Tire or track,” asks Mitas’ promotional material announcing the completely new PneuTrac ag tire. It seems like a fair question given how odd this tire looks, and how differently it performs when mounted on a rim. Tire manufacturer Mitas chose to introduce the prototype PneuTrac concept to the public at November’s Agritechnica in Hanover, Germany. While it isn’t yet market-ready, it was definitely turning heads at the show.
“This concept shows that we are thinking outside the box of current tire-producing practices with a strong focus on what will benefit farmers,” said Andrew Mabin, Mitas’ sales and marketing director, in a press release. “We still have some way to go to bring the concept into a commercial product, but the initial results look very promising, challenging the design of the conventional tire and cost of tracks.”
The PneuTrac concept was actually developed by Galileo Wheel Ltd., of Israel, who is partnering with Mitas to turn the concept into a commercially-available product.
“The basic concept is we are approaching the carcass, or tire design, in a different way,” said Avishay Novoplanski, founder of Galileo Wheel Ltd., and inventor of the PneuTrac. “In all existing tires, the carcass is a U shape revolved around the rim. As the tire works, the sidewall is deflecting. The (standard) tire tries to follow the contour of the ground and increase its footprint, and it can do that to some extent. But if you deflate it too much, the footprint buckles in the centre (of the tread). With this (PneuTrac) design, the sidewall is kind of a V shape, like an accordion. All the vertical load is carried only by the air, not by the carcass.”
The footprint of the PneuTrac is significantly larger than that of a standard tire of equal size, providing up to 53 per cent more ground-contact area according to Mitas. That increases traction and improves power transfer to the ground, boosting tractive power by up to 48 per cent, the company adds. The increased footprint is significantly elongated compared to standard tires, something the company refers to as a “track effect.” And it gives the tire a flat-bottomed appearance when it’s mounted on a vehicle.
Because that load is distributed evenly across the tread face by the internal inflation pressure, the ground pressure it exerts is evenly distributed across the entire surface. That provides an advantage over tracks, which have higher point loads on the track under the bogie wheels.
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“It’s a standard pneumatic tire and you’d like to keep some air pressure to evenly distribute the load, yet you could go with no air pressure at all,” Novoplanski said. “We conducted some tests with our nominal air pressure, which in that case was 0.8 (Bar, about 11 p.s.i.). Then just for the sake of it we finished it with zero air pressure. It was functioning very well with no air at all.”
So if you lose air pressure, you won’t end up with a flat, as you would with a normal tire.
“If something happens in the middle of a row, you could certainly finish the row, probably finish the day,” he explained. “So you’re not stuck (with a flat).”
But when looking at the highly deflected tire, it seems to be ready to slip off the rim or have no lateral stability at all in a corner. The reality is exactly the opposite, according to Novoplanski.
“Those tires actually have grater lateral stability with no air pressure at all than normal tires inflated to their nominal pressure,” he said. “That allows very high deflection at very low pressure, still maintaining great steering and manoeuvrability without creating heat or damaging the tire.”
“You can work in the field with very low pressure and very high deflection since the relation between the internal pressure of the tire and ground pressure might be slightly different than a standard tire. The physics are the same, of course, but the mechanics are different.”
The PneuTrac design is also less likely to suffer damage from field hazards, because its sidewall isn’t exposed beyond the tread, so it’s protected from puncture hazards. If an ordinary tire has a punctured sidewall, it likely means the tire is finished. The PneuTrac on the other hand has a much thicker sidewall than a normal tire, and it can be repaired in the unlikely event it does get damaged.
“In ag applications you go with very low pressure, so the sidewalls (of conventional tires) tend to bulge out,” Novoplanski explained. “What is bulging out is the thinnest and weakest part of the tire. With this (PneuTrac) tire, it won’t bulge out, so it is less likely something will hit the sidewall.”
The PneuTrac will also fit on any standard rim for a comparable tire size.
Although the tire isn’t yet in production and firm pricing hasn’t been set, Novoplanski thinks it will likely have a little higher retail cost than a standard tire when it does hit the market. “There is more sidewall here so there is more material, which means more cost,” he said. “But by all means when you compare the additional costs to the additional advantages, it’s a very clear answer.”
“It is a standard pneumatic tire; it’s round and it’s black,” Novoplanski continued, summing things up. “It’s manufactured in a standard facility from the same moulds, yet it is totally different in its structure and physics. It will take years — but not many years — and it will be in the market.”
For a video look at the PneuTrac tire, visit grainews.ca/videos online.