Need help!! Will 15x8 0 offset for on na8a???

Lochiell · Postby **Lochiell** » Mon Dec 15, 2014 12:44 pm

Just need some help/advice , this is my first nb or mx5 in general ...

Will be purchasing some wheels this arvo,

Curious if 15x8 +0 offset will fit on an nb8a? Without mods

Also... Will be buying some rota rb in 15x7 +25 , will these fit aswell?

Thanks for your time

Jeo · Postby **Jeo** » Mon Dec 15, 2014 1:13 pm

Fit is a relative term that also depends on a bunch of other variables, but yes, 8" wide wheels with 0 offset will "fit" on an NA/NB. It's probably the most commonly used wheel sizing amongst the fitment crowd.

Google "mx5 15x8 +0" and you'll find thousands of results.

hks_kansei · Postby **hks_kansei** » Mon Dec 15, 2014 1:34 pm

No, it won't fit without modification.

I had a set of 15x8+25 wheels on my nb8a, and there was lucky to be maybe 1mm of clearance before the rears clipped the guards. (of course, that was with 205 width tyres, which are about as narrow as i'd go for an 8in wheel)

the zero offset will fit, but you'll need to roll the guards, and maybe add some negative camber.

I classify fit as that you can bolt them on and call it done. No farking about with alignment, or hammering guards etc.

Jeo · Postby **Jeo** » Mon Dec 15, 2014 1:53 pm

At what height hks? I'd be surprised if they rubbed at stock height, even with a 205/50.

Height and tyre size being two fairly important variables in this equation.

hks_kansei · Postby **hks_kansei** » Mon Dec 15, 2014 1:57 pm

Jeo wrote:At what height hks? I'd be surprised if they rubbed at stock height, even with a 205/50.

Height and tyre size being two fairly important variables in this equation.

30mm lower than stock.

But, even at a higher height you'd need to take into account suspension compression.

Lochiell · Postby **Lochiell** » Mon Dec 15, 2014 5:31 pm

Nah I meant "fit" more like just bolting on rather than "fitment" or "stance", I'm not too worried about having my wheels poke out from guards haha I wanna try keep it looking legal as I can..

I only was curious about the 15x8+0 because I could get a cheap set,

So would anyone know if a 15x7+25 would bolt on better (without mods) than a 15x8+25?...
Or should I just look for a new style of wheels?
I'm looking at buying a new set of ROTA RB's (look like watanabe).. My point is, anyone know of a brand that has the same style but with more offset..?

Sorry, wheels really get me and I don't wanna buy a crap size!
Really appreciate the advice! Thanks to everyone who posts

sailaholic · Postby **sailaholic** » Mon Dec 15, 2014 6:25 pm

The offset is what makes it hard to fit.
Ie a 15x8 +36 fits easily. But a 15x8+0 sticks out another 36mm!

15x7 +25 is about the same as a 15x8+36. While the offset (+25) would give 11 mm more "poke" based on offset.

BUT! the wheel is also 1 inch (25mm) narrower then a 15x8, half of this width goes to each side of centre for you calculations. So based on rim width the 7" has 12.5 mm less poke.

So your total "poke" change from the reference (15x8 +36) will be the difference.
= +11mm (offset) - 12.5mm (width)
= -1.5mm. So your 1.5 mm further from the edge of the guard.

It will really pay off to work out what you want and do the math to make sure you know what your getting.

For reference I run 15x7 +23 on the front of a NA and I've rolled the lip of my guards. Needing it was marginal I might have got away with out it.

I believe nb guards are a touch wider.

Sent from my iPhone using Tapatalk

hks_kansei · Postby **hks_kansei** » Mon Dec 15, 2014 9:59 pm

sailaholic wrote:I believe nb guards are a touch wider.

The rears yes, the fronts not sure, if the fronts are it's a marginal difference.

to the OP, a 15x7+25 should fit without a problem, I had 15x8+25 on mine and they fit (just) without any mods. (a few mm clearance)
the 15x7, being 1 inch narrower, will have 12mm more room than the 8inch did, so it would be fine.

My next set of wheels I'm wanting 15x7+25.

For reference, factory on the NB8A is 15x6+40

Jeo · Postby **Jeo** » Mon Dec 15, 2014 10:37 pm

Lochiell wrote:Nah I meant "fit" more like just bolting on rather than "fitment" or "stance", I'm not too worried about having my wheels poke out from guards haha I wanna try keep it looking legal as I can..

15x8 +0 is not for you then.

Lochiell · Postby **Lochiell** » Tue Dec 16, 2014 6:59 am

Thanks for your help guys! Makes alot more sense to me now
Appreciate it!
Now I just have to work out some tires for 15x7s

hks_kansei · Postby **hks_kansei** » Tue Dec 16, 2014 9:36 am

195/50/15 is the standard sizing, which gives a total rolling diameter of 576mm

205/50/15 is in my opinion, a perfect fit for a 7inch wheel, it's rolling diameter is 586mm, or 1.7% larger.

That means a 205/50/15 will cause the speedo to read 1.7% under
(ie: if your car does exactly 100kph when the speedo reads 100kph, with a 205 you'll be doing 102kph when the speedo reads 100kph)
My speedo always read about 2-3kph lower anyway (100 on the speedo was actually 97ish) so in my case the size difference took up the speedo error.

Tyre width choice really depends on how legal you want it to be, the rules of which are difference in each state.
Also the tyre manufacturers provide a listing of what width tyres are safe to use on what width rim (ie: it will say 205/50 approved for rims from 6inch to 8inch (just plucking figures out here, check the actual sizes))

Lochiell · Postby **Lochiell** » Tue Dec 16, 2014 10:56 pm

Cheers hks!
I was looking at the 205/50 tyres for the 15x7s today however there seems to be more tyre choice for a 16x7.. Would you say the 15 inch or 16 inch is a better ride for a nb?

I'm in nsw I reckon I could maybe end up having a problem if the wheels where sitting past the guards noticeably,
How do your 15x8+25 sit on your nb? Are they close to within the guards or do they poke out a fair bit?

Sorry to hassle ya, you've been a champion haha

project.r.racing · Postby **project.r.racing** » Wed Dec 17, 2014 6:12 pm

205-50-15s are more common than 205-45-16s. not sure where you are looking.

wheels sticking out of the guards are illegal. and with suspension articulation, you tend to ruin tyres or panels in the process.

hks_kansei · Postby **hks_kansei** » Wed Dec 17, 2014 8:01 pm

Lochiell wrote:I'm in nsw I reckon I could maybe end up having a problem if the wheels where sitting past the guards noticeably,
How do your 15x8+25 sit on your nb? Are they close to within the guards or do they poke out a fair bit?

The +25s were pretty much level with the guards, they didn't stick out, nor did they sit in.

Wheels by hks_kansei, on Flickr
Crap pic. but gives you an idea on the way they sat

Lochiell · Postby **Lochiell** » Thu Dec 18, 2014 5:17 pm

Awesome! Cheers for the picture hks That helped me a lot,

I think a 15x7 is right up my alley!
They would still fill the guards out wouldn't they?
I don't want them to sit past the guards but I would like them to sit flush...

I am planning on getting some ysr/bc or mca coilovers.. This won't affect the wheel fitting will it? I'd think it would help the fit if anything

I know 15x8's are popular but I don't wanna have problems with the cops as I'm young and I'll get farking hassled like no tomorrow if they decide to

Sorry to be a complete rookie with wheels I feel like a time waster haha