Paul & Bob's Excellent Adventure: Hydro Walk-Behinds

Manufacturers and operators have told us all about the differences between hydrostatic and gear-drive walk-behind mowers, but we decided it was time to experience the machines for ourselves.

It was something we had discussed for several months. We’d heard all the claims and documented testimony from manufacturers and contractors about the relative merits and shortcomings of gear-drive and hydrostatic walk-behind mowers. But, we thought, how can we weigh these claims without experiencing the machines first-hand?

So, on an unseasonably cold spring day in May, we set out to discover the truth. Richard Bear, owner of Bearco, a dealer and distributor of power equipment in Strongsville, Ohio, offered us a testing area and two machines to operate. Since Bearco is a Scag dealership we used Scag mowers, but the machine features and differences we were interested in experiencing are fairly generic to hydro- and gear-drive machines across most brands.

We looked at speed, ease of operation, maneuverability and control factors and considered price point and maintenance.

The Maintenance Factor
One of the critical differences between the hydro and the gear-drive machine is in the maintenance costs. The hydros provide productivity advantages, but the cost is greater attention to maintenance.

The heart and soul of the hydro is the two hydraulic pumps. It is critical that operators keep enough oil in the pumps and keep the oil clean and free of debris for maximum productivity and long-term mower health. Bear said he has seen a number of problems created by improper hydro pump maintenance. For example, he explained that the pumps use a mesh filter which is 10 times finer than engine oil filters, but too many contractors use the engine filters to save money. This allows excessive debris to enter the pumps and clog them.

When one pump clogs, it won’t pump as much oil as the other pump, and the mower will end up pulling slightly toward the side of the clogged pump. Bear also noted that many manufacturers have extended the recommended oil change cycle on these units because contractors oftentimes do more harm than good when they change the oil.

- Paul Schrimpf & Bob West

THE GEAR DRIVE. The 48-inch, twin-belt machine we tested featured six speeds - five forward and one reverse. Bear explained in our pre-test instructions that reverse gear in many gear drive mowers is an “iffy” thing.

“You have to lock up the handles, make the shift, unlock the handles and back it up,” noted Bear. “Most operators will simply pull the handles halfway up to release the transmission and physically pull the unit backward.”

Having not operated the machine before, we both immediately noticed how much tension the operators experience when pulling on the drive handles. Bob, who has experience working for a lawn maintenance contractor, expected this strain, but Paul was surprised by how immediately he felt it.

One of the most significant aspects of the gear-drive mower we noticed was its turning capability. Attempting zero-degree radius turns with a gear-drive unit requires that one wheel is not moving while the other wheel continues its forward motion. This forces the stationary wheel into the turf with the weight of the mower pushing it down. We were running the mowers over both dry and relatively soft, damp turf, and, where the ground was wet, we left patches of damaged grass.

We did not run the mowers long enough to experience the belt slippage that has been described to us by contractors, but Bear assured us that slippage can be a considerable factor in wet turf conditions.

THE HYDRO. The hydrostatic machine, for fairest comparison, was also a 48-inch unit. These machines have a hydraulic pump connected to each wheel that drives the wheel motors and makes true zero-turn response possible.

The machine is operated by manipulating pistol grip hand controls which shorten or lengthen the control rod running from each pump up to the handles. Lengthening the rod opens up the pump, allowing more fluid to flow to the wheel motor resulting in greater speed. The longer the rod is, the more open the pump is and the more oil that gets pumped into the wheel motors. This gets the wheels moving faster and, obviously, moves the unit faster.

Rather than having to shift a gear, reverse is achieved by pulling the handles up past neutral on hydrostatic units. This is obviously an easier procedure than with a gear-drive unit; plus, by pulling the handles in this manner, the mower’s wheels actually drive the unit backward so the operator doesn’t have to pull the machine. The reverse capability was particularly valuable getting the unit into tight places, which would be an obvious advantage for tricky properties. The hydro units also offer the turf-sparing zero-turn action - one wheel spins backward while the other spins forward.

The added maneuverability of the hydro units provide the economies of productivity when compared to the gear-drive unit, but we found this difficult to take advantage of, even after running the machine for a while.

CONCLUSION. Both machines have the potential to provide an excellent cut and were fairly easy to use without much training. However, to truly take advantage of the benefits of the hydro walk-behind requires extensive training and use. Having Bear available to observe our technique and correct our mistakes was a tremendous help, but we wonder how many new mower operators get the same benefit. When an operator knows what he or she is doing, the hydro benefits are real.

What's Best For You?
When it comes to productivity, the primary difference between the gear- and hydrostatic drive units is control. For the addi-tional $900 to $1,000, the user is able to control forward and reverse on the fly and achieve true zero-turning operation with the hydro unit. Operators trained to maximize this advan-tage can enjoy an additional 20 percent in productivity, according to Richard Bear, owner, Bearco, Strongsville, Ohio.

For contractors starting out in the industry, the gear-drive is an excellent machine. Bear described a recent gear-drive purchaser who was buying a machine for his sons to start a lawn maintenance business. “It didn’t make sense to sell him a hydro,” explained Bear. “The gear-drive made perfect sense for what they needed.”

- Paul Schrimpf & Bob West

The authors are Managing Editor & Associate Editor of Lawn & Landscape magazine, respectively

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