The weakness of the Gravely with an oversized plow is in tractive effort, which is really a function of the weight on the tires. Notice the backward cant on the car pusher? That's a very clever design, as it uses the weight of the car being pushed to force the Gravely downward. You'd actually have to push down on the handlebars a bit, but as the load increases, so does your tractive effort. I remember Caterpillar played around with the blade design and the resulting dynamic forces of the load being pushed, on the D-11's, resulting in the Carrydozer which was more efficient when pushing material over distances.