I have a B7100HST FWD with turf tires: Rear-29 x 12.00 - 15, Rear-20.5 x 8.0 - 10. I would like to change them with a industrial tire, but I am having trouble finding R3 or R4 tires to fit the stock rims. I do not want to change the rims if I don't have to. Is there a tire combo that will work?