ST. PAUL, Minn. – Michelin’s new SprayBib radial sprayer tire is designed to carry a fully loaded 1,300 gallon sprayer at typical highway transit speeds.
“Each tire can carry 14,330 pounds at speeds up to 40 m.p.h.,” said Michelin’s Michael Vandel. The D speed rated SprayBib is currently the only sprayer tire capable of that performance.
Vandel said as implement manufacturers build heavier, more powerful machines capable of higher transit speeds, it has created more need for tires that can handle them.
Along with mechanical factors, growers are becoming increasingly aware of the negative impact of soil compaction.
The new SprayBib is designated as a VF class tire, meaning it falls into the very high flexion category, which means a tire flexes 20 percent more than an IF rated tire.
Criteria for these classifications is established by the U.S. Tire and Rim Association. Few manufacturers have tires in either the IF or VF categories.
Vandel said the SprayBib tire flexes more than competitive products and runs at significantly lower pressures, creating a larger footprint for better traction, less slippage and an ability to spray in wet conditions.
“Lower pressure lengthens the footprint. Radial footprints get longer, not wider,” said Vandel.
“SprayBib operates at a pressure that’s 14 psi lower than the nearest competition. That means less compaction, more flotation, better traction and a better ride.
“You might gain one extra lug in contact with the soil.”
Vandel said the industry has not yet established a standard for measuring footprint, so each tire manufacturer uses their own methods. This makes it difficult to make a statistically valid footprint comparison.
However, the cyclic load table provides a valid means of comparing tires. Vandel said cyclic load refers to a fully loaded sprayer. As product gradually empties, the machine goes from full load down to minimum load.
“Here in North America, the tire manufacturer can designate a cyclic load tire that is fully loaded for only a short time, before you start spraying.
“Most manufacturers use the cyclic load table to rate their tire at full load, but only for 15 or 20 m.p.h.
“Once they approach road speed, the tires won’t handle a full load, even at 78 psi.”
Vandel said the SprayBib tire can safely carry 14,330 pounds at 40 m.p.h.
“And it only needs 64 psi at that speed. In the field, you can go down to 15 psi.
“The front tires run at 34 psi all the time. No adjustments.”
When radial tires were first introduced on cars and trucks four decades ago, the general reaction was that it looked the like tires were running flat.
Low inflation SprayBib tires cause sprayer operators to think the tires are going flat.
Jon Hauck, a custom spray operator near Sanford, Kansas, recalled putting SprayBibs on his sprayer.
“When we let the jacks out from underneath the RoGator, I actually laughed and thought these aren’t going to work,” said Hauck.
“The sidewalls squished out way too far and I thought it would be a problem.
“On the front axle, I’m running 34 pounds of air and on the rear axle I’m running 48 pounds of pressure.”
He said these pressures give him a smoother ride and better traction than previous tires he used.
“When fields are soft and a little bit muddy, you’re less likely to spin due to the low air pressure. You have a longer footprint so they grip the ground better in most situations.”
Vandel said Michelin field tests indicated that a SprayBib will last from three to five years, compared to a one or two year life expectancy for most sprayer tires.
Hauck already has 1,400 hours on his SprayBibs, without a tire failure.
SprayBib tires can be mounted on a standard rim. The outside diameter matches that of the tires it will replace, so ground speed calculations remain the same.