Hustler(R) Turf Equipment (Hesston, KS, U.S.) decided to improve upon the concept of the zero-turn radius mower with its ATZ(TM) model. According to Adam Mullet, product manager for the company, one of the biggest problems with zero-turns occurs when mowing on a slope. In this situation, he says, the weight of the mower shifts to the front wheels and the rear wheels - the drive wheels - which don't have traction. "Once you start sliding in a zero-turn, you're going to hit the bottom," Mr. Mullet says.
To conquer this problem, Hustler modified one of its Super Z(TM) mowers. First, engineers extended the length of the mower by 12 to 87 in, and increased the width to 59 in. Mr. Mullet says this change helps to limit the percentage of weight imbalance when the mower sits at an angle.
In order to increase traction, the company also made improvements to the wheels and tires of the Super Z. Instead of the turf-tread tires from the Super Z, the ATZ features a bar-tread design that faces backwards. "This is because going uphill or traversing a hill is no problem," says Mr. Mullet. "The main aspect is when the user turns the mower down. We wanted the traction facing the back of the tractor." The company also added 50-lb wheel weights in each wheel well and close to 180 lb mounted on the frame between the wheels to place more weight on the drive wheels. According to Mr. Mullet, the improvements allow the ATZ to back up a 25-degree slope when the slope performance of most zero-turns is 15 degrees.
Other features include the option for a 60- or 72-in deck, a 12.2-gal fuel tank, a top speed of 9 mph with a 27-hp Kohler V-twin engine, and a 6-post ROPS (roll cage). "We did this [the roll cage] mainly because it makes the operator feel more comfortable," says Mr. Mullet. "We wanted this to be a slope mower, and we wanted the operator to feel secure."
The wheel motors for the zero-turn drive system are CE 24s that reportedly provide more torque at lower pressures for improved slope performance. "If you're working on a hillside, it puts a lot more pressure on your hydraulics than on flat ground, so [the wheel motor] enables users to handle it better."