Tire Expert Center
Feb 13, 2018
Do you foresee variable air pressure systems becoming popular on US Ag Equipment, how is tire performance affected, and what yield, traction and transport benefits can a grower expect to receive?
Yes, central tire inflation pressure systems (CTIS) will become more popular on agricultural equipment in the future. When properly used, these systems can lead to improved traction in the field and reduced soil compaction which can improve crop yields. These systems allow farmers to quickly manage the inflation pressure in the tires when the axle weights on equipment changes between field and road. This is why CTIS systems are becoming popular in Europe. Farmers in Europe use a lot of 3-point mounted equipment, and the axle loads change between the field and the road. In North America, not all tractors on a farm will need to be equipped with a CTIS system, and some farms will not need these systems at all. Today, when farmers are looking at purchasing an aftermarket CTIS system, I make the following recommendations to help them decide if these systems will or will not make financial sense.
A CTIS system makes sense for tractors when the axle weight changes between road transportation and field operation. The most common scenario in North America would be the planter tractor with a 2-point mounted, front fold planter. During road transport, the planter wings fold forward and the planter weight is carried on the rear axle of the tractor and only 4 tires on the planter. Weighing a 235 horsepower MFWD tractor with a 16/32 row front fold planter (Figure 1), the rear axle weight of the tractor is around 27,000 pounds during road transport. When the planter is unfolded in the field, the weight of the planter is now taken off the rear of the tractor and is being carried primarily by the 8 tires on the planter. Now the rear axle weight of the tractor is 16,500 pounds. With dual 480/80R50 tires on the rear of the tractor, the farmer would need to set the inflation pressure to 23 psi to carry the 27,000 pounds for road transport. When the tractor is in the field, 23 psi is an overinflated condition to carry the 16,500 pounds. Having the higher inflation pressure will not damage the tire, but it does reduce the tire’s footprint. With a smaller footprint, the tire cannot fully transmit power to the ground. This reduces traction in the field and increases fuel consumption. With a CTIS system the farmer could inflate the rear tires on the tractor to 23 psi on the road, and when they get to the field the inflation pressure could be easily lowered to 12 psi. This would give the farmer the optimal footprint and all the tire to generate the maximum traction. After the field is planted, the farmer would push a button, and the rear tires would be inflated back to 23 psi for road travel. On planter tractors, I encourage farmers to explore the idea of purchasing a CTIS system.
The CTIS system doesn’t make financial sense on tractors where the axle weight doesn’t change between road transport and field use, like tractors pulling drawbar tillage and planting equipment that transfers little to no tongue weight to the tractor. Using the same 235 horsepower tractor only on a field cultivator or disc, the rear axle weight of the tractor remains consistent at 16,500 pounds and the inflation pressure required is 12 psi all the time. The farmer would not benefit from a system that changes pressures between road and field. In this case, it makes more sense for the farmer to look at a tire pressure monitor system (TPMS). These systems are similar to the pressure monitor on newer cars and trucks. The TPMS display can be placed in the cab of a tractor and if the pressure is low it will notify the farmer and show which tire needs to be inflated.
While CTIS systems are not an option on all new tractors, there will likely be an increase demand for these systems as options from the factory. If you feel your operation could benefit from CTIS, I encourage farmers to look at how they are using their tractors and what tire size is on the tractor. If the tractor does have different axle weights between road transport and field, there are after-market systems available in North America to add to the tractor. By matching the inflation pressure to the axle load, the tire will be developing the maximum footprint, generating the most traction and not wasting time and fuel in the field. Having the ability to use the lowest recommended inflation pressure also minimizes soil compaction, which should result in better crop yields.
About Bridgestone Americas, Inc.:
Nashville, Tennessee-based Bridgestone Americas, Inc. (BSAM) is the U.S. subsidiary of Bridgestone Corporation, the world’s largest tire and rubber company. BSAM and its subsidiaries develop, manufacture and market a wide range of Bridgestone, Firestone and associate brand tires to address the needs of a broad range of customers, including consumers, automotive and commercial vehicle original equipment manufacturers, and those in the agricultural, forestry and mining industries. The companies are also engaged in retreading operations throughout the Western Hemisphere, and produce air springs, roofing materials, and industrial fibers and textiles. The BSAM family of companies also operates the world’s largest chain of automotive tire and service centers. Guided by its One Team, One Planet message, the company is dedicated to achieving a positive environmental impact in all of the communities it calls home.