Johnny Sack

i have been reading alot of s2k related articles lately, if thats possible

i see alot of track guys and JDM race cars the run a 17x9 with a 255/40R17 at all for corners. is this because of the s2k's 50/50 wieght balance? i would imagine that this type of setup might introduce more understeer thus making it easier to do high speed cornering? i am totally wrong?

you thoughts?

Johnny Sack

man, i miss xviper.....

DerrS2K

A nonstaggered setup like discribed will add oversteer (wider front tires will stick more compared to a staggered setup thus rear tires will break away quicker). The wider tires could aid in cornering assuming the suspension is setup up for nonstaggered tires.

Johnny Sack

hmm. does anyone know why J's and other JDM tuners run this setup at the track? whats it good for?

CrazyPhuD

Rotating tires to even wear. Plus only one tire/wheel to stock, no possible mixups putting the wrong tire on the wrong corner. Plus many are running wider front fenders and is very likely they are running 275+ all around. Most tire = most grip.

The only reason that people run 255 all around is because that is the max that will fit up front with stock fenders.

Jim@tirerack

With the race car you can make it od what you want. It is hard to tell what each team was looking for though. They probably would not let you know if you were to ask.
For the regular street car the same size all the way around is not the best handling set up. It would make the cars back step out more easily and on the S2K that is not a good thing. Unless you like drifting.

FormulaRedline

For the exact same car, wider tires in the front would give more grip in the front, meaning the rears would have less in relation to the total grip of the car. This increases oversteer as Derr says.

As Jim just mentioned, a race car is a race car and not the same car we drove of the dealer's lot. If they made changes to the car that haven given it the ability to transfer weight to the back (chassis mods, suspeniosn changes, aero work) they might needed thicker rubber in the front to maintain a large enough contact patch to keep the car from understeering.

IIGQ4U

^^^ don't forget anti sway bar

Fongu

with the guys above. The race car setup is very different from a street car setup.

If I had to make an uninformed guess, the larger front tires are used improved turn in on low speed corners. Of course this would make the overall car balance to oversteer from a pure mechanical grip perspective. At high speeds, I would suspect the race cars with wings and whatnot would generate a lot of rear aero downforce making the car more neutral for high speed corners. It would be tough to tune properly and would probably include swaybar, springs, damper and probably suspension geomerty changes too to make work. At this level, all of this would be track and condition specific too. Ultimately on a track at professional level racing, front end grip and cornering speed is the limiting factor for lap times (unless you compensate with BIG power)...its whether or not you can also keep control of the car afterwards.

Amer

Rather than do 9" front and back with fatter rubber why not just go race tires? you would net better results and for cheaper.