Dustyvette

Hello all, time for new tires and autocross is the game. I'm driving to these meets not hauling. I have a 92 with 17" and am replacing nitto nt05's that I wore out last year. Ready for something better! Anybody a/x c4 's that want to share collective wisdom? Dustyvette

spro2395

I like the Nitto NT01's that I run on my 85. I have about 120 runs plus probably 750 street miles. I'm getting ready to flip the fronts for more wear.
​​​​​​​Joe

c4cruiser

Are you required to use a 200 Treadwear tire in the class you are running in? The Nitto NT01 would be a good choice but it has a 100 Treadwear rating. It can be driven on the street and while the tread looks to be asymmetrical, it can be flipped around for increased tread life. It's really more of a track tire, but should work well for autocross.

Look thru the Autocross and road racing section of the Forum where you can get lots of ideas.

Dustyvette

Spro2395, c4 cruiser, I will look into those .......Dusty

eschoendorff

I don't know about AutoX specifically, but I've been quite satisfied with the Nitto 555G2 series on my car

FAUEE

Lots of options, Falken RT615ks were the top dog a few years back (and if you ever drive in puddles or any sort of wetness these might be your ticket). People also seem to like the Star Spec 2s, R888s, and the Hankook RS3 but not sure which of those come in our sizes.

I've got Falken 615Ks. Haven't put them on yet, so I can't really comment on them.

JrRifleCoach

https://www.corvetteforum.com/forums...roadracing-23/

Might be a better forum to pose the question

Dustyvette

[QUOTE=JrRifleCoach;1594104148]https://www.corvetteforum.com/forums...roadracing-23/

Might be a better forum to pose the question[/QUOTE
Jrrc,that is a good idea,but I posted over there and had so far only one reply

JrRifleCoach

There are lots of autocross worthy tires. Maybe if you researched by brand and posted a more specific question.

Ive found Nitto to make an affordable dry performance tire.
http://www.sccaforums.com/forums/aft/29085
https://www.corvetteforum.com/forums...autocross.html
http://www.planet-9.com/porsche-tire...autocross.html

MatthewMiller

You have to answer this question before anyone can give useful information to you. If you have to use 200TW, then Bridgestone makes the RE71R in a 235/45/17 or 245/40/17 that you could probably use, and you would be faster on those than any other current 200TW tire. And you can still drive on the street with them. The only other competitive 200TW tire right now is the BFG Rival S, but it doesn't come in 17s at all.

If you don't need 200TW, we can recommend some streetable tires like the Toyo 888. But you need to know that your competitors will come equipped with Hoosier A7s that will be much, much faster tires. They aren't really streetable, although if you are only driving to local events you might be able to get away with driving there on them. But if the car is driven lots of other places, you would want another set of wheels and tires. So frankly, if you aren't competing in a 200TW class and these will be your only set of wheels and tires, then I suggest you change classes!

Dustyvette

MM, thank you and all for the replys. My car is stock and it says in scca any dot legal tire. To get to any autocross that I participate in is 80-100 miles round trip. I don't use this car much except for ax. Looking at your recommendations I see where to fit the wheels with a particular tire your narrowing about 3/4"? What do you think of the falkan rt615 that fauee mentioned?

MatthewMiller

Street Class in SCCA (where stock cars run) requires a 200TW tire by the rules. So although a Toyo 888 or Hoosier A7 are DOT approved, they are not allowed in Street. The RT615K, which is the current Falken offering, is a 200TW tire. They have been around for at least seven years now, so they are not at the top of the heap in terms of speed. OTOH, they offer slightly better size options in the 17" diameters. I am ***-uming you have 8.5"/9.5" staggered wheel widths? So the RT615K offers 235/45/17 and 245/45/17 that might offer useful staggered sizes. But the 235 will not only be narrower but a bit shorter as well, so keep that in mind.


But you will probably lose a second of potential speed using the RT615K compared to the Potenza RE71R or BFG Rival S. That's an unfortunate fact that can't be overcome. If you've been autocrossing for long, you know that giving away that much time before you even start the run is a killer. It depends on how competitive you want to be, I guess. Of course, it also depends on how much of the tire's grip potential you are taking advantage of, too.


It turns out I misspoke earlier. BFG does make a Rival S in 245/40/17 and 255/40/17 sizes, which should fit your wheels. They are basically equally fast, or even slightly faster, than the RE71R. They feel really different, though. That size would be somewhat shorter in diameter than your sizes, but would work well for competition. I would probably go with that over the two 17" Potenza sizes that I mentioned. You'd get a little more rubber on the pavement, and the newest Rival S has tested a bit faster than the Potenzas.


In Street Class, you actually have the option to use 18" rims in your stock widths and stock offsets (you can go up or down one inch from stock diameter, and I think they allow 1/4" difference in offsets). So if you have the budget, you could buy an inexpensive set of 18" rims that fit within those rules and maybe have a few more options in the Potenzas or Rival Ss.

Dustyvette

MM, things are coming into focus. Thank you! I've got after market fake grand sport wheels that are 9.5 on all corners. I do know what your saying ,a second is a lot of time. Really it's amazing just how close say the top 7-10 drivers are at any given ax. MM if I went the 18" route what size do you think would be best? Do you think wider is better or? I was happy the nt05's wore out . I think there are better tires out there. The nt05's lasted thru about 110 ax runs, 1 fantastic track day and about 5-600 miles of hi way . They are slick and ready for departure!

Jstockton

You might check the rules on SCCA Street class before purchasing any wheels/tires. Try to figure out where you want your car to run, it will save you a lot of trouble down the road.

If your vette is stock, you will run in B Street, you must run the original width wheel, which in your case is a 9.5 wheel. Like mentioned above you can jump up 1 size in diameter to an 18. So you would need to find 18x9.5 wheels with the same offset. This will improve your tire choices.

I run 18 x 9.5 wheel, and RE71R in a 275/35 18 - square setup in B street

Or you can run it in Cam and put whatever tire you want on.

There are tons of options in SCCA just have to read the rules and figure out how big your pocketbook is.

Good Luck

MatthewMiller

Wider is always better, but:
...what he said^. You have to pick the class you want to be in and pay close attention to the rules first!


Assuming you want to stay in B Street: If you stay with the stock 17x9.5 square setup, you can run a 255/40/17 in either the RE71R or Rival S. Both are 25.0" tall, so about 1/2" shorter than the stock 275/40/17 tires. Either will be a good fit on your current wheels, and will handle well. The shorter height will actually probably be a slight help for autocrossing (lower your center of gravity, shorter effective gear ratio, lower roll centers, etc), but might be a bit of a pain on the street for speed bumps, driveways, etc. (ground clearance). Both effects will be minor.


Or you can go up to the 18x9.5 and run a 275/35/18 in either the RE71R or Rival S. These will have the same tire height as stock, and you will add roughly 20mm of tread width. I would guess this is your faster option, all things considered. And you get the bonus of using your 17" rims and some cheap (maybe even used) tires for most street driving. You can swap to the 18s in the comfort of your garage the night before an event, drive to the event on them, drive home, and put the 17s back on for errands and other stuff. That's what I do (I'm in CAM, but we still have at 200TW requirement).


It's difficult to recommend a favorite between RE71Rs and Rival Ss. They are both at the top of the heap in terms of speed (the Rival is probably a bit faster), they are both quite streetable, and they both have lots of people touting them. The handling feel is very different between them. The Rival S has less steering feedback and is not a sharp-responding tire. It has a wide range of slip angles at which it develops max grip, so it is very forgiving. But it feels strange to some people. The RE71R is sharper and more like what most people expect a max-performance radial to feel like. But it is still fairly forgiving. It might be the better option on a car with stock (soft) suspension. Both tires put down power very well (the BFG might have an advantage here), and I think both a good in the rain (I've only driven the BFG in the rain, and it was great). But either tire is a good choice for speed.

MatthewMiller

I just realized I overlooked a potential contender. The new Falken RT615K+ (note the "plus" added to the name) is a new compound that was revealed at SEMA last November. It is due to be released for sale in March. There is no way to know yet (unless there are tests for it that I haven't seen yet) how it will compare to the RE71R and Rival S in terms of speed. But it's a sure bet that it was developed to compete with them, so it should at least be a lot closer than the RT615K was. Don't know how long you want to wait, or how long it will take to actually get them once you order some. So that's a factor as well. It will probably take a few months longer to actually get useful comparison tests (Grassroots Motorsports is usually the best source tire tests).

So, the timing is probably a bit late for your needs. But I thought it was worth mentioning these.