Hello all, I have a 2014 F250 SD CC XLT 4x4 with the 6.2L and 3.73 gears (4.30 upgrade coming, soon as I can work out warranty issues) running 245-75R17 tires on 17' rims. My friend bought after market rims for his 2012 Lariat and I can get his stock 20's cheap. If I install these, will I notice any lack of power? His truck is the diesel but the 6.2 powered lariat is available with the 20' rims. Is there any thing different programmed into the computer on the gas trucks to handle the bigger wheels? Additionally, tirerack.com claims my speedo will be reading over 6 mph too low, how hard is this to correct? Thanks for any info.

 

As long as the tire size and axle gear combination was available together from the factory your dealer can change the computer settings to correct speedo issues.

 

6 mph off seems like a little much. I have the same combo (245/75r17) and I'm pretty sure my speedometer shows I'm going 2-3 mph faster than I really am.

I'm thinking when I get bigger tires the speedometer will actually be more accurate.

 

Easy change at the dealership or with a tuner. No significant performance change.

 

Cool, thanks for the info. There is a speed/performance shop in town, I'll see if they can recalibrate the speedometer. These wheels did seem to raise the truck about 2".

 

Just for grins, maybe you could take it out on the highway with a GPS and compare your speedo to what the GPS is giving you for MPH.

 

Yep... you can't get much more accurate than that!!!

Jim D