"World's Biggest" Tractor Returns Home To Work

We received a lot of mail a few years ago when we stated that a South African-built 4-WD ACO tractor was the biggest in the world (Vol. 19, No. 4).

Readers were quick to tell us about other tractors that have attempted to lay claim to the title, "World's Biggest". One frequently mentioned candidate was Versatile's Big Roy, an 8-WD, 600 hp giant that was built as a prototype and is now on display at a farm museum in Manitoba. We also got an earful about the Big Bud "747" that was built 20 years ago in Havre, Mont.

The 4-WD Big Bud was built by Northern Manufacturing, in 1978. It measures 22-ft. wide by 29-ft. long with a cab that tops 14 ft. It's powered by a 16-cyl. Detroit diesel engine retrofitted with the biggest injectors available to produce a total horsepower rating of 980. The tractor weighs 100,000 lbs. without fuel in its 1,000-gal. tank or ballast in its four specially built, 8-ft. tall duals.

The tractor was originally built for the Rossi Brothers in Bakersfield, Calif., where it was used to deep rip cropland to a depth of 30 in. with a 15-shank ripper built specially for the tractor. It worked 15 acres per hour at 6 to 6 1/2 mph, and it was said that when the ripper was pulled out of the ground at the end of the day, the points glowed red hot.

The big tractor replaced the three Cat D-9's used to do the work before.

The tractor was used in California for 11 years before being purchased by Willow Brook Farms in Indialantic, Fla., where it was used for deep ripping until last year. Its engine and rear differential were overhauled while the tractor was in service at the farm.

When the tractor came up for sale last fall, two farmers near Big Sandy, Mont., acquired the tractor after officials from Big Equipment Co. (which services and sells used Big Buds) helped locate the one-of-a-kind tractor.

Robert and Randy Williams were interested in the tractor for nostalgic reasons but they also wanted to put it to work on their farm. The tractor had about 8,000 hours on it, and the original Canadian-built tires had at least 50 percent tread left on them, says Ron Harmon, owner of Big Equipment.

The Williams brothers restored the tractor over winter. It was taken down to the original metal, repainted the original white color and decals were replaced. A few axle parts also had to be replaced. The tractor will pay off, say the Williams, who use it to pull an 80-ft. Friggstad chisel plow.

"It works over an acre per minute," says Robert. "You can do 60 or 70 acres an hour at 6 1/2 to 7 1/2 mph. It takes only two weeks to work 8,000 to 9,000 acres for small grains under optimal conditions. We put 300 hours on it this spring, no problems."

The tractor uses two to three qts. of fuel per acre, a reasonable figure, they say. As for ground pressure, that's been measured at less than 5 psi's, dry. Fully ballasted and fueled, it would exert only 6 or 6 1/2 psi's, Harmon says.