Cool Contractor

Hi all, I did a search and couldn't find an answer to this question. I am looking into getting (4) Ford Racing GT500 wheels which are 19" x 9" with a 40mm offset. I like the daily driver stock Pirelli PZero Nero A/S 245/45R19 but I want to go wider and still be able to do a 4 wheel tire rotation. The problem is they don't make a 255/40 or a 265/40 so it's either the 245/45's or the 275/40's. The 2 questions I have are, will this tire/wheel combo rub at all up front? I haven't lowered it yet, but I may some day. The second question is will the tires look too wide for the wheel. I am not going racing, just spirited driving and it is a daily driver. If anyone has pictures of this size tire/wheel set up, please post them. Thanks in advance.

Norm Peterson

275/40 tires are OK on 9" wide wheels, but only just (9" is generally the tire mfr minimum recommended width for that size).

I know that there are several folks running 275/40-18 on the GT500 18 x 9.5 x +45mm wheels, but they're a whole inch shorter than your 19's and would have half an inch more clearance everywhere.

If you can post up the wheel size (width and offset) for your existing 245/45-19's I can put up a fairly close comparative plot that'll at least show if the 275/40's on the new wheels will be way outside the space that the 245/45's occupy now.

With respect to future lowering - I'd plan on lowering by half an inch less than what the guys riding on 27" tall tires are lowering by. Note that there are some 20's that are still 27" tall (255/35-20), so don't pay much attention to the wheel diameter.


Norm

jsnyng

You will be fine on stock ride height and should be fine lowered as well. I'm on Steeda Sports, and I'm confident those tires will fit at least on the Steeda Sports. My car originally came with 245/45/19's which are the same height (.02 taller) as 275/40/19's.

Here's pics on stock wheels and lowered:


IMG_0190 by jsnyng, on Flickr


IMG_0196 by jsnyng, on Flickr


IMG_0208 by jsnyng, on Flickr


IMG_0194 by jsnyng, on Flickr

Cool Contractor

My stock wheels are the machined aluminum 19" x 8.5" with a 45mm offset. The new wheels are 19" x 9" with a 40mm offset.

Sam Strano

You'll be fine... I've had 295/30-19's on 19x9 42 and 40 offset without issue. Stock size on a Brembo car is 255/40-19.

Though I don't believe GT500's are 9" wide. I think they are 9.5's.

Norm Peterson

Mostly, the extra width of the 275/40 shows up on the outside (right side in the plots). On 9.5" wheels with the same +40mm offset, the outside will move about half an inch outward everywhere (but the sidewalls will show a little less bulge).


Norm

Cool Contractor

Thank you Norm. Now if I could just see some pictures of this tire/wheel set up either on or off of the car.

Cool Contractor

Thank you Sam. The new Ford Racing GT500 wheels just released are 19" x 9" with 40mm offset front and 19" x 10" with a 51mm offset rear. I am interrested in (4) 19" x 9"s. If I am reading the chart from Norm correctly, the tread on the 275's on 9"s are the same width as the rim. I hate the look of the tire tread wider than the wheel. No rubbing issues with the 275's up front?

Sam Strano

Ok, then I stand corrected on the wheels.

As for rub... I see no issue, but there are NEVER any guarantees with this stuff, you just aren't changing the size that much that I see it as being any sort of issue.

Norm Peterson

Tread width is a rather nebulous qualtity due to the shape of the shoulder - just where do you define it to "stop"?. I actually looked up two or three different 275/40-19's and usd an average. Pirelli P Zero Nero A/S M+S dimensions as posted on Tire Rack actually lists the 275/40 as having a narrower tread than the 245/45-19 (8.7 vs 9.0). But other 275/40's go at least as wide as 9.8". I used 9.25".

Keep in mind that a 9" wide wheel is actually 10" wide when you include the thicknesses of the flanges, meaning that it would take a tread measurement in excess of 10" before it even starts looking wider than a 9" wheel. The plot would show that, but can't give you the 3-D perspective view.


Norm