I replaced my original 20" tires with 275/65R20 Cooper At/W's.
These 65 series tires are 10 ply and are heavy but they wear well and are less likely to puncture than the 29lb Bridgestone 60 series SRA's that came on the truck. The original tires were great for fuel economy
I removed the relay and ran 2 wires (male blade connectors at relay) from the underhood fuse relay center then under the driver door weatherstrip to a momentary push button switch.
This works well when it's difficult to get to a dealership