Q: 355 Rear Tire Size...295 vs. 275??

Answers:

1. Yes, 295/35/ZR18s will fit the stock rear wheels quite nicely.
2. No, 295/35/ZR18s will not rub.
3. The speedometer will read 0.8% too fast with 295/35/ZR18s compared to stock.

A very useful tool: http://www.miata.net/garage/tirecalc.html

 

I think I saw gothspeed running 295's with 25mm spacers and it looked too wide to me, but he liked it. The tire remained under the wheel arch, but I thought too much of the tire was exposed along the rear quarter panel. I thought that with narrower spacers it might look better (like 15's). There are a whole lot more tire choices once you move beyond the stock size too. Remember that the speedo error results to odo error too, so too fast means more miles added - basically that's 1 additional mile for every 112 you travel in the example below (big deal ).

However, you should realize that not all tires are made the same with respect to diameters vrs. size, so you need to measure the specific brand you are interested in.

 

I, and a couple friends are running the 275/40/18 size. It works fine, and it is much easier to find than the stock 265/40/18. I doubt any of the tire sizes will make any detectable difference in speedo error. The speedo may read very slightly slower with a 275, but since it is already optimistic in the first place (by 5 to 7 mph) it is probably making it more accurate! Going smaller diameter (and wider width) will only make the error worse, but hardly worth mentioning.

Note that the much larger 295 is going to increase understeer a bit. Looks cool from behind though!

 

I'm also running 275/40ZR18s (Bridgestone S-03 Pole Position) with no problems, and I agree with f355spider that they probably make the speedometer more accurate than stock. They may slightly improve gas mileage too!

 

Try using Tirerack.com, theres alot of good tools on that site for choosing and comparing tires. They give you all of those diameters for all of the different sizes and types. Their prices are usually pretty good too.

CMJ

 

I have 295s and they fit great. Check them in my proflile.

 

I have a pair P275/35/18 Pirelli for sale if interested. they have about 50 miles on them, tits [ no pun intended ] still on tires. 250 bucks. PM me if ya want em. Im in NJ.

 

I would buy them, but I never heard of Perelli----I would rather have Pirelli

 

damn it, thats what i said.

where ya been.

 

i just bought Pirelli P Neros - stock sizes -and they are great.

 

..... Vince... Here is what I am actually running..... ...........stock wheels...... 285/35-18 ps2 with 15mm 355 specific hill eng. spacers..... and it looks perfect.... !!!

 

For the last several years I have been running 275/35x18 Rears. I find the car turns in a lot easier with the 275/35 versus the 275/40 or the stock size of 265/40.

 

BTW if anyone needs non-355 specific 15mm hill spacers... I have two pairs with the proper bolts for cheap!!! PM me if interested .....

 

If you switch from the factory 265/40 to the 295/35 what do you do to the fronts to maintain balance???

 

Keep stock

 

+1
The front stock rim is only 7.5 inches wide so you don't have a choice, you have to run the stock tire size of 225x40.

 

Not much, perhaps add a front spacer? That is the reason why a stuck with a 275, rather than go to a 295..