It is difficult to see from this photo, but the right front wheel is suspended about 30mm above the pavement [img]https://photos.app.goo.gl/WbYHEuAfGkitaFLi6[/img] While the mower is fairly horizontal in this photo, the ground falls away near the front right wheel. There does not appear to be any travel in wheel height of the suspended wheel. Placing about 5kgs over the front right wheel causes it to go to ground and the left rear wheel then lifts by the same 30mm. In other words, no suspension and a rigid frame.
This video shows the problem (ie, most weight being over front wheels) with braking going downhill, even on a Zero Turn mower . They appear to use a front brake that is neither drum or disk?