When you hear the term “skid-steer,” the iconic small wheel loader is what usually comes to mind. But skid-steer technology has been used in other machines as well.
One was the Balmar loader/backhoe conversion of Ford wheel tractors. Along with the loader and backhoe, Balmar also provided a chain drive for the tractor that operated on a skid-steer principle. Another much more successful application of skid-steer design was the world’s first successful wheel dozer, the LeTourneau Tournadozer.
After building a test bed for the wheel dozer idea by mounting a blade to the back of a John Deere R wheel tractor, R. G. LeTourneau developed the first true wheel dozer as a prototype in late 1945. Another prototype followed a year later, and production of the first of several versions began in January 1947.
Along with horsepower for the biggest models far greater than any crawler tractor of the time, the rubber tires gave the Tournadozers three key advantages over crawler tractors: roadability, greater speed, and the ability to work in sand and other soft, abrasive materials without the wear that undercarriage parts suffered. However, the tires were at a considerable disadvantage in rock that could chew up the treads and sidewalls.
Rather than a conventional steering wheel, these pioneering machines used a form of skid-steering to maneuver. Brakes were applied to either the left or right side wheels while disengaging power to them, so the powered wheels turned against them. Unfortunately, this greatly hindered the tractor’s efficiency in any deviation from a straight line. Although the steering controls evolved from a pair of levers to electric switches, the skid-steer technology lasted until the last descendants of the Tournatractors were sold by Wabco in 1972.
The Historical Construction Equipment Association (HCEA) is a 501(c)3 non-profit organization dedicated to preserving the history of the construction, dredging and surface mining equipment industries. With over 3,800 members in twenty-five countries, our activities include publication of a quarterly educational magazine, Equipment Echoes, from which this article is adapted; operation of National Construction Equipment Museum and archives in Bowling Green, Ohio; and hosting an annual working exhibition of restored construction equipment. Our 2019 show will be September 13-15 at our Museum in Bowling Green, Ohio. Individual memberships within the U.S. are $35 for one year, $66.95 for two years and $99.95 for three years. We seek to develop relationships in the equipment manufacturing industry, and we offer a college scholarship for engineering and construction management students. Information is available at www.hcea.net or by calling 419.352.5616 or emailing [email protected]