AlessandroSicari

G'day gents

I am looking for a street/track tyre, can get a good deal on Nitto NT-05's and have read on a lot of tyre tests advising that they are a very good tyre for this purpose

I run stock Cup II wheels, and to date have stuck with Porsche recommended Michelin PS2 255 40/17 rear and 225 45/17 front

Now the NT-05 come in the right size for rear, however the closest they offer to the recommended size is 235 40/17 for the fronts

The 225 45/17 PS2 are 25" overall diameter
The 235 40/18 NT-05 are 24.45" overall diameter

Will the car run well with the Nittos, despite it being AWD and the fronts being 0.55" different overall diameter?

Cheers
Alex

kjr914

I like this tire size calculator:
http://www.miata.net/garage/tirecalc.html

255/40/17 = 78.6" circumference (rear)
225/45/17 = 78.5" circumference (front-orig, 0.1% difference from rear)
235/40/17 = 76.7" circumference (front-possible NT05, 2.4% difference from rear)

The AWD should be less than ~3% mismatched front-rear, so you are in the range. Also, search "AWD tire sizes" here and there are lots of opinions.

AlessandroSicari

Thanks Keith. Is the within ~3% Porsche recommended?

I noticed you have a pseudo 2WD conversation in your sig. What was involved there?

Cheers
Alex

kjr914

I've seen the 3% quoted here many times, but I don't have a definitive link. Perhaps someone here more knowledgeable will speak up.

Pseudo-2WD = it just stopped working... It had ~100kmi on it when it stopped, and instances of dead vicious couplers or snapped drive shafts aren't uncommon. I AX the car and like the ability to rotate it and have no need for AWD for "weather conditions", a term we don't use here in SoCal.... So I'm planning to fully remove it at some point.