Most people buying new trucks just accept the tires come with the truck; wear them out and then purchase the tires they really need. Remember, long term it’s the wheels you are most interested in. On the back of the rim is stamped the load rating of the wheels, whih you can find by lowering the spare tire enough to see the inside rim. My choice was always a higher load rating than bling. Sometimes….you can negotiate brand new ‘take offs’ which are tires/wheels someone else did not want at the dealer. With the “AT” designation, they are likely All Terrain tires which are universally light duty mud and snow rated if they have enough sipes. Overall, 18 inch tires/wheels are a good bet as they can be had, aftermarket, in a high load rating: higher than 17’s and a larger selection of high load rated tires.
2020 Ford F-350 XLT FX4 4WD SRW SB SC 7.3L Godzilla Gas TorqShift 10R140 397 amps dual Alt dual batts Frnt Dana 60; Rr Dana M275 E-locker 4.30's 4580/4320/4066# payload 7243# curb wt. 11,300# GVWR 5-er prepped. 2020 Northstar Laredo SC, 12v compressor fridge, cassette, 320w Solar sub zero insulation.