Is anyone here running a set? What's the offset? Do they hit the sway bar or suspension at full lock? I'm not worried about the fender lip or the wheel tub because there won't be any. I'd like to be able to run something close to the standard offset of 38mm to keep the scrub radius reasonably normal.
Define Miata.
A stock wheel is 6 ish inches wide, yes?
So a 10 inch wheel with the same offset will have 2 full inches more backspace. My guess is you wouldnt have to steer to run into something. You'd be hard pressed to bolt it on and have the wheel still roll.
15x9 6UL wheels (+36) will hit the control arms before full lock.
Edit: On NA Miata
No first hand experience, but here's some info.
https://www.good-win-racing.com/Mazda-Performance-Part/61-0904.html
"Always test wheel for adequate clearance to fenders, chassis and suspension components before using these wheels. Failure to do so could result in vehicle damage, loss of control, injury or
death. First picture below is before and after same NA Miata, customer noted massive fender pull required for fitment as shown, and no fender liners, to fit 245mm wide tires."
From the bottom of the page.
https://www.good-win-racing.com/Mazda-Performance-Part/61-0904b.html
"New Gen4 6UL wheels are NOW Flow Formed for the first time, for even better strength than prior generations, and even less weight. This is a race fitment, COILOVERS required, massive fender roll and pull REQUIRED."
https://forum.miata.net/vb/showthread.php?t=616978
NA/NB/NC/ND ?
Keith Tanner said:Define Miata.
Tube frame front clip with stock NB Miata suspension and steering bolted to "stock" mounting points. Clear as mud?
In reply to accordionfolder :
Hmmm,..that picture of the 9" wheels on an NA doesn't have them sticking out all that much and I'll be doing whatever is necessary to stretch/flare/radius the fenders and wheel wells.
In reply to ProDarwin :
Then, I would think my problem would be the lower arm, too. NA and NB arms are identical except for the sway bar link tabs, I think.
I have 15x9 Advanti S1 w/ 225 Rival S 1.5 tires on my NA and it didn't require any more than a fender roll and the slightest ever pull. No issues with control arms or interference anywhere except for the fender liner.
In reply to morello159 :
What's the offset on those wheels?
+25 is usually the offset used for 15x10s on Miatas to get the inner clearance you'll need.
Here's a set of +25 15x10s with 245/40-15 tires on an NA body with fenders that will already fit a 225 on a 15x9. Due to this fitment, I never went much further. We did build a car with 15x10s and 275s for a customer with some fender flares, but it was running V8R control arms so any clearance statements would not apply.
On the Manic Miata ('96) I have 15x9 +38 Dial-Ins with 225/45 Rival 1.5Ss. Surprisingly enough A7s fit too. 2-1/2" diameter springs on coilovers on Koni Sports. No fender work at all; they rub a small bit at almost full lock.
"They" say you need a roll for 15x9s, but I did not. For an NA on 10s you can probably get away with a roll, maybe with a liner trim.
@thecarpassionchannel 
15x10
Thanks for all the input. I'll be able to do the 25mm offset, and might be able to squeak a little more. I won't know for sure until I can mock up some wheels and try things out in a few weeks. I'll trial fit them with tack welds and then final weld once I'm sure what I can get away with.
In reply to Professor_Brap :
Offset?
They look like Jongbloeds, which means +25 for a 15x10 or +36 for a 15x9.
15x9 Advantis are +36.
DeadSkunk (Warren) said:In reply to ProDarwin :
Then, I would think my problem would be the lower arm, too. NA and NB arms are identical except for the sway bar link tabs, I think.
The arms are dimensionally the same (external dimensions anyhow) but NB rear uprights have an extra 5mm of track on each side.
In reply to Keith Tanner :
Rear end is going to be a live axle ,so wheel offset will only dictate where I can weld on brackets. I can run any backspacing I want.
So the only thing you really care about is "how much backspacing can I handle before I rub the front at full lock"?
As noted, the +36 15x9s are basically there. So add an inch of wheel width, and we're looking at +25 for a 15x10.
ProDarwin said:15x9 6UL wheels (+36) will hit the control arms before full lock.
Edit: On NA Miata
Stop spreading BS man.
NA Miata, 15x9's (+36) fit fine with just a flat roll. No clearance issues. (-3 camber front, -2.5 rear)
15x10 +25 fits with a roll + pull on NA, Flat roll on an NB.
I have 15x9 +36 Dial-Ins with 225 Nexen N SUR4G tires on my NA. I had to roll the E36 M3 out of my front fenders and chop my fender liners up, and they still hit the sway bar. I was also having one wheel gently contact a one of my coil springs and had to run 5mm spacers. But my car is low as berkeley and I'm pretty sure there is something not right with my chassis, so...
goingnowherefast said:ProDarwin said:15x9 6UL wheels (+36) will hit the control arms before full lock.
Edit: On NA Miata
Stop spreading BS man.
The wheel would contact the control arm on my old Miata at full lock.
This is a quote from goodwin racing:
Tire/wheel will not clear stock front spring perches. Narrower 2.75" (70mm) Tein, JIC spring coilovers rub the tire at full lock. 2.5" (65mm) GC's and similar rub less at full lock. 2.25" (58mm) springs have no rubbing. Wheel may not clear front upper control arm when backing up at full lock, double check and use 3mm spacer if you get wheel to control arm contact at full lock/ full droop.
Keith Tanner said:So the only thing you really care about is "how much backspacing can I handle before I rub the front at full lock"?
As noted, the +36 15x9s are basically there. So add an inch of wheel width, and we're looking at +25 for a 15x10.
That's basically it. The only places the front wheels should hit would be the A-arms, the shock/spring, or possibly the sway bar. It likely will use a non-Miata bar. I'll be able to use the 25mm offset, which doesn't bugger the scrub radius much. I suppose the tire width could come into play, too. Maybe I'll pick up a junkyard rim and cut the back off and just space it out with some scrap steel to see what back space will pass and then fab wheels to match.
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