Tires advice

[edogg2018]

I have the base 18 GT with the 235/50R18 tires and am wondering what would be the most cost effective way to upgrade my tires? I don't mind the stock wheels- i've heard 255 is the biggest you can go with them. As a non PP GT I would like to have faster 0-60s.

This is my daily year round car so the tires would need to be driven all the time. Thanks for any advice.

 

[I Bleed Ford Blue]

How wide are your factory wheels? The PP wheels are 9" wide in the front and have 255's stock. Most likely yours are 8.5" wide so generally 255's are about as wide as you can go. Check out tire rack and discount tire and punch in what wheels you have and they will show you what tires they have that will fit your wheels.

 

[edogg2018]

Thanks they are 18 x 8"

 

[I Bleed Ford Blue]

Generally an 8" wide wheel can take a max of about a 245 tire. It all depends on the tire itself, really stiff and/or really short sidewalls need a wider wheel to mount them on. Back when the sn-95's were still new, the popular tire/wheel upgrade was 275/40/17's on a 17x9 wheels. But 20 years ago sidewalls were not as stiff as they are today. Mine has 275/40/19's on 19 x 9.5's factory in the back.

 

[edogg2018]

I just spoke with Tire Rack they said 255/45R18 would be my best option on the factory rims. Thanks for your help.

 

[I Bleed Ford Blue]

For future reference, if your not sure if a tire will fit, take the section width and divide by 25.4 then round to the nearest .5 inch. That should be the recommended wheel width. Most tires will fit that measurement and can range from .5 to 1" plus or minus that for the min and max wheel size. Taller sidewalls generally can range from from 1 to 2" less than the calculated wheel size.

Example the 255/45 18 mentioned above--- 255 divided by 25.4 is 10.04 so the recommended size would be a 10" wide wheel, but since a 45 series tire has a somewhat taller sidewall most likely the manufacturers recommended wheel width is probably 8.5 to 9" add in the +/- .5 to 1" for min/max width and you can see where they say a 255 will fit an 8" wheel. The pirelli P-zero (the same tire that came on PP GT's and PP ecoboost mustangs) in a 255/45 18 has a recommended width of 8.5 with a min of 8" and a max of 9.5"

Just to prove my point, PP GT's come with 255/40 19's on 19x9's in the front and the specs on the exact tire I have is a recommended width of 9" and a minimum of 8.5 and a max of 10" and they have a section width of 10.2" The rears are 275/40 19's on 9.5" wheels and those specs are recommended width 9.5" with a 9" min and a 11" max and a section width of 11.2"

 

[echo7]

I just got some Cooper Zeon RS3-G1's a few weeks ago, 235/55-18 and holy crap are they amazing. I dropped my best stored 0-30 time down to 2.2, just on a regular highway, haven't been able to do some real good testing with them yet. Think i did a 4.8 or 9 0-60 on that run. They can handle full throttle in first gear where as the Pirelli's couldn't. Very soft and sticky tires, but still rated at 50k miles all-season. I somehow got them at $103 a tire, but usually they go for around $118/$125. They also claim they can handle 1G of grip in corners, hence the G1 in the name. I probably sound like a sales rep from cooper, but i'm just that happy with these tires so far, haha. I was thinking of going for some 255/45s as well, but glad i didn't and saved some money.

 

[edogg2018]

Great advice echo7 thanks! Best 0-60 I've gotten in my 18 with the 10 speed is 4.8 so far

 

[echo7]

I run 87 in it too. Would love to put 93 and take it to the track one day! Family life has got me busy for the next decade or so I think.

I've seen that new 10 speed up against a hellcat a few times in a video, was very impressed how it gave it a run for the money!

These are all my "best" times stored in the track apps:

0-30 - 2.2
0-60 - 4.8
0-100 - 11.4

60ft - 2.4
330 - 5.9
1/8 - 8.8 @ 86
1000 - 11.2 @ 99
1/4 - 13.3 @ 109

 

[edogg2018]

I run 87 in it too. Would love to put 93 and take it to the track one day!

I'm surprised you go with 87, the car sales guy told me I can do 87 but I've done nothing but 93 since I got it. 3700 miles so far-
Awesome times.

 

[echo7]

By my math, I've saved about $900 over the last 45k miles using 87. And yeah, it's safe to use 87, the ECU changes the timing and what not based on what it detects you're using. I'll splurge for some 93 once i get my job title changed at work, someday, haha.

 

[Xar]

I don't like running any ethanol in my Mustang - I run 92 VP Racing fuel (93 is not available here in my part of Oregon). I've run it in my 13 and now my 18... There may be a little difference in power, but ethanol actually lowers mpg, supposedly 2-3 mpg running E10... I pay about $4.29 / gal for the 92 VP non-ethanol gas, never had any problems and only when I travel do I have to change gas up - but I look for ethanol free gas along my route, and plan fuel stops accordingly... Although 87 is fine, I prefer paying a little more for gas, especially since I've paid a pretty penny for the car.

 

[echo7]

Here's what i get on the interstate using 87. 10% Ethanol too.

 

[Dwlow09]

I bought 2 sets of general g max as03 on a 2014 and 15 gt and general g max as-05 on our caddy xts. Love em.

 

[BurningRubber]

Here's what i get on the interstate using 87. 10% Ethanol too.

That’s ridiculous! My first fill up was 200 miles until empty. Do you have 3.31 or 3:55 gears?

 

[Prodigy]

So I am not a big fan of the pilots, and am thinking of swapping out. I understand the tire measurements, my question is what is widest before rubbing issues occur. I have a 16 gt pp1 fastback

 

[echo7]

I have the 3.31. 95% of my driving is highway miles. That particular trip was several 100+ mile trips combined. I average about 25.7 with all my other driving.

That’s ridiculous! My first fill up was 200 miles until empty. Do you have 3.31 or 3:55 gears?

 

[BurningRubber]

I have the 3.31. 95% of my driving is highway miles. That particular trip was several 100+ mile trips combined. I average about 25.7 with all my other driving.

Nice. My commute is about 2mi, mostly stop and go, sit and wait.

It’ll be interesting when I DO get all highway miles in, where the MPG ends up.