Tyre size permutations

bigkeeko · Jan 3, 2011

I know theres a search feature and believe me I`ve used it but bear with me.

I`ve just bought a set of Eibach pro kit lowering springs. (I was limited I live in Scotland). According the the blurb it should lower me about 30-35mm.
As it stands the wheels and tyres in the arches look lost (hence the spring purchase).
The stock 245/45/17s I have on work out at 652mm approx. I have an 03 GT.
I reckon even when the cars lowered there`ll still be room for a family of illegal immigrants to hide so I`m considering new wheels.
I`m after 18x9 front and 18x10 or 10.5 rear.
The general recommendation is 265/35/18 for front and 275 or 285/35/18 for rear.
These work out at 643mm and 657mm for the 285.
The front is way smaller and even though the back is a mosquitoes ball hair bigger than stock they wont still fill the gaps and look right.
So,
I`m thinking of upsizing slightly just to fill the arches a bit better and improve the look of the car. I know it affects the speedo slightly etc but I just don`t fancy rubber band tyres on big rims crashing around country roads looking lost in huge arches.

How about 255/45/18 for front and 285/40/18 rear? That works out 687mm and 685mm. That seems workable to me plus it`ll be a bit more comfortable with the bigger sidewall no?. I can adjust my speedo with my tuner anyway.

Anyone ever upsized that can give me any input?
Bottom line is I`m more interested in how it looks than how it handles.

feel free to comment. My heads wrecked looking at wheel tyre combos

OnyxCobra · Jan 4, 2011

If you want it to look right then I would say keep the stock diameter. 255/45-18 and 285/40-18 are going to look like truck tires and be way too big in your wheel well. I think that much profile on 18" wheels would defeat the purpose of going with a larger wheel.

bigkeeko · Jan 4, 2011

OnyxCobra said:
255/45-18 and 285/40-18 are going to look like truck tires

The side wall is only a fifth of an inch bigger. Hardly a truck tyre but I see what you`re saying.

I used this

http://www.miata.net/cgi-bin/tirescgi

OnyxCobra · Jan 4, 2011

Yeah i know it doesn't seem like a lot, a whole profile size increase is notable. Get what you want though man, i was being facetious about the truck tire thing lol.

2slo95fiveoh · Jan 4, 2011

The prokit isn't too drastic of a lowering.. Eibach also makes the Sportline springs which give a significant difference in drop versus the prokit.
If you are worried about the gap between the fender and the tire, increasing the overall diameter of the tire might make it look a little
goofy IMO... older muscle car, yeah, New edge GT, maybe not.... I would go with a 265/35/18 front, 285/35/18 rear..
Here is a rough comparison between Sportlines and ProKit Eibachs....
Sportline springs (Javis car) look especially at the rear tire-to-fender gap

ProKit springs (my car). Ignore the front tires, way too tall of a tire.

bigkeeko · Jan 5, 2011

2slo95fiveoh.

Thanks man, thats the kinda info I was looking for. The new edges have HUGE fenderwells (arches to me, lol) and even the stock wheels look ridiculously small in there. I`ve saw S197s with bigger set ups and was just thinking I don`t want to splash out $1200 on rubber band tyres for rims to find theres still a huge ugly looking gap.