Hello, JandT and welcome! I moved your post to its own thread since it had nothing to do with the other new member's intro.
If the tires don't match, I suspect they are not reliable and should be changed to ones that are OEM spec. A tire blowout while towing is something you DO NOT want to experience! Several of our members have had that happen and it causes extensive damage and can result in personal injury to you or others too.
Glad to have you with us!
Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH
2014 F150 Platinum 4x4 3.5L EcoBoost SCrew