tire help

[94svtcobra]

wat size tires should I get for a set of 18x9 18x10?

[94svtcobra]

any recomendations?

[2001GTTT]

i say fronts 275/40/18 and the rears 315/35/18

[Troll]

i say fronts 275/40/18 and the rears 315/35/18

better make that 275/35/18 front and 315/30/18.

you're gaining an inch of wheel, so you have to reduce the sidewall to get close to the proper total wheel/tire height.

I hate giving this lesson. 1 inch = aprox 25.4mm. 17" wheel x 25.4 = 431.8
The second number on your tire is the percentage of tread width that your sidewall is in height. for example 245/45/17 tire or 275/40/17 or 315/35/17
245 x 45% = 110.25mm / 275 x 40% = 110mm / 315 x 35% = 110.25mm

So take 431.8 (height of 17" wheel in mm) + 220.5 (110.25+110.25 because you have to add sidewall for top and bottom) and you get approx 652mm total wheel/tire height.

So, take an 18" wheel (18" x 25.4 = approx 457). Take the aforementioned total wheel/tire height of the 17" package of 652 and subract the new wheel size of 457 = 195mm. This is the total tire sidewall you can have. Divide by 2 for top and bottom and you get 97.5.

You have to find/use a tire that calculates to 97.5mm on the sidewall to keep your stock wheel/tire height.

So 275 x 35 = 96.25 and 315 x 30 = 94.5

That's about as close as you're going to get. You can mess around with combos for 265/35 (92.75) and/or 305/30 (91.5) or anything else you can imagine.

[u1arunit]

better make that 275/35/18 front and 315/30/18.

Exactly! That is the combo that I run for street use.

Here are links to a couple tire size calculators:

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

http://www.1010tires.com/TireSizeCalculator.asp

http://ejelta.com/tiresize/index.html

[biminiLX]

These would save you some money on the fronts :)
http://www.steelcitystangs.com/forum...ead.php?t=8042

I'd recommend 305/35/18 Nitto DRs if you're making decent power and want to run on a DR.
-J

[2001GTTT]

:o oops.....sorry.