360 19" tires size

225/35 ZR19 front
285/35 ZR19 rears

You can also possibly use:

235/30 ZR19 front
295/30 ZR19 rears

However the second grouping might throw your speedo off a bit. So, it's best to check with: http://www.miata.net/garage/tirecalc.html.

Then you can try all the options while knowing exactly what they will do.

 

235/35/19
285/30/19

 

i got these on my car:

Yokohama AVS Sport
245/35/19 Front
295/35/19 Rear

HRE 841R Forged 3 Piece Wheels:
19"x 8.5" Front
19" x 11" Rear

 

According to the tire size calculator, the 295/35/19 rear tire will work but will throw the speed off 1.8%. Thus when speedo reads 60 mph you are actually traveling at 61.1 mph. So, that's not so bad. That's very close to original.

The front tire size of 245/35/19 seems to be ok as well.

So, it appears the sizes that Hubert888 gave are doable.

Don't know if those front tires will rub on hard turns, however.

 

my tires do not rub on any turns

 

I just put on a new set of Pirelli P Zero with HRE 847R:

Front:235/35-19
Rear: 295/30-19

These fit fine even with my car being lowered. No rubbing at all. Just remember that the diameter of the front tire needs to be smaller than the rear otherwise your traction control may engage when its not needed.

 

Ok,

But according to the tire size calculator, the 295/30 19 will at 60 mph indicated actually be 58.4 mph which equates to that tire rotating 2.6% faster than would the stock tire!

So that isn't really too bad either but there is 0.8" less of sidewall with that larger tire. So, the ride might be a bit harsher.

Apparently there are many variables in terms of sizes.

The statement about the traction control is quite interesting.

 

Running 335/35/19f(25.5") with 305/30/19r(26.3") Ideally, the 285/35/19(27.1") would have been better.

I was more so concerned with the ratio between front and rear than I was rolling diameter because of traction control. The sizes I chose had the closest F:R ratio between an OEM 360 and CS setup. Also the 305 was a better fit for an 11" rim.

I changed from 255/30/19f with 355/25/19r which was far from the OEM setup. What's funny is, the 355/25/19(25.9") is shorter than the OEM 360 275/40/18(26.6") and the OEM CS 285/35/19(27.1"). That along with the front 255/30/19(25.3") being taller than the OEM 360(24.8) seemed odd.

To jir591's point, the OEM 360 rear is 1.8" taller than the front and the CS is 1.5" taller where as the 255/355 setup is only .6" taller.

Me thinks the ratios are part of the TC program.

G

*Note - Whenever the driving becomes spirited, TC is turned off anyway

 

Are you planning on lowering the suspension??? if so I would install
235/35/19 - in the front. Be very careful with the height.

I have 235/35/19 and 305/25/20 on the rear. I lowered the car and I am having issues. I am going to a ferrari race shop in the morning and they will review what was done by the another shop.

 

You guys are now putting tractor tires on your rigs!

Pretty soon you'll be paying double road use taxes for those extra wide tires!

RobertM, are not the 25 series like riding a bicycle? Not much sidewall there!

Here's what the tire size calculator yields for the 305/25/20:

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
275/40-18 4.3in 13.3in 26.7in 83.8in 756 0.0% OEM
305/25-20 3.0in 13.0in 26.0in 81.7in 776 -2.5% Replacement

The table is not lining up properly.

 

Typo error .... I'm running 235/35/19f(25.5")

G

 

To each his own, but with the setup that I have (even with the car lowered) the 360 runs very very nice and no issues (no TC problems or fender rubbings). I think if you take tire size to the extreme you could have problems without a lot of additional benefit.

 

The reality of all the percentage is fine, BUT really who cares??? I will NOT be sitting in a F1 car trying to qualify for pole anytime soon. So I TRY to mix form with function. He is a Pic of my car with 19 and 20's
Image Unavailable, Please Login

 

Robert,

Beautiful car.

What are your tire sizes, however?

 

Thanks
my tire sizes are:
235/35/19 & 305/25/20

 

Was your car lowered?

 

yes the car has been lowered and now it is at the race shop getting the fenders rolled as I write this response. : (

 

235/35 and 295/30/19
lowered approx 3/8 fr and 1/4 rear
works great, handles speed bumps, no rubbing and great handling
Image Unavailable, Please Login

 

looks great!!!

 

What brand wheels do you have?

 

Vellano Wheels, they are in Calf. and they make an amazing wheel. I have had HRE on my last car and the lips were always cloudy. Never had a performance issue with them.

Call Blake at Vellano and let him know that Robert with the Red 360 spider in Florida gave you his number. They are a first class group. I would highly recommend the wheels.

Vellano Wheels
Blake
(909) 923-6861