A zero-turn mower can be a family-friendly tool because it cuts down on your mowing time. While zero-turn mowers make quick work of lawns on level areas and slight slopes, they should not be used on steeper hillsides. The design and weight balance of the zero-turn mower makes it unsafe for these areas due to the possibility of rollover accidents.
Manufacturers of zero-turn mowers vary in recommendations of the maximum degree of slope for safe mowing, due to the various designs and weights of the machines. For example, Toro brand recommends that no more than 15-degree slope be mowed, while Ariens and Gravely brands advise not to mow on hillsides with over 10 degrees of slope. "Consumer Reports" advises homeowners to use a front steering mower rather than a zero-turn mower on slopes of over 10 degrees.
Determining the Slope
You can measure the degree of the hill accurately by using a slope and pitch indicator, found on some carpenter's levels. As a general comparison, highways are seldom constructed with over 10 degrees of slope, unless they must mount a steep hill, and standing on a 20-degree slope will make it difficult to balance your weight equally on both feet. A hillside of 10 degrees will rise in altitude roughly 20 inches along every 10 feet of length.
Dangers on Hillsides
Zero-turns mowers, unlike conventional tractor-style mowers, have only rear wheel steering. The front wheels are only casters and have no power extending to them. The front wheels' ability to swivel freely allows the zero-turn to make its signature sharp turns. If the zero-turn mower is sliding or skidding, as on a hillside, the front wheels cannot be steered. Due to this design, zero-turn mowers can roll over when making even a slight turn on a slope -- even on a low hillside.
When operating your zero-turn on a hill, operate slowly by going up and down, never side-to-side, and only mow when the grass is dry to avoid slipping. If going uphill after a stop, move forward gradually to avoid the machine tipping backwards. If the zero-turn loses control on a hill, disengage your blades and move slowly off the hill. Make sure your seat belt is fastened and the rollover protection system of the mower fully raised and in the locked position. Keep your children and pets out of the area while you are mowing. If a child unexpectedly enters the area, shut off the machine.