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S13 autocross setup tire size?

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  • S13 autocross setup tire size?

    I would like your help in choosing what's best tire size for me.

    I am planning a new autocross/lapping setup below:
    Stock body S13 hatch
    Apexi coilovers with moderate 1.2" drop. -2.7/-1.5 camber (can change)
    Front: S14 LCA and 5lug knuckles with tension arms and 300zx brakes
    Rear: S14 subframe with aftermarket arms and 5 lugs knuckles
    Wheels: 17x9 +38 Koya CR-TEK

    I already have the wheels and will be running RE71R's. My question is, what size?

    I would like the best performance without having to pull fenders. Should I go with 245/40/17?

    Or can I get away with 255/40/17, which is the recommended size for a 17*9?

    What kind of spacers will I need if any?

  • #2
    245 on a 9 is pretty standard setup for street touring class cars and works fine. It's what I run on my stx brz.

    255s will fit on a stock body if you have enough front camber. 245 will be the safer bet in front but 255 won't take more than a small fender roll.

    You'll need a 10mm or 15mm spacer in front to get the tire off the coilover.


    I am assuming some sort of 200tw street tire?

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    • #3
      Originally posted by e1_griego View Post
      245 on a 9 is pretty standard setup for street touring class cars and works fine. It's what I run on my stx brz.

      255s will fit on a stock body if you have enough front camber. 245 will be the safer bet in front but 255 won't take more than a small fender roll.

      You'll need a 10mm or 15mm spacer in front to get the tire off the coilover.


      I am assuming some sort of 200tw street tire?
      Yes RE71Rs are 200 thread wear.

      Comment


      • #4
        Sorry, was skimming from my phone.

        I think 245 is the safe bet, but 255 is easily doable (it's what I've run for many years now on stock body).

        Comment


        • #5
          Originally posted by e1_griego View Post
          Sorry, was skimming from my phone.

          I think 245 is the safe bet, but 255 is easily doable (it's what I've run for many years now on stock body).
          Do you think I'm leaving a lot of performance by going 245 instead of 255? Especially on a 9" rim?

          Mind you I'm runnning 205 RE71r's now.

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          • #6
            Are you trying to be competitive in your class? If yes, it might be worth it to go with 255's.



            Sent from my Pixel 2 using Tapatalk

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            • #7
              Originally posted by Scores240 View Post
              Are you trying to be competitive in your class? If yes, it might be worth it to go with 255's.



              Sent from my Pixel 2 using Tapatalk
              I'd like to be yes. I'd need to shave off 1s over a 45-50s lap over my current setup (driver mod would also help) to reach the top.

              My current setup has stock flywheel, exhaust and rear subframe, running an aggressive 2 way on 205/50/15 RE71R.
              New setup will have S14 rear subframe, ACT prolight flywheel, 3" catless exhaust and hopefully an S15 helical or 1.5 way LSD on 245 or 255/40/17.

              I find current setup too tail happy, I can't be too aggressive both at turn in or exit or the rear steps out. I like loose but maybe not that loose.

              Hopefully with those mods I'll be able to drive more aggressively and shave another second off.

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              • #8
                How quickly do you go through tires? I'd hate to grab the 255s and find they're rubbing with your stock S13 front fenders. I suppose a big part of it is going to be how close they'll be to the spring or perch with the Apex'i coilovers, and how much you'll have to space them out.
                ~1992 240SX, SR20/Koni track day car
                ~2016 M3, daily driver

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                • #9
                  Originally posted by turtl631 View Post
                  How quickly do you go through tires? I'd hate to grab the 255s and find they're rubbing with your stock S13 front fenders. I suppose a big part of it is going to be how close they'll be to the spring or perch with the Apex'i coilovers, and how much you'll have to space them out.
                  I've had them for about 6 autocross and 1 lapping day in a year. The car is not plated and only drives on track. The wear is good except that some are used quite a bit on the outside while the inside looks new, I think that wear is mostly from the lapping and that one time the autocross track had a loop in it. guess I needed more camber.

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                  • #10
                    Seems like this guy fitted 245/40 on +22 offset and it seems like a pretty tight fit even with rolled fenders.
                    https://www.youtube.com/watch?v=B2NrtoHPfBg

                    Not sure if I should go with 255. Decision, decision.

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                    • #11
                      I have 255s on a +22 on the front of my car, just with more camber than you have. I have also fit a 9.5 +18 with a 255 but it starts to poke a bit.





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                      • #12
                        Originally posted by e1_griego View Post
                        I have 255s on a +22 on the front of my car, just with more camber than you have. I have also fit a 9.5 +18 with a 255 but it starts to poke a bit.




                        Looks Good! 17x9 I assume? Did you have to do a slight pull in the front? Do the front rub the frame rail or other when turning? Is caster an issue at all? I will be autocrossing the car.

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                        • #13
                          9 in front, 9.5 in back.

                          For autox with this car I run 17x9.5 +35 with 245 A7s. The car has s14 rear subframe so a few more mm out vs s13 subframe. The rear hoosiers rub ever so slightly. And the car just has a good roll front/ rear.

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