First off, I'm sure this question has been asked a hundred times before. My next big upgrade to my '14 GT Premium is going to be tires/wheels. I have the factory 19" diameter rims, both rear and front. I want to stay at 19", to stay under my warranty and not interfere with odometer/speedometer. I use my car as a daily driver, but I will occasionally take it to the track. I want the performance from my wheels, and not just purely cosmetic. However, I need something more practical and neutral to everyday driving in rain and all sorts of conditions. I'm looking at the AM black 19" - now my questions are as follows...

Concerning the wheels, I like the staggered look - how will the 8.5" front/10" rear perform on the track? Would I be more suitable getting, say a 9" or wider front, like the Z28/GT500/Hellcat? Will the wider tires affect my speedometer/odometer in any way?

Concerning the tires, what would be an "ideal" dimensions/make of tire for my above stated driving applications?

I do appreciate the help - once again, I know you all are probably tired of answering this question every time it comes through. I'm just trying to make the Mustang community proud

 

If your into the curves and road course, auto cross driving I recomend a squared tire wheel set up.
Staggered wheel set up can cause the car to push in turns!
I went with a 19" x 9.5" rim front and rear!

 

Check out this site for how different tire sizes compare: http://www.rimsntires.com/specspro.jsp


Quick overview from Tirerack.com -

Original Equipment Size 1: 235/50-18
Original Equipment Size 2: 255/40-19
Original Equipment Size 3: 265/35-20

OE1 is 27.3" tall
OE2 is 27.0" tall
OE3 is 27.3" tall

Tire size math is this:

AAA / BB - CC

AAA is the width, in mm
BB is the ratio, or percentage, of width that gives sidewall height
CC is the diameter of the wheel

It looks like your GT is equipped from the factory with the 255/40-19 tires. These are 255mm wide (10") and have a sidewall of 255*0.40=102mm (4") which gives your tire an overall height of 4"+4"+19"=27"

Now, onto the use. Wider tires do not like daily driving. Narrow tires do not like track use. If you like the staggered look, you can get 19x8.5F and 19x10R wheels and put on those 255/40-19 front and 295/35-19 rears and your speedometer would not be affected. You could also go up to 20" wheels, but the ride would be a bit harsher than the 19s. In that case, 255/35-20 and 295/30-20 would fit without changing your speedometer.

 

Enfynet, the Track Pack/Brembo wheels had 255/40-19 but I think the other premium wheels had a 245/45-19. The '14 brochure mentions the GT/CS cars having the 245's and the other ones (FP8 and GT Premium optional) I have seen on Ebay and craigslist had 245/45 IIRC.

I replaced my stock 18's with Brembo wheels and lost another mph. When my speedometer says 60, my gps says 58. It was 1 mph off before the wheel swap. If I put 275/40 on it next time, that should bring it right up. Not sure I want the 275 on it though. I'll cross that bridge when I come to it.

 

I run 275/40 on my Track Pack wheels. Since I have the 3.73's the taller overall diameter helps me out a little with not running out of gear. A little.

By push he means understeer if you didn't know. When the front of your car wants to plow under the road instead of turn.

Running staggered can be tuned back to neutral handling if you are a road course guy with suspension mods though so don't let that deter you if you like the look.

 

^ This.

If I could hug you and kiss you I would. Can I just send you mustang stickers in the mail instead?
This single post answered every single question I had, and was the easiest to understand!

I was contemplating going to 20" wheels/11" rim and 305 tire in the rear. Daily driver/show car if I can get the sponsors

 

Good luck with the sponsors.

 

Mine is currently equipped with Pirelli 245mm (9inch)/45-19s on all 4 corners. What about staying at that same 9 inch diameter for the front wheels, and bumping up to a 10 inch (275mm) rear? Or how would having 275s in both the front and rear affect performance/fitment? I like the staggered look, but if it is more economical (rotation) and performs better to have 275s all the way around...

 

I have the 275 on all four corners. It's a little more contact patch and more grip. If you get a little more tire meaning taller than the stock diameter it help lengthen the gears a little. I have 275/40 which is slightly taller than the 255/40 this equates to making my 3.73 rear end more like a 3.55. This is approximate as I haven't done the math.

 

245/45-19 are 27.7" tall and 9.6" wide
274/40-19 are 27.7" tall and 10.8" wide

Putting 275s all the way around will improve your traction, but possibly hurt your road manners. Wider front tires will follow imperfections in the road more, but will give you better cornering grip.

 

I have a 2011 GT. I run 19x9 255/40 in front, 19x10 285/35 in rear. Same set-up as Boss LS. Mine is daily driver, with 3-4 track days per year. This works perfectly for me, and the mild understeer on the track is fine. I like not having to use a dedicated set of track wheels/tires (I'm cheap and lazy!). I love the staggered look, too. While Justin's information is extensive, I'm not sure the 295/35 19 size for a 19x10 rear is accurate...Ford recommends 285/35 19. Also, very few tire choices available in 295/35 19 - you do want to choose sizes that you know you can buy replacements easily. Good luck! Lots of great choices.

 

X2 to this. Exactly what I did and it's a great combination.

255/40 for the front
285/35 for the rear

19x9 for the front
19x10 for the rear

 

probably an obvious answer but just to make sure I understand this correctly I have factory 18s and if I upgrade to 20inch wheels with 265/35-20 tires I won't throw off my speedo at all due to the overall diameter of the wheel/tire combo being the same?

 

Correct. The website I linked to will tell you how much your speedometer will change between the two sizes.

 

Budget plays a big part in all this too. What important to you? Performance, handling, looks?

The wheels I'm saving for run $3200 for a set. Tires is another $1300 and mount and ballance another $50 or so.

 

This is perfect, clear cut and dry. Thank you. I was getting a little confused with the differences between rim width on AM (8.5,9, or 10in.). So with a 10 inch wide rear rim, I'm fine getting a 285mm (11.22in.) tire? It gets confusing.

The AM rims I am currently looking at go for 149$ each, and although they are made in China, they will work perfectly fine and accommodate my future Brembo upgrade. AS far as tires are concerned, not really sure which to get, summer or all-weather? As I said before, this is my daily driver and I live in south east Texas - not worried about snow, maybe a bit of ice every few years. The only thing I'm really concerned about is rain. Any suggestions? Thanks again.

 

My advice to you is go to tire rack, read the reviews, check the specs for the tires you are considering. They will all have min and max wheel width ratings for each tire. Some brands run a little wide or narrow depending. I run the Michelin Pilot sport A/S+ and have driven them on the tracks here in Europe with a lot of fun. They grip really well dry, wet, and snow on occation. Well worth every penny. I went with them because they were the highest rated performance all season at the time. Now it's the new version the AS3 that are on top for all seasons. There are close 2nd such as the Continental DWS that are great as well for a little less money if you just need an all around tire.

 

I have. It works out to be 3.64 final drive with brembo wheel/tire combo. I use the same size as you for my track set on 9.5 wide rims to help lengthen the gears as well. I think the contact patch is optimal with 9.5 wide rims in 275/40

 

285/35/19 all around...nearly identical to stock diameter, good tire choices in that size, no rubbing.

You'll need a 9.5" wide rim minimum.

 

So I just talked to the guys at AM - I think I'm going with the 255/40 with the 19x8.5 rim on the front and the 285/35 with the 19x10 rim on the back. This seems like the perfect setup for me. Thanks everyone!