Speed odometer question w/new tires

[BowCrazy]

I have a F-150 and am going to need tires on it soon and am going with the BFG AT.

My question is if I put over sized tires on it is there some way to re calibrate the speed odometer? I've heard this discussed but never heard a answer.

THANKS

[daniel044]

You can buy one of these calibration tools -

http://www.stage3motorsports.com/742502-2015-F150-Hypertech-Speedometer-Calibration-Tool.html

What i did is download a speed mph app on your phone and when your driving it will show what speed you are actually doing. So if I am driving 65mph I know I am actually doing 70mph. My speedometer is off 5mph.

[Antlers86]

Tagged!

I have 35s on mine and it's 7mph off. I currently try to keep it in mind or just use my speed app on my phone and place it in the dash.

[Pineywoods]

I went from a stock 31.9" tire to a 33" on a F150 and am curious about the same thing.

[Smithwr]

You can buy one of these calibration tools -

http://www.stage3motorsports.com/742502-2015-F150-Hypertech-Speedometer-Calibration-Tool.html

What i did is download a speed mph app on your phone and when your driving it will show what speed you are actually doing. So if I am driving 65mph I know I am actually doing 70mph. My speedometer is off 5mph.

That also helps on the odometer too. Your going 70 miles but only recording 65.

[BowCrazy]

I looked at the Stage 3 Motor device and I think its a bit to rich for my blood.

So I guess that there's nothing that the Ford house could do?

Thanks for sharing.

[Texastaxi]

There's a speedo calculator on Discount Tire's website that'll give you a pretty good estimate of what you can expect the difference to be.

http://www.discounttire.com/learn/tire-size-calculator

Just about every performance programmer has the ability to adjust for tire size.

[dcbrown]

I set my GPS on my dash and I can see the difference ay different speeds.