Hello everyone, I'm new to this forum and I'm also a new 2016 Mustang owner.
This coming spring I'm looking forward to adding on some some wheels and tires.
I've asked a local shop and they gave me some very rough ideas and didn't really explain much.
I haven't had much luck locating the correct information regarding what will fit into a 20" staggered setup.
My friend has offer to sell me a set of tires he has for a very good price so I'm leaning towards those and they measure in Front 255/30r20 and
Rear 285/30r20.
I'm new to all this but certainly excited to learn from any information you could all provide me with.
Thank you!

 

The factory optional 20" wheels for the S550 Mustang come with 265/35-20 tires. NOTE: Regardless of the wheel diameter offered on the Mustang the tires are sized to keep the same overall diameter except for the GT with Performance Package which has a rear tire that is about a 1/2" taller.

The fronts you mention are a little over 1" shorter in diameter than the tires you have now on the car. They will result in more tire to wheel well gap. The backs are about a 1/2" shorter and will require a rim with at least a 10" width.

 

You need to put your stock tire/wheel size in the app on this site. Then you can compare any other tire/wheel setup to see if what effect they will have.
https://tiresize.com/calculator/ Additionally, the stock non PP wheels/tires have a 27.3" diameter. The closer you stay to that the less you affect the car's speedometer and gas mileage.

 

Thank you guys I much appreciate the feed back.
I'm not quite sure I understand, my stocks are quite small as I have a v6 with the basic wheel package because regardless I was upgrading.
I've seen wheels as big as 315/35r20 on these cars on rear of course and 275 in the front.
Is this just a matter of diameter and not also width as long as it doesn't stick fast the fender?

 

Steven, The diameter of the tire will affect the cars performance. If you stick to tires that are close to the diameter of the stock tire you'll have an accurate speedometer and shouldn't
hurt gas mileage. if you go smaller you'll get less mileage and the car will also be slower not to mention the Speedometer being off. Some guys don't have a problem with larger tires because they have rear gears like 3:73 or more and they also have the HP to turn those heavier tires (drag racers). Of course there is the matter of fitting under the wheel well and that limits the width. But the real reason guys go with such large tires is the width of the tire. Those 315, or 335s are much wider that stock and offer more grip. SO if you don't need the larger footprint for racing the smaller size tires are better for Mileage, and cost.

But if its a specific look you are after then by all means put whatever you can fit on there.

 

The issue is that the 35 in the 315/35r20 is a ratio, not an absolute number. It represents what percentage of the width measurement (in this case 315 mm) is the height of the tire from rim to tread.

That means that the tire you referenced would have a larger overall diameter (or height from road to top of tire) than a tire that was 275/35r20. The width and aspect ratio aren't terribly important as long as the overall diameter or the tire stays the same. That's why Roadk9 direct you to a site that would show you which width/aspect ratios would be compatible with your car.

You feed in what your car came with and then put in the ones you are considering and it lets you know how much different they are.