Greg107

I have a 2016 FX4 with the OEM 20" five spoke wheels and Hankook 275/55/20 Tires. Its time to replace the tires and to me they look a little small. I would like to look at putting on a taller tire to fill the wheel well a bit more. Not looking to go any wider on the tire and would not have a leveling kit.

Any suggestions on what size tire I could go with and possibly not have to have the speedometer recalibrated? Also any suggestions on a tire? I am in Montana and drive 80% pavement and 20% gravel roads. Also live up in the mountains and need a decent tire for snow .

Thank you

Greg

ghunt81

You can't go taller and not have to recalibrate the speedo. Anyway, 275/60R20 is a 33" tire and 275/65R20 is a 34" tire.

tenx82

With a 275/60R20, the speedometer will read about 3% low. So when it says 30mph, you're actually going 31mph; at 60mph you're actually going 62mph.

A large number of people find this acceptable since no speedo is 100% accurate anyway.

bobn

Greg107

If I go up one size in tire height do I also have to replace the spare tire? If I get a flat, the spare would be smaller. Also do I have to make do anything to the Ford Navigation system to keep it accurate?

Thank you

Grg

GMC to Ford

275/60R20 and LT285/5520 are considered +1 tires. I believe the specification from Ford is that the tire size has to be within 4.1% to avoid any issues with the 4WD drive system and transmission shift points. Someone correct if that number is high. Both tires fit the +1 requirement. The factory spare will work as long as you do not engage 4WD and replace the original tire quickly. It can affect your 4A system performance (i.e. traction control) if you have it.