[K-TRON]

Tom,
Have you ever thought about adding dual wheels to rear of your garden tractor? I have driven more modern Ventrac 4100 and 4200's with duals and they are incredible on slopes. I am not sure which mower you have, but I am sure that you can adapt at least one side in the rear to run dual wheels. You would have far more stability and traction then with a tire which is just 2" wider. In fact the tire will not even be 2" wider, because the rim size is going to stay the same. The tire may only be 1" wider on the same rim!

Chris

 

[K-TRON]

Tom,
Check here:
Lawn/Garden Tires - m. e. MILLER tire

Miller tire has a very good selection of tires, and even lists outside diameters and overall widths of each individual tire they sell on the rim that they are designed to fit. I hope that helps some in your search. Judging by the size tire you list, you also should be able to find rim mounted weights which you can add. Even if you can bolt on a 30lb slug of steel to each rear rim, I think that your mowing experience will be much better!

Chris