Nearly every manufacturer of self-propelled high clearance sprayers has recently introduced or is almost ready to introduce a better suspension system.
The reason is simple: better suspension provides a better ride at the higher speeds that high clearance sprayers now travel.
Ride has become a major comparison factor when producers go sprayer shopping, forcing manufacturers to improve their suspensions.
The Miller Nitro 4000 series is the latest to be outfitted with a new suspension.
It has fully independent suspension at each wheel, and each wheel has an unprecedented 20 inches of vertical travel, controlled by its own nitrogen accumulator.
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Tim Criddle, sales manager for Miller, said suspension is not just about improving operator comfort and reducing machine stress.
“Suspension is really as much of a traction device as it is a ride system.
“All of us manufacturers struggle to maintain good weight distribution and equal traction on the ground. Operators seldom spray on a nice smooth field. Most of the time you’re dealing with rough, uneven terrain, mud, ruts and all kinds of factors working against good traction.”
Criddle said uniform weight distribution is an important way to reduce compaction and prevent the sprayer from becoming stuck.
It is also important throughout the full load range, from empty to full. Criddle said an operator has a good chance of dropping into the mud if his sprayer is 50:50 when empty but 65:35 when full.
“If you drop your left rear into a rut, the diagonally opposed tire raises up in the air. Now your left rear is spinning in water and the right front is freewheeling. It lifts right up off the ground.
“There’s lots of complex traction control systems out there supposed to ensure equal flow to all the tires, but the reality of hydrostatic drive is that if you’ve got one wheel spinning free, the oil wants to flow to the wheel with least resistance.”
The left front and right rear tires are now supporting the entire weight of the sprayer. Those are the tires with necessary traction, but they’re not going anywhere.
Criddle said a well engineered suspension can prevent this situation. Long suspension travel at all four corners allows the left rear to dig down a little deeper while the right front tire can dip down to the soil surface to find traction rather than freewheeling.
“Nobody likes to see freewheeling tires spinning away on a stuck sprayer,” Criddle said.
“Long 20-inch suspension travel can help prevent it. We do this by giving each corner its own independent hydralink suspension. It’s totally independent of the other three corners. It has its own nitrogen accumulator, so it doesn’t depend at all on what the other corners are doing.”
Criddle said suspension wasn’t much of a consideration when farmers bought 600-gallon sprayers, but farmers are now buying mainly 1,400 or 1,600 gallon sprayers.
He said the ideal weight distribution is 50:50, and weight distribution on the Nitro 4000 series is always within four percent of that, whether the machine is dry or fully loaded.
Miller accomplished this by hanging the engine out the back and putting the boom out front.
“It’s part of our all-encompassing plan to take traction, suspension and compaction concerns and tie them all together. We gained something extra when we put the boom out front. Anyone who’s spent a day spraying in one of these machines says they’ll never go back to the conventional turn around sprayer. The fatigue factor drops tremendously. Now you can see every nozzle without cranking your neck.”
Miller Nitro 4000 sprayers start at about $200,000. For more information, contact Tim Criddle at 920-773-1181 or visit www.millerstn.com.
