j-d wrote:
Our 31-ft runs very close to its max weight rating. For that reason I went with what I'll call "upgraded" and you call "commercial" tires. The Michelin XPS Rib is one, another is Bridgestone Duravis R250. We chose the R250. Your 21-ft should be much lighter. You STILL need "LT" (Light Truck) tires and the numbers you posted are what you should be getting.
I got ours from Discount Tire and was very pleased with their professionalism and the price.
The Michelin LTX MS/2 is standard from Ford on motorhome chassis, and it's a good tire.
In my opinion, the Firestone TransForce is a very good choice. When I was shopping, it was my top choice, and best price, among the standard tires I'd actually consider running. You CAN find that tire size in off brands around $100 each. Personally, I'd avoid those.
I looked at the XPS Rib and R250, but those are clearly highway-only tires. I wanted at least a little bit of tread for getting into and out of sites - getting stuck and spinning your tires going up a small hill on wet grass is embarrassing. Not to mention occasional winter driving.
I ended up with a set of Bridgestone Duravis R500 HDs and couldn't be happier.