Until recently, manufacturers relied on a trial-and-error system when designing mower decks. “For years we would buy blades, modify them, and test them with our deck designs; there would be many iterations and changes,” says Bob Laurin, research and development manager, Briggs & Stratton Yard Power Products Group. “But blades are expensive, and that isn’t the most efficient and effective way to do things. We’ve moved on to using computer software.”
In fact, many manufacturers are using computer software to analyze air flow and determine where grass could clog or get trapped under the deck, causing inefficiencies and decreasing cut quality. “Right now, we’re really trying to document how we learn,” says Mark Wittak, engineering leader for Consumer Ride-On Value Stream, Ariens. “In the past, we just kept tweaking things. Now we try to do more up-front benchmarking, which is more cost-effective.”
Grasshopper engineers also use computer modeling and design programs, but a new deck design doesn’t start there. The 3-D model is developed concurrently with a fully functioning hand-built deck that undergoes testing and refining until optimum cutting, discharge and overall operating performance is achieved. “Once the design is proven in the field, the computer model is finalized to provide the fabrication consistency required for robotic welding and precision manufacturing,” says Ruthanne Stucky, marketing director, Grasshopper.
According to the manufacturers interviewed, deck performance is about a compromise among cut quality, noise and power consumption. “We use advanced technology first to understand and then develop these interactions,” says Mike Schmidt, product planning manager for commercial products, John Deere. “This allows us to make the best choices to fit targeted customer needs.”
What factors into deck design?
“We start by understanding what problems we are having and in what areas,” Laurin says. “As we develop prototypes, we try to fix those problems. We travel to different parts of the country to try our Ferris mower prototypes. No one can make a deck that’s a perfect fit for all areas, but we want to create one that works very well in all areas.”
Cut quality is the largest factor for all manufacturers, whether it’s through side discharge, mulching capabilities or bagging capabilities. “In side discharge, we are concerned with not just how well it cuts, but how the clippings are dispersed and how the turf lays,” Wittak explains. Manufacturers also pride themselves on harnessing a deck’s natural frequency, which translates to fewer noise emissions and is a sign of extreme durability.
Customer comments and requests, as well as field test experience, are catalysts for new deck designs with all manufacturers. “Our primary goal for our newest deck design was to improve the function and appearance of rear discharge mowing through clipping distribution,” Stucky says. “We wanted to build on the strengths of our DuraMax deck design and advance the safety and production solutions that rear discharge provides.”
“For our latest mulch-on-demand deck, we had to consider the compromises between a side discharge and a mulching deck,” Schmidt says. John Deere examined the differences among blade lift, blade speed, deck clearances, housing shape and depth, discharge locations, and cut angle.
Deck differences
Laurin says Briggs & Stratton has the heaviest spindle available on their larger machines, increasing strength and durability. Ariens also pushes the quality of their spindles, attributing their durability to “a lot of cast iron which makes them really solid so they don’t flex,” Wittak explains. “We also pay a lot of attention to baffling. Fluid likes to go in a straight line, so a nice gentle change is the best way to get stuff out of the deck as cleanly as possible.”
John Deere’s newest deck provides two modes of operation at the flip of a lever: discharge and mulching. This allows the operator to mow in heavy turf areas when discharging is required and mulch when conditions allow for increased safety and healthier turf, Schmidt says.
According to Stucky, the anvil-edged design and reinforcements in the stress zones create maximum strength without excessive weight on Grasshopper mowers. “Our 4X dedicated rear discharge decks are designed to distribute clippings evenly and avoid clumping for the best appearance possible.”
Considerations when purchasing
It’s no secret that landscapers in different areas of the country have different grasses to cut and different climate and turf conditions to contend with. All manufacturers agree proper airflow is the key to getting the best cut in any type of turf. Deck shape and baffling under the deck, as well as shape and speed of the cutting blades all influence air flow. In addition, choosing and using the correct mower blades, in conjuction with other deck considerations, can make or break cut quality.
“A lot of landscapers buy a mower based on durability and how long it will last. For this reason, I like a lot of cast iron because it dampens vibration by nature,” Wittak says. “Deck thickness is another big factor for professional landscapers. I would love to have marketing that explains some of the tools we use to make decks.”
According to Schmidt, landscapers should consider the size of properties they cut, amount of trimming needed, types of grass and tightness of areas to cut. This determines the size and type (side discharge, rear discharge, mulch) of the mower needed. Once the size and type are chosen, look at the fit with the mower. Does it have enough over-hang for trimming? Are the front wheels or castors positioned for the best possible cut quality?
Consider this:
- Faster blade speeds generally mean better cut quality, high noise levels and more power required.
- Deeper decks generally mean larger capacity, better cut quality and more power required.
- High lift blades mean better cut quality, higher noise levels and more power required.
- Heavy gauge decks last longer before they wear through.
- Good reinforcements provide protection against impacts with turf and other objects.
Beyond basic features, landscapers should use equipment before they purchase it. “Use the mower in the areas you plan to mow,” Laurin encourages. “Too often landscapers buy something because they’ve been told it’s a good product, but they’ve never actually used it.” Laurin also stresses comparing a new mower to what you currently use to cut the same area. Just keep in mind any new machine will require some acclimation by the operator.
While it may not seem like science, an important feature of any deck is its serviceability, Stucky says. A deck that is easy to maintain and requires minimal service will serve you better in the long run.
