CapriRacer wrote "I just did a quick look and the retail price difference between an ST225/75R15 Load Range D with a wheel and an ST235/80R16 Load Range E, also with a wheel,was about $60.
Does this mean that $300 is the difference between someone buying and not buying a particular vehicle?"
Good point. I'm focused on my own situation at a different size/load point. I'll spot you the wheels and just look at tire prices. Using the first prices I found without digging around, I got:
Towmaster Radial Special Trailer Tire ST235/80R16 (load rating E) @ $160
and
Michelin LT245/75R16 XPS RIB BW E @ $271
The large toyhaulers are triple axle, so 7 tires makes the gap $777. This could raise the msrp by $1k or more. If you made the evaluation of a jump to G load rating with a wheel change the difference gets higher.
