Jaku

even with 15mm spacer, 225 won't rub the fender (or even 25mm spacer i say cos i've tried +55 with 255 and it only rubs the fender liner clip on stock suspension)

and you know you can only use up to 10mm to stay +55 offset wihtout any points in s2k challenge, so you are safe

and like i said, test suspension parts one by one, so try without spacers before you decide to go with spacers or not

the full lock clearnace is not a big deal, just remember not to turn full lock, there might be a chance it won't rub cos i had this setup before and i didn't have rubbing issue, maybe 9" with +63 will rub

Antonov

How exactly do stretched tires provide greater lateral force?

JstnRyan

I think that was my misconception when first posting in this thread. It seems that this would be somewhat of a special case, where the "225s" in question are considerably wider than would be expected, resulting in a tire on a rim with more "proper fit" than actually being stretched.

Jaku

i would like to know the phisics theory behind it as well

it was just couple positive results i've seen and heard caught my interest on this

rob.ok

My advice would be to jump right into the non-staggered neighborhood when its time to purchase new tires. The wing should be sufficient, you just will have to make adjustments to balance it out.

Jaku

he is calculating his points advantage for street class, thus many thoughts what's best with limited mods

rob.ok

Oh....I guess I missed that part. Then yeah.....it sounds like the best option plus it leaves the door open to go to the next level.

VitaRenovatio

Well as far as the R888s, I hear they are quite a bit wider than street tires, even the NT-01. They are 9.1" wide as measured on a 7.5" wheel. The recommended range is 7-8.5" but I bet the optimal width is even wider, as Emilio has shown.

This is my theory: If the tire width is 9.1" wide, then it is being squeezed by the 7.5" wheel. On a 7" AP2 front wheel, I feel like this would cause bulging of the tire and compromise the sidewall stiffness and "squareness" of the tire (kind of like how autocrossers try to fit huge 275 width tires on 7.5" AP1 rear wheel). This would decrease the "sharpness" of the tire (interpreted as "crisp" turn-in) and also probably cause uneven wear, probably in the center section at optimal tire pressure, as if the tire were over-inflated; but decreasing tire pressures would reduce performance.

If I were to guess, a wider wheel would increase the spring rate of the tire, increase the crispness of turn-in, increase feedback, produce more even wear, and most importantly increase grip.

From my previous two sessions on RE-01Rs, I feel like even 225 RE-01R's are being pinched by 7" front wheel...

VitaRenovatio

Yeah, Jaku has been helping me immensely on planning my Street Class build. I know I'm just a beginner, but at least I can have a car that should be competitive with Emilio and Dino's cars, for relatively cheap:

1.25 = APR GTC-200
3.50 = R888
0.25 = CR Front
0.00 = 2008 front spring
0.00 = SPC Camber (-3.0 F/R)

Antonov

Judging from Toyo's website, it seems as though they recommend running a 225/45/17 on a 7.5" wheel.

Other things to consider is the fact that rear wheels will be somewhat heavier, plus the $ spent on the wheels, plus making them fit.

In your particular case (S2000 Challenge Street Class), I think it might be worth the compromise since ultimately you will need more front grip but don't have the points to run a proper front tire.

Having said that, I am of the opinion that stretching radial tires is not the proper way to maximize mechanical grip. Racers in the past stretched rubber to maximize grip with bias ply's, but modern day radial tires are not designed to work that way. I can go on and on, but I suggest you read "The Racing and Performance Tire" by Paul Haney.

Always do research on your own, as many times inaccurate information is posted on public forums.

Dino