2015 Mustang Ecoboost K/SA?

6130 · 06-16-2018, 02:33 PM

Okay, Alan, let me bounce this off of you, regarding tires, wheels, and gearing.

The Ecoboost Mustang won't take anything smaller than 17" wheels over the stock front and rear brakes (18" in front, if it's a Performance Package car).

The 6R80 cars have 3.31 rear gears (Performance Package 6R80 cars get 3.55 rear gears). 4th gear in the 6R80 is 1.14, and the stock tires are 27" tall. Ford says the horsepower peak is at 5,500 rpm. 110 mph through the lights with 3.31 rear gears, a 1.14 4th gear, and a 27" tall rear tire, is just a little over 5,000 rpm (just about 5,500 rpm for Performance Package 6R80 cars).

I'd want to keep the front tires the same height as the rear, to avoid any problems with the ABS system (don't want to smoke the tires in the lights). I wouldn't want to go any shorter than the stock 27" tires, because I wouldn't want to lose any roll-out in the front. And I wouldn't want to go any taller than 27", because I wouldn't want to lose any torque multiplication or put the engine further from it's power peak through the lights, nor would I want to have to change out the ring & pinion to offset for taller tires.

NHRA says no more than 9" tread width in the rear, and no less than 4.5" in the front.

I'd like to avoid putting radials on one end and bias-ply on the other.

And if I was going to try to save the expense of a truck and trailer, I'd want the tires to be DOT-legal. That would also save me the trouble of having to change them at the track.

I don't think the wheels would need to be anything fancy- again, it looks like these cars will run under without a lot of work. For example, there are Race Star wheels available in 17x10" and 17x4.5" sizes.

What are your thoughts on tires and wheels for this purpose?

06-16-2018, 02:33 PM	#11
6130 Member Join Date: Jul 2012 Location: Texas Posts: 409 Likes: 295 Liked 117 Times in 50 Posts	Re: 2015 Mustang Ecoboost K/SA? Okay, Alan, let me bounce this off of you, regarding tires, wheels, and gearing. The Ecoboost Mustang won't take anything smaller than 17" wheels over the stock front and rear brakes (18" in front, if it's a Performance Package car). The 6R80 cars have 3.31 rear gears (Performance Package 6R80 cars get 3.55 rear gears). 4th gear in the 6R80 is 1.14, and the stock tires are 27" tall. Ford says the horsepower peak is at 5,500 rpm. 110 mph through the lights with 3.31 rear gears, a 1.14 4th gear, and a 27" tall rear tire, is just a little over 5,000 rpm (just about 5,500 rpm for Performance Package 6R80 cars). I'd want to keep the front tires the same height as the rear, to avoid any problems with the ABS system (don't want to smoke the tires in the lights). I wouldn't want to go any shorter than the stock 27" tires, because I wouldn't want to lose any roll-out in the front. And I wouldn't want to go any taller than 27", because I wouldn't want to lose any torque multiplication or put the engine further from it's power peak through the lights, nor would I want to have to change out the ring & pinion to offset for taller tires. NHRA says no more than 9" tread width in the rear, and no less than 4.5" in the front. I'd like to avoid putting radials on one end and bias-ply on the other. And if I was going to try to save the expense of a truck and trailer, I'd want the tires to be DOT-legal. That would also save me the trouble of having to change them at the track. I don't think the wheels would need to be anything fancy- again, it looks like these cars will run under without a lot of work. For example, there are Race Star wheels available in 17x10" and 17x4.5" sizes. What are your thoughts on tires and wheels for this purpose?