Having weighed my Classic trailer's individual wheels, I found that fully loaded for camping that the tire with the most weight was carrying about 2,080 pounds. That got me thinking that perhaps a spare could be a much thinner tire since the actual weight carried is much less than the main tire rating and would allow one to limp to a tire store without overloading the other inflated tire.
One reads that if the tailer is pulled on three wheels, one might be wise to put two new tires on that side as the solo tire has been overloaded. In our case, the solo tire would be asked to carry over 4,100 pounds versus the 2,680 pound rating of our Michelin LT225/75R16/E LTX M/S2 tires or the 2,540 pound rating of a stock GYM ST225/75R15D.
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC
TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell
2014 31' Classic model 30 twin beds, 50 amp service, 900 watt solar system, Centramatics, Dill TPMS, disc brakes, 16" tires & wheels