Ok guys I'm getting the Nitto-Invos but they don't have the exact sizes that are currently on my car, I'll list what I have below and what size I'm thinking of getting, if anyone can see me having any problems fitting them or anything please let me know:

OEM Front: 225/50 R18 95W
Nitto-Invo: 225/45 R18 91W

OEM Rear: 245/45 R18 96w
Nitto-Invo: 255/45 R18 99W

All the sizes that Nitto have to choose from is listed below if you see a better fit for the rear or front please let me know:


NITTO 225/45 ZR18 91W INVO(T)
NITTO 225/40 ZR18 92W INVO(T)
NITTO 225/40 ZR18 92W REINFORCED NT555(T)
NITTO 235/40 ZR18 91W NT555(T)
NITTO 255/35 ZR18 94W NTINV(T)
NITTO 255/40 ZR18 99W NTINV(T)
NITTO P255/45 ZR18 99W INVO(T)

The two highlighted above are the ones I've chosen.

google a good tire size calculator or find one referenced here somewhere and find the best match for what you are trying to do. If you are going for better performance than the lower profile you picked for the fronts would be the way to go, but the 255/40 would prolly be a better match for the rear with a slightly smaller overall diameter as well. But all in all the difference may be small enough not to matter, either way. The calculator would let you know for sure.

what would I do with the calculator? and in general does a lower profile mean better performance? because I was thinking the opposite?

The calculator will tell you what is the diameter of your current tire and let you know what the diameter the tire you are interested in. Here are a couple I like:

http://www.4lo.com/4LoCalc.htm
http://www.miata.net/garage/tirecalc.

I think if you try them out you'll see what I mean. Lower performance means shorter sidewall. Shorter is basically stiffer so it deflects less than a tall sidewall when cornering, so shorter is more direct handling, more performance. Think low profile = rubber band, and high profile = monster truck tire. Shorter sidewall also means you feel the bumps more tho, so there is a penalty.

I hope this helps, and the half bottle of wine I just had with my turkey doesnt interfere with the reply Cheers!

Hey thanks for the links, the second one with the diagrams helped out, would it be a problem to get the same size tires for the fronts and rears, by that I mean 255/45 R18 99W?? aren't the rear tires wider by an inch? so wouldn't they need to have wider tires or not so?

actually ignore that question above,

Would I have any trouble fitting the rears since the width is 225 and I'm fitting 255? I'll keep the front on 225/45

Those two sizes will probably light up your vdc/slip lights...the diff between them is almost 4%!! I wouldn't recommend it.

^ I agree, I would not recommend those sizes.

When I picked up my 350Z wheels they had 225/45 (OE for Z) on them.
Having the lower profile on the front sucked big time!!

With your rear selection it will be even worse than what I experienced.


FWIW, this the calculator I like.
It charts all the variables at once.

^ thats a keeper, bookmarked for when I need it!!

On the front, just one comment on the size you highlighted. The load bearing index is lower than OEM. Along with the lower profile, it is highly possible that the tire will get damaged with any significant hit. (I learned this the hard way in the past, always wondered by my tires would get sidewall bulges when going over any pothole or dip at any significant rate of speed).

How about 245/45 for the fronts?

Bloody hell, so you guys wouldn't recommend any of the above sizes correct?

I know it sucks but unfortunately, correct.

Nah it's ok I really wanted these tires but I won't go as far as fitting the wrong size tires, I think I'll be going for Michelin PS2's

I have run 225/45/18 front and 245/45/18 rear with no VDC issues, I have an 07 6MT sedan. Personally, the lower 45 profile in the front doesnt look as good as a 50 series though.

Tire choices are a PIA with the G.

What about 18"x8", ET37 on four corners on g35x '07? Will use 225/50/18 tyres all around too.