what size tires do i need to maintain overall stock diameter for 17x8.5 and 17x9.5? I dont need anything really wide for the fronts (8.5'' wide) but i want to try to go with the widest tire i can feasibly fit on a 9.5'' wide wheel in the back. if possible, list all the tire sizes i can go with. in case no one knows, where can i find this info from? should i go into discount tire??

btw stock wheels are 16x8 91 Z28 wheels! 245/50/16

thanks

 

Tirerack( The Tire Rack - Your performance experts for tires and wheels ) gives the specs you're looking for for a wide range of tire manuf.The stock height is in the 25.7" to 26.1" range.Hope this helps.

 

On the front 17 x 8.5 the largerst tire you can fit is a 255 45 17. This tire is 26.1" tall. On the rear 17 x 9.5 you can fit up to a 285 40 17 which is 26" tall. I would recomment BFG KDW rubber but that's just my opinion. Which rims are you going with?

 

i am going with 17 inch chrome ZR1's. i am worried about rubbing up front because my 245/50/16 already rub at full lock. is there something more narrow i can fit on a 17x8.5 than 255/45 or is that the most narrow?

thanks for the replies so far

 

Dan,

Everything boils down to section width. The section width of your tire will change depending on the rim width. Your 245 50 16 is 25.7" tall and has a section width of 10.2" presuming you have a 16 x 8" rim. This means that you have 1.1" of tire sticking out on the inside of the rim and 1.1" on the outside of the rim (10.2" - 8"(rim)/ 2). Here are the sizes that will fit on a 17 x 8.5" rim. Note that some tire heights are a little short and may not look right if you lower the car.

225 45 17 25" tall 9.3" section width 0.4" tire inside of rim
235 45 17 25.4" tall 9.5" section width 0.5" tire inside of rim
245 45 17 25.7" tall 9.8" section width 0.65" tire inside of rim
255 45 17 26.1" tall 10" section width 0.75" tire inside of rim

As you can see the 255 45 17 will still have less tire on the inside of the fender (.75") than the 245 50 16 you have on now (1.1").

Hope this helps

 

For 17" wheels, it appears the best fit for the front is 245/45R17 (25.67" OD). For the rear, if you have at least 9.0" wide wheels, put on a 275/40R17, also 25.67" OD. A match made in heaven.

 

I agree on the 245/45/17 front, 275/40/17 rear. They're about as close as you're gonna get to factory height.

 

thanks so much guys!

 

Ive got firehawk wheels that are the same offset as the zr1s. 17x9 and i am running 275/40-17 all the way around with 2" spacers and nothing rubs. And my tires come almost to the lip of the fenderwells just like my stock did.

Seth

 

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

 

http://www.discounttire.com/dtcs/infoTireMath.dos

theres a usefull one, it has the section width, sidewall hight, and even give approximatly how far off your speedo will be

 

ok so what should i use for the rears because im getting a 17x9.5 wheel... i was thinking 285/40/17. is that the widest i can go??

i will get 245/45/17 for the front (17x8.5)

i was thinking firestone firehawk wide oval tires. i know i can get a 35% discount on those (i can get a 35% discount on any firestone/bridgestone product). does anyone recommend any other tires that have better dry traction? this car will not be driven in the snow or the rain (unless i get caught in rain while driving)

 

285 on a 9.5 sounds good, 245's on a 8.5 would also be fine. - You might fit a 295 or 305 on a 9.5 wide wheel, but those sizes are uncommon. 285 should sit square with the wheel and look proper.

 

thanks a lot

i can get two 245/45/17 and two 285/40/17 Firestone Firehawk Wide Oval tires for $460. sweet deal if you ask me

 

285's



i cant wait to get the wheels