lasted a season, then had a harder compound at the end (the side of the car that had more worn tires had a good deal less grip), then quickly corded. V730 didn't quite wear out in 1.5 seasons. When new, I think they were kind of close to A052 but not quite.


An interesting thing is that on V730 the car felt more understeery than on the other tires, I had to turn up the rear rebound by 1/10 (a quarter-turn on Koni) to compensate. Maybe they react differently to the camber difference between front and rear (I've been running less negative camber on the rear). Or maybe it's because I've got them a little narrower, 245 instead of 265 on the previous tires, and that made them react differently to the camber.


But V730 don't seem to be available in 20". And given that the 19" options aren't great either, and aren't any cheaper, I think I'm inclined to stay with 20".


I don't plan to take this Camaro to the track anywhere soon if ever, but my experience there is that all the streetable tires overheat badly on the track, and just going with the real race tires (like say Hoosier R7) is not only more fun and safer but they also end up lasting longer. When we were running on Hoosiers in stock autocross, the worn A7 left over from an autocross season worked very well at the track in cold temperatures (in the 30s or 40s) at the end of the year :-)

[cdrptrks]

Originally Posted by sab123

I don't plan to take this Camaro to the track anywhere soon if ever, but my experience there is that all the streetable tires overheat badly on the track, and just going with the real race tires (like say Hoosier R7) is not only more fun and safer but they also end up lasting longer. When we were running on Hoosiers in stock autocross, the worn A7 left over from an autocross season worked very well at the track in cold temperatures (in the 30s or 40s) at the end of the year :-)

SC3s are designed for the track and don't overheat too badly on track in my experience. For 20 to 45 minute sessions it can be helpful to do a cooldown lap after every 2 or 3 hot laps if really using the tires close to their limits. At my home track I set my personal best in one direction at the end of a 45 minute session (with cooldown laps) although the tires were slightly less grippy than towards the beginning of the session because they were a little hotter than optimal. I find it very hard to get the SC3 tires hot enough for autocross except when it is hot and sunny outside. Goodyear Supercar 3R tires take quite a bit longer to warm up than SC3s but they stay consistently fast once warm for 30 minute sessions without cooldown laps in my experience. I have heard A052s are only good for one hot lap on track before they overheat on our cars.

Hoosier A7 warms up almost instantly vs. R7 that takes quite a while to warm up. Hoosier R7 and Supercar 3R are both have the same warm-up rating here: https://grassrootsmotorsports.com/ar...-buyers-guide/

Originally Posted by Christian1LE

From my experience on track the OEM SC3's are almost identical to the RE71RS in laptimes. Granted the RE71 is on 18's vs 20's and they are 295 square vs 285/305 stock. I have no data for autocross.

Interesting, that's good to know. The article above rates SC3 TT pace as B vs RE71RS TT pace as A.

[JamesNoBrakes]

I went with the 19" Falken 660RS in 295 width, based on availabiliy. I didn't want to get to spring and not be able to spec tires. The only other option was 285 RE71s. Not a lot of options at these wheel sizes. These are both sticky enough tires that they shouldn't be driven on the street though, unlike the SC3 IME. The SC3 doesn't do great on the street, but it will last at least 10,000 miles IME.

[Msquared]

If you want to go fast in a "street tire" (UTQG 200 treadwear) autocross class, then the only two tires to consider right now are the RE71RS and the A052. Those running the Bridgestone right now in F Street are running 285/35/19 square. Those running Yoks are running 295/35/19 square, or that in the back and 275/35/19 front, or 295/30/20 square. If you're running a class that lets you change wheel widths - like CAM-C - then you want 18x12 front and rear and either the 315/30/18 Yok or 295/35/18 Bridgestone.

The Nankangs probably aren't far behind, overall. I don't know about the V730s. However, the vast majority of the trophies in street tire classes at Nationals last year went to drivers using the Yoks or Stones.