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Dusterbd13-michael
Dusterbd13-michael MegaDork
9/11/21 2:27 p.m.

So, i want to go to 245s. I have a set, mounted on 15x8 wheels. 

the wheels are zero offset and hit everywhere. However, this tire sits nice on these wheels. Good and square. 

According to goodwin. 15x8 +25 is the Miata fitment.

But, is it? What offset do i want to cram this much tire under this miata without flares or heavy hacking?

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
9/11/21 3:19 p.m.

Going from 0 to 25 offset will still leave a 245 really close to the fender lips on a lowered car, but it'll be better that what you have. The fenders would likely need to be rolled. We have club members running 9" rims on track cars so it can be done. I'll ask a couple of guys who do track days what they're running.

NickD
NickD MegaDork
9/11/21 3:26 p.m.

I have 15x9s with 245s on my NA. I believe my wheels are a +32 offset. My front fender liners are pretty chopped up and I rolled the bejeezus out of my fenders. I also run -3.5 degrees of camber up front via offset upper bushings

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
9/11/21 3:39 p.m.

I test fit the 15x10/245/12mm offset combo from my Challenge car on my Miata and they stuck out a lot.

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
9/11/21 4:20 p.m.

One friend is running 15x9, 35mm offset Avanti Storm wheels with a 225 tire. It rubs at full lock and it can rub the brake lines. I'm not surprised that it rubs with the inner edge of the rim being that far inboard.

Edit: He suggested you look at the Goodwin site for info on what sizing will fit.

 

Keith Tanner
Keith Tanner MegaDork
9/11/21 5:52 p.m.

15x8+25 is popular because it's easy to make at the wheel factory, but a +35 is a better fit for an 8" IMO. +0 is stanceomatic. 
 

I have 245s on a +35 15x9 on an NA and it works. Also 225s on a +36 15x8. 

NickD
NickD MegaDork
9/11/21 6:08 p.m.
DeadSkunk (Warren) said:

One friend is running 15x9, 35mm offset Avanti Storm wheels with a 225 tire. It rubs at full lock and it can rub the brake lines. I'm not surprised that it rubs with the inner edge of the rim being that far inboard.

Edit: He suggested you look at the Goodwin site for info on what sizing will fit.

 

Yeah, mine hit my sway bar and the brake line bracket at full lock, and I had to take my R Package front lip off

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) PowerDork
9/11/21 6:24 p.m.

E Street guys don't have this particular problem. 225/45 on a six inch wheel has it's own issues. 

Swapping these on after dinner. 


 

chief8one
chief8one Reader
9/11/21 9:20 p.m.

^ I want to see these mounted on the car. 

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) PowerDork
9/11/21 10:05 p.m.
chief8one said:

^ I want to see these mounted on the car. 

Dusterbd13-michael
Dusterbd13-michael MegaDork
9/12/21 10:43 a.m.

So, +25 required flat rolling the lips on the fenders to clear, and possibly still rubbing under certain conditions. 

+35 and a roll pretty much guarantees no rub.

Right?

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
9/12/21 2:18 p.m.

+35 can rub on the inside, according to my friend and he had 225s, not 245s. See if Keith responds with his experience.

Duke
Duke MegaDork
9/12/21 5:12 p.m.

I'm running 225/45 on a 15x9 +35mm wheel on my NA.

They ruB a bit under hard compression (sounds like fender liner) and a bit at full lock (avoidable if I back off a little; not sure what they're hitting).   I have not done any fender work and I am under-cambered. I don't think 245s would fit without further work.  NBs seem to have a little more room in back.

One thing no one has mentioned (though I assume you already have them) is that none of these will fit with stock springs. You need smaller diameter coils.

[edit] Per Keith's comment below, I am running Rival 1.5Ss.

 

Toot
Toot New Reader
9/12/21 7:04 p.m.

 I am currently running 15x10 with 245 Toyos have had a 275 before on my na.  Call Ryan at Goodwin he will get the biggest tire under your car.  I have a slight fender roll no ugly flares it still looks stock.  
 

Keith Tanner
Keith Tanner MegaDork
9/12/21 7:05 p.m.

225s will fit an NA on a +36 8" (barely), but not a 9 without rolling. They should fit on an NB on the 9s but it will likely be alignment-dependent. I don't think I've come across sway bar contact with the 9s but my track NA is not totally typical. 

Rubbing at full bump is not a width issue. There's a bump on the underside of the NA fender liner that will self-clearance :)

My V8 runs 245s on +36 9s with no rubbing most of the time. I have 3" brake ducts, they're in danger at full lock but that is more a comment on the ducts. Not a problem for a track car. 

I just put that wheel/tire set on my street NA. It has a mild roll (to clear 225s on a +33 15x8), we'll see how it likes it :)

Not mentioned is the actual tire. Tire sizes are more like approximations. A fitment that rubs with Rivals will clear with RE71s. 

calteg
calteg Dork
9/13/21 8:42 a.m.

Running 15x9 245s on my NA with a minor fender roll. They'll hit the fender liner at full compression, but otherwise fit beautifully

Dusterbd13-michael
Dusterbd13-michael MegaDork
9/13/21 8:48 a.m.

In reply to calteg :

What offset?

ProDarwin
ProDarwin MegaDork
9/13/21 9:12 a.m.

Timeout... the Pic at the top... those are not 15x8 +25 wheels are they?  The look *way* out there.

Are you looking at getting new wheels?

 

Dusterbd13-michael
Dusterbd13-michael MegaDork
9/13/21 9:34 a.m.

In reply to ProDarwin :

Yes, new wheels. Those at the top in the picture were 15x8 zero offset. 

ProDarwin
ProDarwin MegaDork
9/13/21 9:39 a.m.

Ah ok.

15x8 +25 and 15x9 + 36 put the outside edge of the wheel roughly in the same spot.  This is where you want to be.  15x10s go to lower offset again because there isn't any more room inboard (control arm rub), meaning the width is gained at the outside.  Outboard you *make* room.

 

 

 

 

Duke
Duke MegaDork
9/13/21 10:30 a.m.
calteg said:

Running 15x9 245s on my NA with a minor fender roll. They'll hit the fender liner at full compression, but otherwise fit beautifully

What tires?  I need to step up to 245s because I am definitely traction limited.

 

Dusterbd13-michael
Dusterbd13-michael MegaDork
9/18/21 12:23 p.m.

Been thinking a lot, and doing a lot more googling. Lots of contradictory information out there about this.

Which i think boils down to "it depends on the car "

 

The two wheels i yave decided on are konig countergram 15×9 +35 or a vors tr9 15×8 +20

I think this puts the outside wheel edge at the same place, doesn't it? Whic would require a flat roll, some modifications to the fender liner, and attention paid to the inside edges at full lock. 

Right?

Then comes width and price. Im running rs4 245/40/15, and probably will continue to do so.

Heres wheel pictures. I really like the vors....

Stampie
Stampie MegaDork
9/18/21 12:33 p.m.

The new Flyin Miata wheels are hot and reasonably priced.  I tried to steal a pic from FM but it wouldn't let me. 

https://www.flyinmiata.com/NB/kogeki-15-flow-formed-wheels-for-na-nb.html

Dusterbd13-michael
Dusterbd13-michael MegaDork
9/18/21 1:10 p.m.

In reply to Stampie :

I want to like them, but just don't...

codrus (Forum Supporter)
codrus (Forum Supporter) PowerDork
9/18/21 1:25 p.m.
Keith Tanner said:

225s will fit an NA on a +36 8" (barely), but not a 9 without rolling. They should fit on an NB on the 9s but it will likely be alignment-dependent. I don't think I've come across sway bar contact with the 9s but my track NA is not totally typical. 

Rubbing at full bump is not a width issue. There's a bump on the underside of the NA fender liner that will self-clearance :)

My V8 runs 245s on +36 9s with no rubbing most of the time. I have 3" brake ducts, they're in danger at full lock but that is more a comment on the ducts. Not a problem for a track car. 

I just put that wheel/tire set on my street NA. It has a mild roll (to clear 225s on a +33 15x8), we'll see how it likes it :)

Not mentioned is the actual tire. Tire sizes are more like approximations. A fitment that rubs with Rivals will clear with RE71s. 

Heh, and don't even think about Hoosiers. :)

On my 99, 225s (both Rivals and RRs) mounted on 15x9s (whatever the standard 6UL offset is) will rub on the sway bar (1.25" racing beat) at full lock.  Full lock also chews up the 3" brake ducts badly.  There just isn't three inches to spare there.

Rubbing on the inside seems to depend a lot on how much travel the shocks and bumpstops give you.  I had no issues with that running FCM revalved Bilsteins, but when I put Xidas on the car it was rubbing everywhere.

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