I'm going to assume your Thomas has the same wheels as was on mine, which are 22.5. You'll need a couple other items to order them. Look at the data tag above the drivers seat, it should tell you the rim width, which I believe are 7.5" and NOT the 8.25" (this is important, it will determine if they will actually fit the wheel depth wise). You're wheels are likely to be "2 Hand Holes" which are the open voids in the rim, you'll find most of them have more than 2 hand holes.
We sell them to our truck customers. We buy them from a company called
Prime Industries in Va Beach, you might be able to get them cheaper directly from these people...