July 19, 2007

Ag engineer: Proper tire use not gaining traction with all farmers

Poor tire traction during fieldwork can increase fuel and labor costs, said Dennis Buckmaster, who specializes in agricultural mechanization and machinery. The right combination of tire slippage, tire air pressure and axle weight produces higher traction rates, known as "tractive efficiency," he said.

Buckmaster will lead a session on tractor tires during Purdue's Top Farmer Crop Workshop. The 40th annual event takes place Sunday through Wednesday (July 22-25) in Pfendler Hall on Purdue's West Lafayette campus.

Buckmaster's talk is scheduled for 10:55 a.m. Tuesday (July 24).

Some tire slippage is necessary for maximum tractive efficiency, especially if the tractor is pulling an implement, Buckmaster said. When tires slip, travel distance is shorter per revolution compared to the unloaded, or no-slip, condition.

"One misconception farmers have is if they see tires slipping they think it must be bad. That is not necessarily bad. Some slip is good," Buckmaster said.

"When we study tractive performance there is an optimal level of slip for every field condition. Generally, that optimal level of slip is somewhere between 8 percent and 15 percent. As tires slip more they generate more pull. Of course, there is a tradeoff between generating more pull and slowing down because of the slip. But the optimum level of slip that maximizes tractive efficiency is not zero."

Tire sizes and the tractor's weight distribution also factor into tire performance, Buckmaster said.

"A common error farmers make is choosing tires that are too wide and not as large in diameter as would be optimal," he said. "Another common error is tractors weighing too much or weighing too little.

"Having too much weight on the wrong axle can cause problems. If there is improper ballast on the front axle, then the vehicle is going to steer hard and a farmer might get a little extra power hop, and they won't get the amount of traction that they'd like to get. If there is too little weight on the front and too much on the rear, then, depending on the implement being pulled, the front tires could be raised off the ground, a farmer might experience poor steering and there could be reduced traction."

Like automobiles, tractors perform better with properly inflated tires.

"The right tire pressure can make as much as a 10 percent improvement in tractive efficiency," Buckmaster said. "Tractive efficiency affects tire wear, fuel consumption and the amount of time required for the work. That, in turn, affects labor, machine time and the time it takes to get a job done. A job done in less time frees up time to do more work."

Buckmaster's workshop presentation includes tips on tire selection and use, as well as ways to calculate tractive performance. He'll show how to use tractor manufacturer Web sites to aid in tire purchase decisions and demonstrate an online spreadsheet that calculates proper ballast.

The presentation is among more than 50 planned for the Top Farmer Crop Workshop. As its name implies, the workshop is geared toward leading crop producers who use cutting-edge technology and production practices. Workshop topics range from new farm technology to crop management practices to agricultural issues such as the 2007 Farm Bill. Sessions are led by speakers from Purdue, other universities and the agricultural industry.

Workshop registration is $250 per person and $75 for each additional person from the same farm. Fees include two meals, coffee breaks, a workshop proceedings notebook for each farm and the use of Purdue computers for budgeting analysis. Lodging and other meals are extra.

Enrollment is limited. Registration forms and a complete list of workshop sessions are available on the workshop Web site, at https://www.agecon.purdue.edu/topfarmer. On-site registrations will be accepted as space permits.

Registration also can be completed by calling Tom Robertson of Purdue's Conference Division at (765) 494-7220.

Purdue's Department of Agricultural Economics sponsors the workshop.

Writer: Steve Leer, (765) 494-8415, sleer@purdue.edu

Source: Dennis Buckmaster, (765) 496-9512, dbuckmas@purdue.edu

Ag Communications: (765) 494-2722;
Beth Forbes, forbes@purdue.edu
Agriculture News Page

Note to Journalists: Other farm-related story ideas are available on Purdue Agriculture's Farming 2007 Web site at https://www.agriculture.purdue.edu/farming

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