I would inspect the rims. Stamped somewhere in the back side of the rim should be a stamped pressure rating. If it is rated for 110 psi, you will be in good shape to use the same rim with a G rated tire.
I would just keep the newest, best tire for a spare.
2011 351RLTS Eagle, Mor/Ryde suspension & pin box
06 F350 Lariat PSD, SRW, LB, CC, EGR delete kit, 16K DrawTite hitch, Timbrens, TST TPMS
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