“When the steering/speed lever is moved, it controls the flow of fluid through the transmission and the rotational speed or the forward/reverse direction of a drive wheel,” Wozniak adds. “Maximum lever movement means maximum fluid flow, which translates into a rapidly turning wheel. If one drive wheel turns more rapidly than the other, the machine moves along a curved path. If both wheels turn at the same speed, the machine follows a straight path. If one wheel stops and the other turns, or if the wheels turn in opposite directions, the mower’s turning ratio is literally zero, hence the name zero-turn.”
Although the basic design of the ZT mower has remained the same, there are some distinct differences, especially in the placement of the cutting deck. Some manufacturers mount the deck in the center, underneath the operator, while others place it in the front, with the operator sitting behind. In the late ’70s, Walker
Mowers, Fort Collins, Colorado, introduced a front cut design, with interchangeable decks.
“The Walker ZTM decks allow the machine to be used for a variety of different functions,” says Tim Cromley, sales and marketing manager for Walker Mowers. “They’re available in different sizes and, depending on the operator’s preference, the clippings can be discharged from the side or the rear. There is also a mulching deck and a number of attachments, like a blade edger or boom sprayer.”
Manufacturers are continuing to explore improvements in the cutting deck area, much to the delight of landscape contractors who have to deal with difficult terrain.
“Here in Florida, most of our jobs are located close to the beach, and the sand and soil we mow over was eating up our decks long before the mower gave out. So we constantly had to replace the decks and also replace the blades a lot more quickly,” Hurlock said. “But the newer machines are being manufactured with a higher quality of materials, so now we’re able to keep our mowers going for close to four years without having to scrap a single one.”
Deck height adjustment is also a key factor if you have multiple products on the same fleet, or if you’re using two mowers on the same property. You obviously want all the grass set at the same height. On a large property where more than one mower is used, a difference of even an eighth of an inch b e t w e e n t h e heighto f - c u t of the d e c k s can ruin the entire look of the lawn. While speed is definitely a plus in getting the job done, what the client wants when you’re finished—no matter how much time it takes—is a perfectly manicured lawn.
Even with two machines that are each set at 4" height-of-cut settings, a problem can arise. Much like purchasing a size 36" x 34" pair of pants from one store that may not fit the same as a 36" x 34" pair from another, a 4" height measurement on one machine isn’t necessarily the same as 4" on another machine. If they’re from different manufacturers, the cutting height can be off by as much as ¼-inch.
“ZTMs do go faster than traditional mowers,” says Wozniak, “but sometimes it can be difficult to cut the grass as accurately if you’re going eight mph than you would if you were only going two mph. Fortunately, newer technologies can fine-tune the mowers to a specific height, not just a specific number, so you’re able to get the same height-of-cut going at faster speeds, even with different mowers. On earlier models, you wouldn’t be able to do that.”
Problems with the hydraulic transmission systems have also been corrected. One of the biggest service issues manufacturers have seen in the past are the multiple leak points from separate wheel pumps and motors, which require fixing hydraulic hoses and fittings. In some cases, there are up to sixteen different connection points, all of which had the potential for some kind of fracture.
“To correct this problem,” explains Ross Hawley, product manager with Exmark Manufacturing, “Exmark developed an integrated hydraulic transmission, combining all of the traditional hydraulic components into a single, integrated drive system, so there’s a lot less maintenance and a lot less downtime.”
One of the biggest changes overall to the entire mower industry is the introduction of a l t e r n a t i v e - f u e l engines. With the increase in fuel efficiency and emission standards, ZT engines have gone from gasoline to diesel and back, while other fuel sources—such as propane and natural gas—are increasing in popularity.
“The size of the engines has improved dramatically,” says Hurlock. “Four years ago, we were using diesel, but now all our ZTs are air-cooled gasoline engines, mostly because of the cost of the fuel. Also, with larger fuel tanks, our crews don’t have to fill up as often, which saves time, or carry an extra gasoline can, which increases safety.”
Sean Dwyer, global product manager at Husqvarna, Charlotte, North Carolina, says their company introduced a propane model which is having a measured amount of success, but the majority of their ZTs are still gasoline powered.
While the mowers themselves are constantly being modified for optimum performance, another area that manufacturers are paying particular attention to is operator comfort. Ergonomics, the science of designing the workplace environment to fit the user, is increasingly becoming part of the design, especially of the seating area. Everything from the seat cushion to the distance from the foot pedal to the spine of the operator is being carefully calculated to provide the worker with optimum comfort.
“Our seat is mounted using 3D isolation,” says Hawley. “The technology reduces accelerations in all 360° of motion leading to less operator fatigue at the end of the work day. The control arms have very thick padding and we’ve paid particular attention to details like where the operator puts his feet, how the seat adjusts—things like that to make the operator’s environment comfortable.”
A comfortable employee is a productive employee. A productive employee means a happy client, and a happy client means a profitable company. What better way to provide all three than with a fleet of zero-turn mowers?