Mark Leger

I have a set of 18s for an 08 C6 Z06 and a set of factory rims for my car (18 front and 19 rear). What would be the best recommended set of tires I could run for autocross as far a 200 tread wear rating is concerned? Also considering to just slap scrubs on the 18s and run them in autocross and then in road courses. I mostly participate in road courses but I'm trying to do autocross to just to get more seat time.

cpt11gs

Either the BFG Rival S, or the Bridgestone RE71-R. I’ve run them both on my 2011 Grand Sport for SCCA AS Autocross. I do prefer the RE71-R, but with those you are currently limited to a 305/30-19 rear tire. Rival S also comes in that size, but if you move down to an 18” rear, you can get the 335/30-18 Rival S, which is good at putting down power. Both have the 275/35-18 fronts.

Chris

chetly

Bridgestone RE-71R or BFG Rival S

STANG KILLA SS

Rivals

the RE71s dont come in mens sizes

PRE-Z06

I’ll gladly give up the 30mm in the rear to run the ‘Stones, didn’t care for how much longer the Rivals took to get up to temp especially when cooler. Also didn’t like how soft the sidewalls were, though have not run the 1.5s yet to see how much they help with steering response.
https://www.beyondseattime.com/bfg-r...re71r-round-2/

ttx350z

I dont think there’s any fast 200 TW for the widebodies in 19”. Better off using the 18’s for autocross and using 19’s for track tires since you can get NT01’s or R888r in that size.

I tried a couple of setups as tires wore out and got replaced during last years autocross.

275 RE71/325 RE11 was such a mismatch. It was a snap oversteering son of a gun. Do not recommend at all. Push the front end 75% and the back would come swinging around. Bought some 18 wheels to run Rivals after that.

275/335 Rival S huge improvement over the RE11’s which isn’t a surprise. It was better all around but still understeered. It got better as it warmed up, but temps in the 30’s meant they never got to operating temps.

275 RE71/335 Rival S this setup actually worked really well in the 30F weather. Car was very well balance, with slight midcorner understeer if you had to much steering angle that was easily correctable. This setup got me the fast time of the day which I was shocked as I easily beat out the usual fast guys (Elise w/ RE71 & S2000 CR w/ RE71).

The first autocross for my area this year is in 2 weeks. I’ve got 315 Rival S 1.5 fronts and 335 Rival S rear for this year. I will update after said event.

Size for size, I would give the RE71s a nod. But I still have to see what the difference is with the wider Rivals. I would expect the stiffer Rival S 1.5 with 40mm more tread on each tires would make the difference and than some.

talon95

Here's a test Vivek did.

https://www.beyondseattime.com/bfg-r...re71r-round-2/

Dirty Howie

What size wheel were you running on you Rival/RE71 testing.
What size whee are you getting for the 335/315

Will be very interested in your experience/data on this.


DH

STANG KILLA SS

i think every single vette and camaro in the Optima series runs the rivals.........................

PRE-Z06

Interesting you say that about the RE71/11 combo as buddy won regional AS class last year in both autocross and time trials with that set up on his C6Z. I’ve ridden with him on track too, only difference is he ran 285/30s up front.

Set FTD at last event of the year with other buddies CAM-S GS on square 335s, but don’t think that would have been possible in the cooler temps had we not been co-driving and used blankets. I do plan to buy a set of 1.5s for my 18” wheels to run for time trials, but plan to use the RE71Rs for autocross still.

fleming23

Some are on 19" wheels and RE71s. Its pretty comparable even at the narrower width. Not sure how the Rival 1.5 will stack up yet though.

RX7 KLR

BFG just added the 305/30-19 and 275/35-19 Rival S v1.5 to the line up.

ttx350z

Good question, shouldve added that.

Fronts:
275 RE71 are OEM 18x9.5
275 Rivals were on 18x10.5
315 Rival 1.5 are on 18x10.5

Rears:
325 RE11 on OEM 19x12
335 Rivals on 18x12

PRE-Z06

The drawback of the square 305mm 19” set up on the road course is the mass is further from center of rotation and being taller hurts gearing slightly over 335 18”. The 1.5s are just a different carcass is my understanding, so not sure they’ll be any faster as the compound hasn’t changed right?

Dirty Howie

Thanks. Now even more interested in your 315/335 Rival results. I am considering the 10.5/12 inch instead of the 11/13 which seems more common.


DH

ttx350z

Heres the 315 on 10.5

ttx350z

That’s interesting. I let another driver that is a usual suspect for FTD drive my car and warned him about the oversteer. He spun it on both laps he attempted.

PRE-Z06

Wow, how old are the tires? What’s your suspension setup/alignment? Tire pressures?

I ran the Rivals (315 on 10.5&335 on 12) on my CAM-S C5 FRC before getting C6GS, have also ran 275&295 square setup, as well as R comps in the rear and 200 treadwear up front which people have freaked out about yet never have spun or put more than 2 wheels off. Driving styles of course affect results, but playing with tire psi can also affect how a car handles as well as sway bar/shock settings so to say don’t run this particular combo as it’s undriveable seems odd to me without providing more details. My buddy who’s last year’s BS national champion tested 275/315 Rivals yet chose 275/285 RE71Rs for the win, everyone who trophied at nationals in BS were on ‘stones iirc.

ttx350z

The RE71 were pretty new, like 90% tread left at the least the RE11’s were probably in the wear (definitely past the wear bars after lighting them up). Stock C6 suspension. I was used to have nothing but understeer on entry/midcorner with RE11 on the F/R so it was a very sudden change.

This was the before measurements when I took it in for new alignment after installing coilovers this winter, so they maybe a little bit skewed. Front camber was -1.2, toe -0.15, rear camber 1.3, toe -0.10. Front pressure 38 hot/rears i think around 34?

STANG KILLA SS

ive run the rivals 315 square on 10.5s. worked fine. no bulge or wallowing.

but grew tires of having to tip toe threw corners, and wait so long on exit to get on power.
now running 315/335 rivals on 11"/12" ive even run the extra wide R888R 335s on 12" rears.
no doubt 13" would be better, but my spoke style i wanted was only available in 12" for some reason from forgestar