What applications and fitments do you recommend Rubber Tracks vs Tires and what are performance differences in terms of Traction, Fuel Economy, Soil Compaction and Roading?
Just like asking if apple or orange juice is better, asking if tracks or tires are better systems comes down to customer preference. Both systems have pros and cons, so it is important to understand the facts and benefits about each system and determine which is best for your operation. In many operations, it could be a combination of both systems.
When I ask users why they have tracks, the number one response I get is, “I want to get rid of compaction and the track has a much larger footprint area.” While it is true the total footprint area of a track is larger than a tire, the weight of the machine is not equally distributed under the track. When measuring the contact pressure of the track system, there are pressure spikes under each one of the boggy wheels. In wet or moist soils, the soil is damaged by the highest contact pressures, which would be under those boggy wheels. Firestone Ag has conducted studies on soil contact pressures on two and four track systems and wheeled tractors and has published technical papers with the American Society of Agricultural and Biological Engineers (ASABE). The results show:
- If the inflation pressure of the tires is less than 20 psi, tires transmit less contact pressure to the soil compared to tracks.
- From 20 to 35 psi, the tracks and wheel systems were comparable.
- If the inflation pressure of the tires is above 35 psi, the track system had lower contact pressure than the tires, a valuable investment.
However, there is still the perception that tracks reduce soil compaction when compared to tires, in all situations. What we have heard, anecdotally, is that the absence of a rut in the field means there must be no compaction. In wet soils, it does not matter which system is being used – compaction occurs with or without ruts. The rutting is a function on how the wheel and track system operate differently. A tire rotates and the tire lug needs to pull the tractor forward. The rotation of the tire causes a wave in front of the tire, and the tire is climbing out of the rut in wet soils. The lug on the track system is planted in the soil and the tractor is pushed forward. With the track system, there is not a wave of soil, so the track lug isn’t trying to climb out of a rut.
When looking at traction, track systems are most efficient at 0 - 3% slip while wheeled systems are most efficient at 5 - 9% slip. The lower slip range of the track system does give users more traction in the field, but that does not result in less fuel used. A track system takes more horsepower to rotate the track, which results in higher fuel consumption. When comparing a tracked tractor to a comparable wheeled tractor with the proper inflation pressure, they both will use similar amounts of fuel to complete a task. If the tires on the wheeled tractor are overinflated, that tractor will not develop the proper footprint, which results in less traction. In this scenario, a tracked tractor would use less fuel. For traction and fuel usage, both tractors will have similar fuel costs.
When transporting tractors on the road, a wheeled tractor can operate in the 25 to 30 mph range, while tracked machines are limited to 20 mph. The faster road speeds are better for minimizing wasted time between fields. However, the narrower width of a tracked tractor makes driving on the road less stressful compared to a 4WD tractor with duals, especially in areas of the country where roads may only be 15 feet wide.
The last item a customer should consider would be the total cost of ownership. Typically, a tracked tractor will cost more to purchase versus a similarly equipped wheeled tractor. Both systems require regular maintenance during the life of the tractor. For a tracked machine, it is important to make sure the track tension is set correctly and boggy wheels are greased or oil levels are maintained. On wheeled tractors, the inflation pressure must be set based on the axle load and maintained when operating the tractor. If the tractors are driven over abrasive stubble (corn or cotton), both tracks and tires will experience stubble damage. The track system has an advantage of not going flat because of punctures, but exposing the steel in the tracks still requires replacing the tracks, just like seeing the cords in a tire.
In the end, it comes down to what system works for a farm. Both systems will work similarly in most situations. If a farm is width-restricted or needs to operate in wet soil conditions, a track system may be the best fit. If an operation wants to minimize upfront costs and is able to match axle load to inflation pressures, the wheeled system may be the best fit. Remember that compaction will occur in wet soils regardless of what kind of system is running. Firestone Ag has experts and engineers available to help customers understand the pros and cons of both systems, as well as what Firestone products will work best in either system.
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 fibres and textiles. The BSAM family of companies also operates the world’s largest chain of automotive tire and service centres. 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.