Tires for autocross

[yoshi37]

Hey everyone,

I have about a year of experience in autocross and am looking to get new tires. I have been running Continental ECS02 285/35R19 on 19x10 Apex EC-7's as my daily driver and for autocross. I have an extra set of 18x10 Apex EC-7's and plan on using those only for autocross and driving to and from the event (about 70 miles round trip). I recently installed camber plates and have -2.3° camber as that seemed to be a decent compromise between street and autocross specs.

From my research so far it looks like the Kumho V730 would be a good fit as I'm still learning and not going for max pace or wins. I know V730's are not the fastest tire but their cost and durability make more sense at this point while I'm still learning vs max performance.

Are 275/35R18 V730's the best choice or do you guys have other recommendations that will still last a while?

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[RTR077]

Worth a read

https://grassrootsmotorsports.com/articles/track-tire-buyers-guide/

 

[kz]

I assume you're running CAM-C - your wheels are little narrow for the class but I'd look at closeout Bridgestone RE-71RS - new version (RZ) is coming soon and those might be sold at the discount soon - look at TireRack for whatever size you're looking for.

Those were a top tire past two or so seasons, faster than Kumho by a bit. Just avoid tight fitments as they might be difficult to mount. Kumho isn't bad but generally off pace compared to top tires.

 

[Gearz]

The Bridgestone RE-71RSs are outstanding for autox but they are noisy and ride rough for the street. I'm assuming you're asking about dual-purpose tires, so I'd go with something in the mid-tier from the GRM article. The Goodyear SC3s are good, Michelin PSs are good, etc. If you're changing tires at the event then go with the RE-71RSs, especially if/when they go on closeout with the new RE-71RZs coming.

Another thing - if you have camber plates set your alignment for a little toe out at max negative camber. Change them to the street camber and they'll be toed in just a bit. I have the OEM camber plates so Min camber is around 1.5° and just a hair under 1/8" toe-in. When I change tires at the event, with that front wheel in the air I'll change to max camber (about -2.7°) and the toe changes to a little over 1/8" toe-out. It's because of the location of the steering rack compared to the strut (front steer config) and a little toe-out helps a lot with turn in and transitioning.

 

[petronix]

285/35/19 Bridgestone RE-71RS are currently the way to go and are cheaper at Discount Tire than Tire Rack, which is wierd because they are the same company. I had a set installed at a local Discount Tire a couple of months ago. Ordered them and scheduled install online.

Or from Tire Rack - Vitour Tempesta P1 P-01R for a little more $.

My RE-71s are installed on 4 rear PP1 (Bullitt) wheels. At 9.5" wheel width they are a little pinched. 10" should be better.

 

[yoshi37]

Thanks for the recommendations everyone. I ended up going with the Vitour Tempesta P1s as they appear to last longer than RE-71RS (Trying to still have a good time at autox while saving to buy a house is fun). I'm looking forward to feeling the difference compared to my current ECS02s.

 

[SBR70.3]

Another vote for the RE71RS. I use them on my Mach 1 and my GTI. Phenomenal tires and I have zero complaints about them. Another member here had a great quote about them....something along the lines of "they are boring because they excel at everything".

I was holding out for the new RZ tires, but Tire Rack said they wont be getting the size I want (295-35-18) in until mid March or later. I ordered some new RS tires and pick them up this afternoon.

 

[mavisky]

On the RE-71RS this season and set my first outright top PAX on them so they definitely work. That being said I've also run the V730 in the past and was shocked at how well they wore for the money. Was still fast, but there's definitely a few tenths between the V730 and the RE-71RS.

 

[RTR077]

Also worth a read. I learned a lot from Billy's write up.

How to PROPERLY select and size TIRES for PERFORMANCE - MotoIQ

 

[NightmareMoon]

Also worth a read. I learned a lot from Billy's write up.

How to PROPERLY select and size TIRES for PERFORMANCE - MotoIQ

Its good info.... but..

Unfortunately, it doesn't apply if you are limited by class to a specific wheel size, or really if you already have a wheel and don't want to change wheels. Also doesn't apply as much to very stiff tires like some of the 200TW we use for autocross.

Now in CAM we can choose whatever sizes fit, so it does have some merit for CAM if you're willing to pick wheels around it.

 

[NightmareMoon]

Thanks for the recommendations everyone. I ended up going with the Vitour Tempesta P1s as they appear to last longer than RE-71RS (Trying to still have a good time at autox while saving to buy a house is fun). I'm looking forward to feeling the difference compared to my current ECS02s.

That's a big upgrade. Enjoy the grip!

The P1 likes heat, and they're just bad in rain, so be very careful if its wet out.

 

[yoshi37]

That's a big upgrade. Enjoy the grip!

The P1 likes heat, and they're just bad in rain, so be very careful if its wet out.

Thanks, my next event is on 2/7 and I'm excited to feel the difference.

Any idea what hot PSI I should be shooting for with the P1? Our courses are short, normally 40-60 secs, due to lot size. I think I saw Vitour had a blog going over PSI and said 30 PSI was ideal for autocross but I don't know how big of a factor course length is but I know mine is shorter than some others around the country.

Thanks for the heads up about rain but I live in Southern California so rain is almost as rare as common sense around here. Ironically it is raining today....

 

[NightmareMoon]

For pressures.. what sizes are you running again? 10 wheels right?

 

[yoshi37]

Yea, I'm running 275/35zr18 on 18x10 wheels with -2.5° front and -1.4° rear camber.

 

[NightmareMoon]

Those are pretty short! Anyway, I'd look for hot pressures in the 32-33 front 31-32 rear range.

With pressures you can test with a temperature gauge, but you don't have quite enough front OR camber to even out heat/wear, so its not as easy to dial in pressure.

Basically test the outside shoulder, middle of the tire, and inside shoulder, and increase pressure if the middle of the tire is cooler than the average of the outside and inside, and decrease pressure if the middle of the tire is hotter than the outside/inside. Best would be to use a proper tire temp probe, but you can use a laser thermometer in a pinch, just try to take pressures immediately after finishing a run. You don't want to taint the results by rolling around the paddock too long.

Next time you do an alignment, try 3.2/2.0. I still get 20k from my street tires running >3 degrees front. Even if you stay 2.5 front, you can run 2.0 rear safely.

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