Schoonie3

Been giving this some thought....and I have been reading the specs on different tire sizes. It seems like most people on this site who run a 19" staggered set-up end up going with 245/35 and 275/30. That may be OK with 8.5" and 9.5" wide rims, but if you run 9" and 10" inch wide, I think you need to run 255/35 and 285/30. Here is why.

1. The stock 040 have a 26" diameter. Most 245/35 are 25.8" and most 275/30 are 25.6. According to the tire manufacturers, this measurement is taken on a 8.5 and 9.5 rims. By putting these same tires on 9" and 10" rims it essentially "stretches" the tires and reduces the diameter by .2, in other words you would be running 25.6 in the front and 25.4 on the rear. This throws off your speedometer and increases your wheel / fender gap. Going with 255 / 285 keeps your vehicle "higher" and in theory allows to lower the car and still get over speed bumps and such (I know .2 inches is not all that much, but some ladies would beg to differ).

2. Toyo T1R 255/35's measure 25.8" and the 285/30 measures 26" on 9 and 10 " rims respectivley, which is perfect size compared to stock.

3. A 9 inch rim is really 10 inches wide overall (they measure the width of the bead), so logic tells you you want a tire with a section width of at least 10" front and 11" rear. The 245/35 only have a sec width of 9.6" and the 275 are 10.6", while the 255 measures 10.1" annd the 285 measures 11.2". Going with 255 and 285 prevents both the "stetched tire look" and also minimizes the chances of curb rash.

Now for the negatives of a 255 / 285 set-up.
1. They cost a few $ more.
2. Far fewer manufacturers make a 255 / 285 combo.
3. The wider tires (especially the 285 rear) might cause more rub issues.

Can anyone give other reasons to go with either set up?

Thanks

pdxhak

iTrader: (2)

I went with 255/35 on 19x8.5" all the way around

Red Devil

I think many, including myself, would tell you to not go staggered to keep the balance of the car.

But on your 9" and 10" setup, I agree with 255 and 285 combination.

PhotoMunkey

Do NOT forget to check the your new tires' load rating. Some larger 19" tires are actuall rated lower than the 225/45-18s which come on the car. For example, my OEM Dunlop SP Sport 8090M is rated at 91W SL, which equates to a 1356 lbs of weight carrying capacity. A 245/35-19 Bridgestone RE01-R, by all measures a better, higher-performance tire, carries a lower 89W load rating, and can only carry a little more than 1200 lbs! Tire Rack is recommending staggered 19" fitments for the RX-8, but is recommending LOWER rated front tires.

Personally I'm shooting for the Bridgstone RE050A Pole Position, which is a perfect 25.9" tire on an 8.5" wide rim, so it's the same diameter as the OEM tires, AND it carries a HIGHER load rating, AND will improve cornering by virtue of being slightly wider and using a grippier rubber compound. Issue solved. I will also NOT have to retune my suspension to compensate for understeer due to the tire size differences.

XDEEDUBBX

245/35/19
275/30/19
Toyo Proxes T1R's.
I love my setup.

EZZY

i had that setup when i had the 19" too...

Kel Rx8

mad #'s thrown around LOL

time4akshun

That setup is on order for me. It is recommended by my dealer for 19 x 8.5 and 19 x 10.0. Toyo T1R's.

Chamberlin

iTrader: (1)

Thanks for your info Schoonie.... I just came into four 19X9" wide rims, and I am concerned that I might have rubbing issues in the front, but it sounds like I will be OK with 255/35 all the way around. I really want to have a little meat hanging over the edge, but obviously I can't go too wide in the fronts, and I would like to keep all the tire sizes the same. Now I just gotta take out a loan to buy some tires...

-C

Bkmckay2

I too was looking at 19x9's. Does anyone have any other combinations besides the 255/35 that do not require rolling of the fenders?

ac3mastuh

iTrader: (1)

well that all depends on the wheel itself. A +46 or so offset would not need rolling. A +22 would probably not even come close to fitting. Just make sure to leave enough space. To achieve the same "outwardness" (Low offset+skinny tire) or (High offset+wide tire). Space in the suspension would be the only thing that changes. a +30 with a 235 tire would give you the same outwardness as a +40 with a 255 no matter the rim

Chamberlin

iTrader: (1)

fortunately, the wheels I got are all +45 so I should be OK with the 255 tires... the suspension is getting changed to JIC coilovers, but I doubt they will interfere anymore than the stock...maybe less.. thanks all who replied for us 19x9 guys...

ac3mastuh

iTrader: (1)

with +45 and a 255 tire, geez you're only going to stick out an additional 20 millimetes than stock. Thats about .8 inches for us SAE guys