Think about it. If foam filled tires were such a great idea every manufacturer would stock them on their mower. I wouldn't even put them on a sid steer loader. Even though you can buy solid tires for a loader I wouldn't want them. Filled tires have more weight on the perimiter of the wheel. So evey time you change speed or direction it puts an extra load on the "transmission" which on a ZTR is a couple of hydraulic motors.