Hi guys I just recently replace my stock wheel and tires with with a 20" wheel and 33" tires. Do I really have to recalibrate my speedometer? Whats the pros and cons of doing it? If so, is there any brand you guys recommend me using. Thanks in advance everyone!!



2015 XLT Sport, 2.5" F150lifts.com leveling kit, 20x9.5 Fuel D560 Vapor wheels with 33X12.5X20 Lexani tires, Revolver X2 bed cover, Weather tech bug and window deflector, Stubby antenna, 6K HID headlight, Ford thermoplastic floor mat, Tinted front window

 

I think your pretty close to stock tire height still. Shouldn't be off by only 1 or 2 mph. I'd leave it.

 

Looking at a very similar wheel/level setup for my truck. Have you noticed a major difference in performance and gas mileage? What drivetrain and rear end ratio you running?

 

If you have a smart phone you can download a free speedometer app. I use Speed Box. The app will give you your current speed based on GPS and you can compare that to what the truck is telling you.

When I switched (stock 2wd tires and 18s) to 34" tires with 20s my speedometer was off by about 10%, thus affecting my odometer, MPG readout, and transmission (shift points). I bought the Hypertec Speedometer Calibrator ($229) and adjusted it to where my speedometer is accurate now.