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Big tractor, big tires on world’s largest tractor

It took nothing less than a Titan to get replacement rubber on Big Bud 747 after four decades

The world’s largest ag tractor, the Big Bud 747, built in 1977, had its original tires replaced with a full set of Goodyear/Titan LSW1400/30R46 tires last summer.

If you are a consumer of ag-related social media, you’ve likely seen online video of one of the most memorable events involving classic North American farm machinery. The one-off Big Bud 747, which had been stored at the small-town Heartland Museum in Clarion, Iowa, was brought out into the sunlight for a very special event last summer. The 40-plus-year-old tires, originally installed on it in the Havre, Mont., factory when it was built, were finally replaced, which means the world’s largest ag tractor was refitted with a set of the world’s largest ag tires.

The replacement was necessary because the Bud’s original tires were deteriorated beyond repair. The original tires were built by the United Tire Company of Canada, which has since stopped making custom tires. With poor rubber and no known replacements for them, there was no choice but to retire the Big Bud a few years ago. Unable to work, it was put on display at the Heartland Museum, where museum owners built a shed just for it.

However, the recent introduction of Goodyear Optitrac LSW1400/30R46 tires meant there was now an opportunity to give the Big Bud a second lease on life.

The Bud’s owners, Robert and Randy Williams of Big Sandy, Mont., have since brought the tractor back to their farm and put it to work. One task included fall tillage with an 80-foot-wide Friggstad D7-80 chisel plow.

The brothers bought the tractor in 1997 from the original owners, who were cotton farmers in California. The Williams brothers used it for cultivating until a tire suffered irreparable damage, making it unusable — until now, that is.

Special spacer and rim modifications were required to install the new LSW tires on the Big Bud. This is the first time the LSW1400/30R46 tires were ever mounted as duals. photo: Goodyear/Titan Tires

World’s largest ag tires

With some special help from Titan International, manufacturer of Titan Tires, Titan Wheels and Goodyear Farm Tires, the legendary 1,100 horsepower tractor is back in fighting form. The tractor was re-outfitted with eight of the largest ag tires in the world, installed in their first-ever dual configuration.

The new tires use a low sidewall design (hence their LSW designation) and stand a little lower than the originals, which were roughly eight feet in diameter. The lower stance of the new rubber means the tractor’s top road speed of 12 miles per hour will be diminished slightly. And it also required modification of the rims and spacers for the dual configuration, which was handled by the U.S. company World Rim and Wheel.

The Williams brothers have had an association with Big Bud since the days when it was originally building tractors. They say they were inside the plant and saw the 747 being assembled on the factory floor, taking a few pictures of it then for posterity.

One-of-a-kind tractor

The Big Bud 747 is the only model of its kind. Only one was built. The tractor pulls 1,100 horsepower out of a 16V92T 16-cylinder, two-cycle Detroit Diesel. It rolled out of the factory doors in 1977, and mated with a suitable implement, it’s capable of cultivating about three acres per minute. Towering over today’s largest 4WD tractors, the 747 is an absolute giant. It’s 27 feet (8.23 metres) long, 25 feet (7.62 metres) wide and 14 feet (4.26 metres) tall. It holds 1,000 gallons (3,785 lites) of fuel and weighs more than 135,000 pounds (61,234 kilograms) when fully ballasted.

With the LSW tires and rims weighing in at about 5,000 pounds each, making the changeover required some heavy lifting. photo: Goodyear/Titan Tires

The tire changeover in mid-July last year became something of a media event at the Heartland Museum. After the work was completed, the tractor was paraded through Clarion, with the local police providing an escort, due partly to the fact the tractor used up the entire width of many of the town streets.

“It’s definitely a legend,” said Nick Welker of Welker Farms, who was on hand to see the tire change. Welker is a Montana farmer who owns several Big Bud 600 horsepower tractors and is a Big Bud enthusiast. He travelled to Iowa to capture the transformation on video for his popular YouTube channel.

“The look of it, the size of it, the sound of it, the story of it … it would sadden a lot of people if this thing got cut up and sold to scrap,” said Welker.

“It’s the perfect match to put the world’s largest ag tires on the world’s largest ag tractor,” said Scott Sloan, Ag Product Manager/Global LSW at Titan. “We’re just proud to be part of this project.”

With the LSW tires and rims weighing in at about 5,000 pounds each, making the changeover required some heavy lifting. photo: Goodyear/Titan Tires

The Williams brothers brought the 747 home last fall to run it during harvest and then to display it in Montana at a to-be-determined location. Installing the new tires on the Bud was also a featured presentation of the U.S. Farm Progress Show’s Virtual Experience, which initially ran September 15-17, 2020.

For Big Bud enthusiasts, the Williams Brothers sell a 1/64 diecast model of the 747 complete with its new shoes. It can be ordered online at for US$100.

About the author


Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.



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