JCrane82

iTrader: (3)

You have to realize that the autocross guys that are putting 275 or 285 wide tires on a stock wheel are using R compound track tires. These tires will have a much stiffer sidewall than even the performance summer tires that most people use. You would never want to put that wide of a tire on the stock wheel if it wasn't a R compound. Stay within the manufacturer's recommendations for wheel width and you will have no issues.

I doubt those autocross guys are trimming or rolling fenders since that would be against SCCA Solo regulations.

J8635621

iTrader: (10)

Can a mod please change his name to Mr. Sidewall Stiffness?

JCrane82

iTrader: (3)

Here we go again............J/K

I don't feel like arguing today.

Mr_Pieper

You're making my sidewalls so stiff.

JCrane82

iTrader: (3)

Never knew J had that effect on you. Watch out J, Mr. Pieper might become Mr. Poker

Danmn858

iTrader: (10)

ay,
18x10 +4 Front and 18x11.5 +4 Rear

Will it fit?

Mr_Pieper

Stop asking Dan. Showoff.

greyEight9

ive been looking for rims for a good month or so now and found som nice work 11r's i was wounder what offset to go with. i dont want them to stick out or be sunk rediculously in. they would be

18x8.5 all around in a +30 or +38 offset
i have stock springs and coilovers but woul like to lower maybe 1 1/2 or 2 in in the future, no brake upgrade but i plan on doing stoptech front kit next summer. im not sure tire wise what i plan on doing, im open to suggestions

JCrane82

iTrader: (3)

my vote is +30. Planning on running 245/40R18's (I am assuming they are 18's)?

greyEight9

yea there 18s, i will probably go 245s. would i be ok clearance wise with 30.

J8635621

iTrader: (10)

Lower it first then get 9.5 +30s

greyEight9

is there that much room without rubbing for 9.5

Mr_Pieper

There is room at that width. I'm at +20 with a slight roll.

A big brake kit on an 8 isn't necessary unless you want the look.

greyEight9

so would the +30 at 8.5 or 9.5 be the same fit wise(would it sit flush or stick out, etc)also i dont want to roll or shave. sorry offset confuses me i have a very loose grasp of it.
beake kit would be for looks

Mr_Pieper

The stock wheels are 18x8 +50. To get an idea measure out 20mm wider for a +30 and then add half the extra width of the new wheel.

JCrane82

iTrader: (3)

After asking if a +30 ET at 8.5" or 9.5" would be the same fit....it seems you need to do some basic studying on what offset is and how it affects fitment. Check out this thread for starters:

https://www.rx8club.com/wheels-tires...ls-rx8-232206/

If you need more information on what offset is in what it means, check out tirerack.com and read their informative articles on wheel fitment.

greyEight9

ok so i took a look at that thread, i understand what positive and negative offset is a little better now. if im thinking right anything lower than stock offset will push the rim out?

Mr_Pieper

That's correct. It moves the hub closer to the inside of the wheel. You can get a tape measure out and try to visualize things if you understand it a bit.

greyEight9

ok so like you said earlier if i was going with 8.5 +30 it would be 20mm plus 1/2 in and if i went with 9.5 it would be 20mm plus 1 1/2 in.

Mr_Pieper

1/4 inch for the 8.5 and 3/4 inch for the 9.5. You have to cut it in half because the extra width is spread evenly to both sides of the wheel.

greyEight9

oh ok, that would put me at roughly 1in out with the 8.5 and 1 1/2 in with the 9.5. how does height affect it though? it says for every 1 in u lower you can go down 5mm in the tread JCrane showed me

Mr_Pieper

You can figure tire height like this: 245/40r18= 245*40*2(2 sidewalls), then divide by 25.4 to convert to inches and add to your wheel size which is 18. So this size would be about 25.7 inches tall. Tires sometimes run bigger than others but this gives you a general idea where everything will sit.

A 245/40 will be slightly stretched on the 9.5 but will fit well on the 8.5. A 255/35 may work well on the 9.5.

greyEight9

oh ok this is all making a lot more sense, the only part im not sure is if i lower it how would that work

JCrane82

iTrader: (3)

Anything is pretty much possible if you are open to modifying the fenders. Inner fender well trimming or fender rolling is easy. What wheel/tire package do you want/need? Are you just going for looks, or also performance? Do you think that wider wheels/tires are automatically better than narrower? It gets even more complex when a "perfect" autocross setup is different than a "perfect" track setup.

Just a couple questions to get you thinking about what you really want to accomplish. If you answer some of those, we might be able to provide better opinions on which path is best. Just remember that these will be just that......opinions. And when it comes to your car......YOUR opinion matters the most.

greyEight9

i see, im more focused on appearance with a little performance, i dont plan on doing any track or autocross. its just a street car but i want it to be usable and able to destroy corners. if i drop it it would only be 1-1.5 in