Equipment World Digital Magazine
Issue link: https://read.dmtmag.com/i/407095
EquipmentWorld.com | November 2014 31 O nce known as one of the more difficult earthmoving machines to master, the crawler dozer – with the right technology – has become one of the easiest to run. The difference? In just ten years, hydrostatic transmissions have come to dominate dozers in the under-130-horsepower class. That combined with GPS machine con- trol have turned what was once a bucking mule of a machine into a smooth operator that can move mountains as well as skim the last few milimeters of dirt off the site as well as any motor grader. A look at the Equipment World Spec Guide shows just how quickly hydrostatic transmissions have come to dominate this class of machines. In 1999 there were 33 powershift transmissions and 25 hydrostats in the under-130-horsepower class. In 2004 there were 27 powershifts and 38 hydrostats. In our latest Spec Guide there were only nine pow- ershifts vs. 36 hydrostats and all of those powershift dozers were from one company, Dressta. Deere has been at the vanguard of this revolution. It introduced the first dual path hydrostatic dozer in 1976. Above about 160 horsepower most other OEMs (except Liebherr) switch to torque converter or mechanical transmis- sions. But Deere's lineup is 100 percent hydrostatic right on up to its biggest model, the 335-horse- power, 77,000-pound 1050J. So we traveled to Moline, Illinois, to talk to Deere's dozer experts to get a better idea on why hydro- statics have come to dominate the dozer world and what benefits they offer. Here's what they told us. No gears, no limits The first and most obvious benefits to a hydrostatic transmission in a dozer is that you have no gears, says Mark Oliver, crawler dozers product marketing manager. That translates into infinitely variable speed control. If you're just pushing dirt on flat ground in a straight line, the advantages of a hydrostatic drive dozer are obvious, says Keith Wilson, product consultant, crawl- ers and crawler loaders, because you don't have to shift gears. The crawler automatically slows down as the blade loads up and speeds product report | by Tom Jackson | TJackson@randallreilly.com THIS ISN'T YOUR DAD'S DOZER. IT ISN'T EVEN CLOSE Two pumps and two tracks, operating independent of each other with infinitely vari- able speed control, keep constant power regardless of the load on the blade or the underfoot conditions. THE HYDROSTATIC REVOLUTION