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My NB8A has its stock 15inch wheels which I am not a fan of.

Is there any reason to go with 16inch wheels instead of 15?

Also I'd like to have some more offset as I think wider wheels suit the look of the Mx5.

What is a good offset that is legal and maintains the driving characteristics? (My car is stock height)

Any wheel recommendations are welcome.

From a legal perspective 33.5mm offset is the most you can do. 25mm of changing track width so 12.5 each side

Going 16 or staying ar 15 is a personal choice.
15 inch will give you more options as well as cheaper options

Just my experience .......

I had aftermarket 16x7's with 205/45-16 Yokohamas on my NB8A and they weighed as much as 15x8 steelies, both with tyres. Looked good and wide though and filled the wheel wells on stock height suspension.

I have swapped to stock 15x6's with 195/50-15's. They are a lot lighter giving better handling and ride, and are not as hard to launch. If I had a 4.3 rear diff that would have made the 16x7's liveable.

One day I hope to fit 15x8 6UL's because they are light enough to go that wide.

Might go with 15 x 6.5 then

15x7 +35 offset are a nice fit on a NB. I fitted 205/50/15 tires and very happy with the way they sit in the guards.

Snowmotion wrote:15x7 +35 offset are a nice fit on a NB. I fitted 205/50/15 tires and very happy with the way they sit in the guards.

have you got any pics?

on a legal point I think you can add 1 inch to the width of the car without having to get an engineer to change the place-card. Having said that. I don't think if you go a fraction over doesn't mean you are going to get picked up by the boys in blue.
I think the the standard factory recommendation for NB8A is 6.5 so theoretically you can go all the way to 7.5 inch width. However check that on your tyre card on the doors. I'm not 100% sure
That's stickily legally talking. A lot of people just ignore this.

StanTheMan wrote:on a legal point I think you can add 1 inch to the width of the car without having to get an engineer to change the place-card. Having said that. I don't think if you go a fraction over doesn't mean you are going to get picked up by the boys in blue.

The 1 inch is on Total track width. Not per side. It also depends on the offset so in theory you can fit 9 inch wide wheels if the offset is right.

Snowmotion wrote:The 1 inch is on Total track width. Not per side. It also depends on the offset so in theory you can fit 9 inch wide wheels if the offset is right.

You cant legally go 9" rims in Victoria.
Not sure what state OP is, but in Vic you can only go 1" wider in rim width, and (as Snow & STM said. 1" in track width so 12.5mm offset increase per side (Std +45 to +32.5).

{quote from Vicroads VSI8]
"The width of any replacement rim must not be more than 25mm greater than the widest wheel specified by the vehicle manufacturer for that model or series"

"The maximum allowable track increase is in the case of a front axle 25mm, in the case of a rear axle with independant suspension 25mm"
[endquote]

Snowmotion wrote:

StanTheMan wrote:on a legal point I think you can add 1 inch to the width of the car without having to get an engineer to change the place-card. Having said that. I don't think if you go a fraction over doesn't mean you are going to get picked up by the boys in blue.

The 1 inch is on Total track width. Not per side. It also depends on the offset so in theory you can fit 9 inch wide wheels if the offset is right.

apologies I wasn't clear I was talking width of the rim. Track width has already been covered. width of rim is a separate issue to track width the way I understand it.
It may also vary from state to state.

Track width is measured from the center of the rim. Not the outside of the rim.

In NSW, the way I read it is:
- total track increase is 25mm absolute
- wheel rim width increase is 26mm, but may be able to go wider with engineering

http://www.rms.nsw.gov.au/documents/roa ... 9-rev4.pdf

That link is probably too long to work, so google "vsi 9"

pretty sure standard nb8a offset is 40mm.I have some wheels in the shed will check later,
Mick

noobee wrote:pretty sure standard nb8a offset is 40mm.I have some wheels in the shed will check later,
Mick

I think you may be right... so +27.5 (40 -12.5) is max legal offset.

yep,just went and checked stock nb8a wheels. 15x6jj40.
Mick

noobee wrote:yep,just went and checked stock nb8a wheels. 15x6jj40.
Mick

For reference;
- standard NB8b/c are 16x6.5 +40
- NB SE are 17x7 +40

So using the 'largest size fitted rule' the maximun leagal numbers you can go for are;
- up to 8" rim width
- up to +27.5 offset

That being said the most popular fitment is normally;
- 15" rim diameter
- 7" to 8" rim width
- +32 to +38 offset