Tyre Size/Rolling Diameter chart here

[BuzzPuppy]

For all who are curious if there were to be changes to upsizing tyres and the like, it cuts down on the calculations by plugging in all the values yourself.

http://www.miata.net/garage/tirecalc.html


For example, the standard Legnum/Galant uses 205/55-R16, and has a diameter of 631.9mm, whereas according to this, upgrading to 17" rims with 215/45-R17 drops diameter down to 625.3mm

 

[naughtika]

maybe that's why my tyre guy decided to put on 205/50r17

I need new tyres.. damn it..

 

[bradc]

215/50/17 is actually a good option too, but most people put on 215/45/17.

225/45/17 is the ideal size imho for 17" tyres, very close to the stock radius, and you can go anywhere from 35 to 45mm offset without any rubbing problems.

 

[naughtika]

even if I have a soft-cock 17x7 rims? hehe

 

[bradc]

with 17x7 the best sizes are 215/45 which is slightly undersized and 215/50 which is slightly oversized.

 

[Guest]

225's will fit on a 7" easy!

 

[SLY-031]

With a 225 on a 7" wheel, you will have sloppy sidewalls. I wouldn't go more than a 215 on a 7".

 

[bradc]

225 on a 7.5" or 8" wheel is the best bet

 

[2000VR-4]

I got 225/40 on my 18x8's +35, should fill the gaurds nicely and they have just a slight stretch and it works out dam near perfect, only .6kph over at 60kph.

 

[Guest]

mine are similar 235/40 on 18x8.5's + 35 a bit streched.

Using a Navman the GPS speed and dash speed are perfect, both are the same.
This is the first car that has acctually been spot on with the speed indication.

 

[bradc]

it wouldn't be with the stock wheels though

I found something similar, with the stock 225/50/16 wheels it would under-read a little bit, but with 235/45/17's on it is perfect.