I'm beginning to think that I've got a problem, so I'm turning to the forum for help.

Stock track wheels (18x8F, 18x8.5R) and it seems that there aren't very many options. Kumho 710s are only available in 285 (and wider), but the 30 section means that they don't fit. That leaves Hoosier A3S04/A3S05 in 245/35, 245/40, or 275/35 sizes, and Kumho Ecsta V700s in 245/35 or 265/35 sizes.

The question of the week is, will the 275/35 Hoosiers or 265/35 Kumhos fit the stock track rims, or should I be looking at the 245/35?

Oh, I envy you guys with the 17" rims, you've got tons of options!

 

the 275 35 will fit on the track rim and I have only heard good things about the new A3S05 compound.

Also I have seen a 285/30 on a 8.0 wheel on a mazda rx-8 so they will fit.

 

Check tirerack.com, aimtire.com for available sizes. The Pirelli Corsa's have come down in price quite a bit. Toyo Ra-1's are a great choice as well and have lots of size options. A 255-265 rear width would work just fine on an 8.5" rim.

 

275 is pushing it on a 8inch wheel but it will fit. that's the size i plan on running.

 

This is my car with a 275 kumho 710 on a 7.5" wheel although it is a 17". I wouldn't say it is pushing it, the tire functions well and they are very fast.

 

The question should not be whether or not the tire fits on the rim, but rather what kind of contact patch will result. The problem with putting a 275 on a 8" wide wheel is the contact patch distortion which results under lside loading. You may actually have less rubber working for you with that wide a tire!

Back to the subject at hand. I finally broke down and bought a set of Dunlop Super Sport R compounds that Tire Rack sells:. They offer sizes for 18" wheels with a 35% aspect ratio. Check out the prices, they're hard to beat from that perspective:

 

dkmura:

How do you like the SP Sports so far? I'm planning on trying a set next, but I just can't seem to cord my RA1s (they last too long )...

 

John-

I'm afraid that I haven't even had the chance to try them yet. But they look quite promising: big, fat R-compound rubber sitting in a dark corner of the basement. It's snowing today and I may not get a chance to use them anytime soon. I think that several people have promised reviews once the weather changes and I'll be one of them!

BTW- the specs on thes SP Sports say it was molded in a 6/32nds tread. But it really looks deeper than that, so I think it'll be OK for normal driving.

 

I've been running 245/45R17s on 7 inch wheels for two years now (SpecV). I've gotten pretty decent, even wear across the entire tread face, even with a "camber challenged" (only 1.2 degrees of negative camber) car.

I'm not afraid of cantilevered tires! The problem is that the tire shop I'm dealing with (which deals with race tires all the time) had problems getting the 285/30s to seat on the bead -- on the 8.5 inch rears. They couldn't even get the tires completely on the rims on the 8 inch fronts.

 

Thats great in theory, but when the fast rubber comes in limited sizes you make them fit.

 

PDX Racer,

For A/X (I believe that's what you're into), the 275/35-18 seems to be the weapon of choice. It fits on the wheels just fine. The pyrometer says things are OK, I have near 80 runs on mine, flipped them on the wheels at about 60 runs... wear is fine as long as you use proper inflation.

BC

 

That's what I just bought for the '05 season. What pressures are you running for A/X events? What other mods (especially suspension) do you have?

 

So Hoosier is the only game in town, since there isn't a 275/35-18 Kumho.

At least the A3S05s are coming out RSN...

 

I think the sweet spot for pressures seems to be 35 front 32 rear. Give or take a little depending. I've gone down as low as 32 front 28 rear and the car got slower.

My car is set up like this right now:
05 350z enthusiast
Koni SA yellows (couldn't afford the DA's)
Hotchkis FSB set full stiff (right now)
Carbotech bobcats w/ super blue fluid
Amuse TI Y-pipe
Jic TI exhaust
Enkie RPF1 + some 23mm spacers for the front.
275/40/17 kumho 710's
home made pantyhose panel air filter

 

18" A3S04 Hoosiers seem to love high pressures. The testing I did with a pyrometer suggested way high pressures to get fairly even temperatures across the tread. I recommend spending some time with a pyrometer to get a good baseline to work from. Getting the pressures wrong will tear through a set of S04s in short order.

I have Koni SA (1 sweep off soft - front: 2 sweeps off soft - rear), 350evo front bar (medium... this is a very stiff bar, I tried full stiff but I couldn't adjust to the change), K and N filter, Stillen ehaust (without the boat anchor mufflers... following some dyno time, the car made more power without them... I had a local shop fab up some tailpipes to replace them), Enkei RPM2 (18 X 8, 35mm offset, 5mm spacer barely required on fronts), alignment revised to maximize tire wear. My car is a daily driver (albeit a loud one), so it's not an optimal A/X'er but it has proved to be a rewarding one.

PDX, will you be heading up here for our events? I hope so.

BC

 

Hoosiers (and Ecsta V700s) have always liked higher pressures.

I'm planning on it. I'm going to need as much practice as I can get!