Could you post a picture of a bad wheel.

There are plastic webs like spokes on a wheel. The gear on the axle grinds these spokes to nothing. I feel the axle has too much play side to side allowing this to occur. I will try to place washers on each side of axle to minimize this movement and see what happens. The wheel is heavy where the gear is mounted and the rest of the wheel is light weight plastic. When the spokes get ground down the wheel cannot handle the weight of the mower and the torque of the axle causing the wheel to fall apart. These wheels cost 30 bucks each and should be of heavier gauge material.

I just replaced a set of wheels like this on an abandoned mower left in my shop. I had a set from an old mower that was at least 20 years old. Surprisingly nothing has changed; they bolted right on.

The only difference is that the mower manufacturers have decided to increase profit margins by making a totally plastic tire.

Hopefully you can find a steel spoked set somewhere and use them.

'Hopefully you can find a steel spoked set somewhere and use them.'

You're not getting it - the axle slides out and the drive gear teeth eat up the wheel just like those cutting blades that came out of James Bond's Aston Martin. If he had steel wheels it would ruin the gear too.
I don't know what the answer is, but I have noticed the axle has a lot of end play on the Variable Speed drive which essentially is the same as PP except with manual control. I guess you'll have to look in the gearbox to see if a C-Clip is missing or broken or what else you may find.

You're right saxman. The description was confusing and took me in another direction.