Will 255/40/17 tires fit on an N/A Miata?

I'm going to try to get out and autocross more next year, and debating what to do car/class wise. My '96 Miata is beyond Stock class rules(and I have no desire to go back that direction), but I really don't want to go all the way to CSP(nor do I have the $$$).

It looks like I'd get my but whooped by the S2000 and MX-5 in STR, but locally it may be a fun place to play, and I may not be that far off the pace - if I can fit the tires.

Looking at Tire Rack for the specs on the Direzza Z1, if I go with a 255/40/17, I'd be just over 2" larger in diameter than the 195/50/14 I'm running now, and I'd have to be able to fit a 8.5"-9" wide wheel. Will it work?

I know going down to a 225/50/15 would work, but the Direzza isn't available in that size, so I'd have to go to a 215/40/17. Or maybe a 235/40/17?

Hankook also has the R-S3 in a 225/45/15 which would work, but I'm afraid it won't be enough tire, as it's a full 2"-narrower than the 255/40/17?

Does anyone have any experience???

I'd be tempted to try to end up in STS rather than STR, unless your prep level sticks you in STR right now. either way, I'd try to stay with a 15" rim rather than try to stuff a big and wide 17 in there. look at the 6UL rims, they go up to 15x9" and will fit on a Miata, and that should let you stuff as much rubber in the wheelwells as they will take.

There's a suspension comparison in the November GRM, with Tom Heath's vinyl-wrapped Miata. I was surprised to find that car is running 15X9 wheels under stock fenders...and according to the article, they plan to run massive 275/35 race tires on the same wheels.

Yeah, I read that too, which is why I thought there might be hope for me. Unfortunately, there just isn't much available for short, fat, sticky, street tires.

My car has a Torsen, so no STS fo me(and I really don't want to swap it out).

For an NA Miata the 225 Hankook on a 15x9 6UL would be ideal.

don't forget, your car makes no power but weighs much much less then an s2k or an NC Miata. The kooks will be plenty of rubber and they work amazing on 9" wheels.

Well I just checked the Nat's results for STS vs. STR, a '91 Miata won STS with 124.028, while an '09 won STR with 123.663 - certainly within range of driver-skill, if not weather/condition related.

The fastest 1.8L NA in STS was 3rd-place with 124.819, if we ASSume that a 1.8L with Torsen would be faster than one with an open diff, then maybe the gap isn't as wide as I first thought...and that's on 225-wide tires.

I didn't know that the torsen keeps you out of STS. in that case, 15x9s and the biggest rubber you can fit and then drive the wheels off it

Luke wrote: There's a suspension comparison in the November GRM, with Tom Heath's vinyl-wrapped Miata. I was surprised to find that car is running 15X9 wheels under stock fenders...and according to the article, they plan to run massive 275/35 race tires on the same wheels.

The reality is that I've already run the 15x9s with 275 Hoosiers at several events. I had to roll the fender lips and so would you, but it's completely possible. Easy, even.

The problem is that Hoosiers are not an option for the street, and it's hard to find regular street tires wide enough to justify the 10x9s.

245/40/15 Nitto NT-01s on the 10x9 6UL wheels fit beautifully, and work fine in the street here in Florida. If I lived in Ohio or New York, I'd hesitate with any R-compound.

I haven't messed with 17s on my car, but may try the wheels from the MINI Cooper S project just to see how they fit. They're 17x8 with a 235/40R17 IIRC.

{edit} Just adding a couple of pics.

I've rolled the fender lips again for just a whisker of extra space. Under the right combination of suspension compression and tire deflection there's a slight rub on the spring perch in the front, but it's pretty minor. I could clearance the perch, but the rub is really pretty minor and only happens under specific conditions.

We got some of those 275/35/15 Hoosiers out of the trash pile at the local track and mounted them on some old XXRs (or Sportmax, whatever they are, those wheels that make Rotas look baller) from CL and test fit them on our Nismospeed Miata. The wheels are 15x8+15, and aside from the pain of actually mounting them, they actually fit under stock fenders. We had to pull them a little bit, but there's no rubbing.

" Unfortunately, there just isn't much available for short, fat, sticky, street tires."

Reading that, I instantly thought of Avon, and the short, fat, sticky tires I see on vintage race and street cars. Don't know who carries them, or the cost,, but, they might be worth a google search or two.

Tom Heath wrote: 245/40/15 Nitto NT-01s

Stop teasing us with tire sizes that we WISH existed. You mean 225/45/15 right?

2002maniac wrote:

Tom Heath wrote: 245/40/15 Nitto NT-01s

Stop teasing us with tire sizes that we WISH existed. You mean 225/45/15 right?

Yeah, you're right. That's what I get for trying to keep up with the message boards on a Monday.

225/45R15 is correct. They look VERY wide for 225s, especially when mounted on a 9" wheel.

IIRC sticking anything bigger than 15s on a Miata is considered to be detrimental to the handling, rather than improving it.

But that might be because of the type of 17s most people stick on Miatas...

Wow, those tires look WAY bulgy... how do you not have a bunch of sidewall slop with a setup like that?

ReverendDexter wrote: Wow, those tires look WAY bulgy... how do you not have a bunch of sidewall slop with a setup like that?

Tire pressue and stiff sidewalls. They're only 35-series sidewalls.

I can guarantee that with firsthand experience you would not describe the ride as "sloppy" in any way, shape, or form. Come out to the Dixie National Tour in March, I'll give you a ride in it.

I've set Elvis up to theoretically run a 255/40-17. It required welding on the battery box though. Just to answer the original question :) On an NA, it would be harder.

I"m telling you guys. The Hankook 225 loves a nine inch wheel. With a mega squirt, torsen, 15x9 6ul's with the kooks and an otherwise STS build an NA Miata could absolutely compete in STR. I'm talking national level, course dependent but still.

Stop teasing us with tire sizes that we WISH existed. You mean 225/45/15 right?

First thing i did when i saw that was google it and feel disappointed. :(

1slowcrx wrote: I"m telling you guys. The Hankook 225 loves a nine inch wheel. With a mega squirt, torsen, 15x9 6ul's with the kooks and an otherwise STS build an NA Miata could absolutely compete in STR. I'm talking national level, course dependent but still.

Very encouraging!

Completely out of my price range & driving skill to take it that far though. :D