Tire Diameter Changes

[Dinosoar]

What are you guys seeing, and/or doing about, changes in tire diameters? The OE size is pretty tall at 27.7" (275/40-19). Most wider tires are bringing shorter tires with a different Revs per Mile. Is it merely an Odometer/Speedometer inaccuracy?

Also, for the 2018 PP1, the rear OE diameter is 27.7", front is 27.1"...I am going to assume the computer uses the driveling and rear tire as it's measure?

Any simple fixes...like Ford will reprogram the ECU? I don't want to buy a tuner for that alone.

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[Angry50]

what size are you going with? it shouldnt be off so much its a big deal. like a 2-3mph difference at 60

 

[NightmareMoon]

I don't really notice anything with 285/35-19s on all corners. Worst case my speedo may be a mph or two optimistic, which probably helps keep the speeding tickets at bay.

if you care, you can correct your speedo with the Forscan app on PC and the right ODBII reader device which speaks with the Ford bus.

 

[Dinosoar]

I don't really notice anything with 285/35-19s on all corners. Worst case my speedo may be a mph or two optimistic, which probably helps keep the speeding tickets at bay.

if you care, you can correct your speedo with the Forscan app on PC and the right ODBII reader device which speaks with the Ford bus.

I am getting 285/39-19s on all four corners as well. I may just deal with the speedo inaccuracy. I don't like the ODO inaccuracy...I think smaller tires will make the care register more mileage than is true.

I'll just blow it off...unless, of course, they offer up a Ford Performance Power Pack with a tune!

Thanks gents.

 

[sd45t2]

I am getting 285/39-19s on all four corners as well. I may just deal with the speedo inaccuracy. I don't like the ODO inaccuracy...I think smaller tires will make the care register more mileage than is true.

I'll just blow it off...unless, of course, they offer up a Ford Performance Power Pack with a tune!

Thanks gents.

From my computation, your tire diameter is 26.9 inches for a 285/35R19 tire. My 2016 Mustang has a tire size of 235/50R18 and that tire diameter is 27.2 inches. I have had some information that all the tire diameters for the 2015 Mustang to present are about 27 inches. If so, it doesn't seem that the speedometer would vary much between them.

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