How much grip do I want? Miata content

Hey folks,

I picked up a bone stock 1994 Miata and am planning on using it as a track, autocross, occasional fun summer car. For suspension, I think I'm going to go with the Xida Club Sport coilovers, but my spring rate choice will depend on how much grip I will ultimately have in my tires. Turbo is likely in my future but not for another year or two.

My question is, do I go with ultimate grip with a crazy wide 15 x 9" wheel setup or something closer to stock size? My primary goal is fun. At this point, I'm not a good enough driver to really care about race classes, but I guess it's something to consider long term even though I could make changes relatively easily. So, will going really wide make the limits so high that the car is less fun to drive? Will I scare the E36 M3 out of myself approaching those limits with a 245 vs a 195 or 205 width tire?

You're in luck, there's no street tires bigger than 225 width that will fit under the car without some serious modification.

Just in case that makes your decision any easier. The hot setup is a 15x9 wrapped in a 225/45-15 of your choice.

And that's what i'd suggest if you're going deep enough in the rabbit hole to purchase Xidas.

For a street car with non-V8 power, a 205 works nicely. Keeps the cost down too, and opens up a lot more options for wheels and tires. A bit less grip can be more fun on the street.

One thing to remember about the 15x9 is that they force you to use a tire size that's only available in slicks, R-compounds or Extreme Performance compounds.

For some relaxed fun, skip the turbo and go right to a V8! yep.

I'd buy a cheap 15x8 and 205/50s

Since my car is a track-only toy and eventually will run TT on Hoosier's, the XIDAs I'm installing on the car are 800/500 with big RB front bar and MSM rear.

If I were you I'd likely just go 700/400 and call it good.

But as you mentioned, you really need to determine the other variables so you can decide on spring rate. It's hard to make suggestions when you don't know what else you want to do.

I ran 235/40/17s on my old BMW 318ti.. a car with more weight and similar HP levels. With the Star Specs the car had way too much grip for my tastes and it just "stuck" no matter what you did. This is good for a momentium car, but not as much fun as something that can made a little loose

My turbo street Miata has "black and round" tires in a 205. I think they're Kumho 711s. Fun on the street for sure, and I had them on the track this past weekend just for giggles. Really slippery, but in a fun way. The weird thing is that they don't make any noise when they spin. Nor do they leave rubber on the pavement, I think they have about the same durometer as a hockey puck.

If your goal is fun, get a good suspension and indifferent tires. If your goal is speed, spend money on tires.

IMO installing a Koni/GCS setup along with a set of 15x9s and Rivals turned my '94 into the car it should have left the factory as. 8)

I thought grm was able to squeeze 275s under theirs without much modding? I vote 205 with a 15x8

275s are not available in a street size, that's a Hoosier.

And, 275s aren't going under there anyway without a baseball bat and probably a sawzall.

PS - I really really wish I had the car in your picture. Congrats on the purchase.

I personally don't really care for the stretched look at all, and probably wouldn't even look at putting a 205/50-15 onto a 15x8 inch wheel for street use. In my humble opinion, tires to generally look best on wheels at least as wide as the "measured" rim width but no wider than the maximum "recommended" rim width. Which for a 205/50-15 is typically going to be a 15x6.5 to 15x7.5 inch range.

I would also probably just stick with a 205/50 tire for non-competitive uses, since simply changing rubber compounds will have more overall effect on performance than changing tire widths anways. But if you're also concerned about upgradability should you change directions with the cars use at all, the 225/45-15 are typically measured on a 7.5" rim, allowing both tire sizes to meet my criteria on that size of wheel. If you prefer, or at least don't mind a slightly stretched look with the 205/50-15 tires, the 15x8 would also work fine with both tire sizes.

Pretty much all the Miatas I tracked including the current one were running 205/50/15s. Easy size to get, more grip than stock but not so much that you make a really big hole into the scenery when you misjudge the levels of grip.

Yep, 205/50 on an 8" is STRETCHED!

More aggressive tires tend to run wider within a given section width. Im pretty sure i could find a 205 that would look stretched on an 8.0. I have some 245/40/17s that look almost completely square on an 8.0 wheel too.

Mine is on 195/60(?)/14 dunlop star specs, FM springs and Konis. For a car that's just about fun and learning, it's got plenty of grip and it's cheap cheap cheap. You could always go this route until you figure out whether or not a turbo setup is in the works...

If I was running street tires on xidas I'd be getting 700/400 for rates with 15x9 wheels and 225 rivals.

I wish I could've tracked down some aggressive offset 15x7.5 wheels to stay within STS rules.

I really like the look of the smaller 13" and 14" wheels, but tire selection makes them impractical.

z31maniac wrote: Yep, 205/50 on an 8" is STRETCHED!

Look at all that stretch you hard-parker you!

Vigo wrote: More aggressive tires tend to run wider within a given section width. Im pretty sure i could find a 205 that would look stretched on an 8.0. I have some 245/40/17s that look almost completely square on an 8.0 wheel too.

Well OP is talking about turbo's, auto-x, and track time in the cars future.

I figured it was a safe assumption he wasn't looking for 60k mile touring tires.

z31maniac wrote: Yep, 205/50 on an 8" is STRETCHED!

It is. Only slightly, but just enough that l personally think it would look a bit better on a little narrower rim.

Leafy wrote: If I was running street tires on xidas I'd be getting 700/400 for rates with 15x9 wheels and 225 rivals.

Agree completely (unless running at Lincoln then get rs3's) I don't know why you would spend the money on xidas and not buy good tires to go with them. If you're even considering a turbo, you'll be kicking yourself for not getting the 15x9's as you will want them for sure. Even with stock power with 700/400 springs, I had to run no rear sway and big front bar to be able to put the power down while autoxing.

And the 15x9s are great to mount 225 hoosier H2Os on for when you decide to be a man and (cut the live E36 M3 out of the car to) race on 275 hoosiers mounted on 15x10s.

allofit

Who cares what it looks like? A 205/50/15 will typically always be faster on a 15x8 rim vs a 15x7.