bmartin8732

what is your factory tire size?

Nuke

Go on tirerack.com and use their search info and survey data to help you decide. Cheap can get you moderately satisfactory performance if you're not driving aggressively.

MustangFirstCar

There are alot of ways to compare tire sizes. Basically you want the overall diameter to be about the same. If you get it close enough, you do not need a re-tune. You can compare using an online tool such as this one

Please do not buy a cheap tire, you will regret it big time. You can check out these tires which are very good tires, but they will wear fast with that 220 rating. Do you have the wheels already or can you get 18x10s or 10.5s? Honestly the increase between 235s and 255s won't be much, and even less if you get the el-cheapo-loco tires from the local junkyard. If I were you I would get 18x10s and fit NT05s on them. Think of it this way. You can spend 700 bucks on ok tires and not enjoy them, or 1000 dollars on nice tires and loves the way your car feels.

bmartin8732

ok, if you have factory 16in tires, 215/65/16, then the 255/45/18 tires will be the EXACT same circumference, which means no tuning required. the 235/50/18 are actually a taller tire than your factory tire. spend the money on good tires in the 255/45/18 size and if you want a wider look, there are always spacers.

Warpig12354

Alright, thanks guys. I think I'm going to go with the Nitto NT555 in 255/45/18.

bmartin8732

glad we could help! Now go get some tires and post up some pics!!!!!!!!!!!!!!!

157dB

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

I did the 18x8.5 rim upgrade.
Whats the offset or backspacing on these 18"x8.5" rims you got?
Beware about the rim to caliper clearance issues.
As well as the 'steering stops' you will need.
Also there is no such thing as 'a good cheap tire'. Its an oxymoron.

Note: For vehicles with 16" wheels from the factory:
-installing 17" x 8" wheels, use steering stop 4R3Z-3932-BA
-Installing 18" x 8.5" or 18" x 9.5" wheels, use steering stop 6R3Z-3932-CA

The first pic is of 255/45-18 BFGoodrich G-force KDWIIs on OEM 18"x8.5"
polished rims. I wore those out and went to a BFGoodrich SuperSport 275/40-18.
And yes, you can really stretch a 275 onto a 8.5" wide rim according to BFG...
The second pic is of the marginal caliper mounting bracket clearance
when using these rims on a S197 that has V6 caliper mounting brackets.
The third pic is of the inner tire rubbage you will have without the steering
stops installed.

235/50R18 STOCK
9.251" WIDE
27.251" TALL
85.641" ROUND
740 REVS / MILE

245/50R18
9.645" WIDE
27.645" TALL
86.851" ROUND
729 REVS / MILE

255/45R18
10.039" WIDE
27.035" TALL
84.934" ROUND
746 REVS / MILE

255/40R18
10.039" WIDE
26.031" TALL
81.780" ROUND
774 REVS / MILE

265/40R18
10.433" WIDE
26.346" TALL
82.769" ROUND
765 REVS / MILE

275/40R18
10.826" WIDE
26.661" TALL
83.759" ROUND
756 REVS / MILE

Warpig12354

Wow, thanks for all of the info! Is the rubbing really that much of an issue? Is it alright if I don't get the steering stops?

EDIT: Are these decent tires? http://www.americanmuscle.com/sumito...255-45-18.html

157dB

No steering stops is what I did.
Take no lock to lock turns in the
parking lots and you will be OK
without them.
Beware of the caliper bracket issues...
Test spin by hand the fronts after you
install the rims and before you lower the
front end to be sure of no clearance issues.
Driving down the street is not the time
to find the clearance issues...

As for the summitos, yes decent but not performers.
Cant seem to find the treadwear/traction/temperature
ratings for those tires...
And they look like rock holders.

Warpig12354

Tread rating is 220.