Deep in the heart of Florida, miles away from any major metropolis, is the Sebring International Raceway. For 360 days a year, the track is quiet. On those other five days, thousands of people arrive at the raceway for one of the premier events in motorsports, the 12 Hours of Sebring.
The event is a grueling challenge of endurance and focus. The Florida sun beats down on the racers while they navigate the famously bumpy track. The race teams use the event to prepare for the 24 Hours of Le Mans in France, one of the biggest racing events in the world.
Stories from the track are legendary. Mario Andretti and Steve McQueen competed against each other there in 1970, with Andretti’s team finishing first and McQueen’s team finishing second. McQueen showed he wasn’t just tough on screen but also out on the course, completing the race with a broken foot wrapped in a plaster cast. It’s tales like these that show how the 12 Hours of Sebring event has always been a true test of spirit and skill.
But these aren’t the only things being tested at Sebring. The raceway is also home to the AriensCo Product Validation Center (Sebring PVC), where Gravely and Ariens mowers are pushed to their limits for thousands of hours throughout the year. It’s one of four test facilities that the company operates around the world and it consistently provides the one thing you really need to test mowers: lots and lots of grass.
“It’s always warm in Florida and there’s plenty of grass to mow,” said Doug Kortbein, director of AriensCo’s testing operations at Sebring.
Kortbein moved down to Florida from Wisconsin five years ago to run the facility, which sits directly in front of the racetrack. Before joining the company, he worked for Milsco Manufacturing, which produces the seats found on several zero-turn mowers. With a strong background in manufacturing and a deep knowledge of the company’s products, he was a natural choice to manage operations at Sebring.
“After a product is designed and initially validated in Brillion, Wisconsin, we send the mowers down here for two rounds of as much as 1,300 hours of testing,” he said. “We run them across all of the different grass types and look at the cut qualities. If we find any inconsistencies we work with engineering in Brillion to determine how we can improve the design.”
And there are lots of grass species to be found at the Sebring facility. Directly in front of the building that houses the Sebring PVC are 40 acres of grass, all of various species arranged in a grid, complete with trees, ditches and embankments. This enables the mowers to cut through different types of grass and gradients on a single pass. Bermuda, St. Augustine, Bahia grass, Floratam and Empire Zoysia are all represented, each chosen for its unique thickness and growing pattern.
“We get down on our hands and knees to get close to the blades and see how well they’ve been cut. We look for stragglers sticking up from the lawn, and if we see too many that didn’t get cut, or we see a repeating pattern in the cut quality, that gives us a clue as to how we can improve the mower’s design,” Kortbein said.
In addition to the 40 acres of grass species in front of the Sebring PVC, there are approximately 350 acres of lawn to cut in and around the 3.74-mile track, and Gravely mowers are handling those duties as well. And if that wasn’t enough lawn to mow, the team also has access to 1,000 acres of off-site mowing areas to ensure that the mowers are seeing all types of terrain challenges.
These include areas around local highways and hotels, a famous Florida state park, residential developments and airport properties. As they say in Sebring, the grass grows year-round, and Gravely mowers are doing all of the cutting.
“For almost any challenge that our customers run into, we have a place to test mowers so that they can get the best usage possible,” Kortbein said. “We utilize a customer-centric reliability matrix that measures critical data points to ensure we are getting useful results. We even have two machines here that we have tested for more than 7,000 hours to make sure they are holding up to more than three times their design life.”
The rigorous testing at the Sebring PVC yields tremendous benefits. Gravely mowers are run for thousands of hours to test their durability, reliability and design. They’re put through their paces, cutting grass out on the testing fields for some 130 hours per week. Depending on the season, up to 21 people are working at the facility, which includes an extensive demonstration area and a full working shop.
“Back in this shop is where a lot of the action happens,” Kortbein said. “Real design changes result from the tests that occur here. Issues out on the test lawns often signal an opportunity for improvement by working closely with the engineering group.”
CBT (Constant Belt Tensioning), for example, came directly from testing done at the Sebring PVC. While putting a Gravely mower through its paces on grass heights over one foot, Kortbein and his team noticed a pattern of stragglers occurring at regular intervals on the lawn. They first realized that the mower’s engine wasn’t delivering full power to the blades, and then learned that there was slippage in the belt over one pulley that spun the blade. So a fix had to be engineered.
That fix, CBT, ensures that a mower’s belt tension is constant, minimizing wearand heat while providing enhanced belt life without the need for adjustments. It produces a consistent blade tip speed, eliminates slippage, improves engine efficiency, saves fuel and ensures consistent cut quality.
“We redesigned the belt system so that more of the belt was pulled across the pulley,” he explained. “This increased surface area of the belt along the pulley and gave the spindle more torque and eliminated the slippage. With no slippage, the engine was able to deliver its full power.
From then on, we didn’t see any more stragglers on the testing field.” This feature has been rolled out across the Gravely mower range, setting a new industry standard. It’s just one of the dozens of improvements and enhancements that have resulted from testing at Sebring.
The Pro-QXT Brush Mower also saw its design greatly improved at the facility. After the concept was conceived back in Brillion, the attachment was fully validated through four full generations of the product’s prototype phase. Sebring PVC, working closely with engineering, including CAD modeling, data analysis and plenty of on-site testing, helped produce a light yet powerful cutter that utilizes Gravely’s quick-attach system that enables a single operator to easily transition among attachments.
“There is a really strong connection between Brillion and Sebring,” Kortbein said. “We transmit a lot of design and engineering ideas back and forth so that our products can be directly influenced by the valuable information that comes from real-world testing.”
Earlier this year, members of the Gravely Ambassador team visited Sebring to see the facilities firsthand and share their experiences on social media. They were able to check out several of the newest mowers and Atlas JSVs (job site vehicles) and get a peek behind the scenes at some models that have yet to hit the market.
One of those was the much-anticipated Gravely EVZT prototype. The mower sits in stark contrast to the loud cars that are often tested at Sebring — it’s so quiet, the ambassadors didn’t realize the machine was even on. The AriensCo product validation team is now putting the battery-powered mower’s individual components through extreme testing to ensure the quality and the durability of the finalized machine will live up to the hype.
“A product can only be as good as the sum of its parts, so the Ariens validation team is really examining and scrutinizing the components that make up the EVZT so that we can be sure it is as reliable and durable in the field as our other mowers,” Kortbein said. “There’s nothing more fulfilling than finding a problem and making sure that it’s fixed so that no customer ever has to deal with it.”
The Gravely Ambassadors took to the Sebring testing lawns themselves, trying out a number of mowers and Atlas JSVs on the various species of grass, as they climbed up and down embankments, whipped around trees and practiced their maneuvering skills. It was a great opportunity to see how much testing and design-engineering is applied to every piece of Gravely equipment on the market.
In the distance, racecar drivers were putting a couple of custom-painted Ford Mustangs through a series of tests on a concrete track. In essence, the Ambassadors’ and the drivers’ tasks weren’t all that different. They all wanted to see what their machines could do.