A couple things to consider before buying your subcompact tractor: horsepower and number of axles.
GRIT's Guide to Subcompact Tractors
When you are looking at a lawn tractor, higher engine horsepower numbers relate to the size of cutting deck the tractor can efficiently run – the wider the deck, the more horsepower required. However, there is a tendency among manufacturers to seek bragging rights to the most powerful lawn tractor out there – for the consumer, this horsepower competition means that most lawn tractors are much more than adequately powered. You can easily drive a 50-inch-wide cutting deck with a 15-hp engine, which means that 26 hp really isn’t necessary. Further, the transaxles on lawn tractors would quickly self-destruct if they were asked to deliver anywhere near the full 26 engine hp to the ground in a tough pulling situation.
Thankfully, lawn tractors are so light that, in most cases, the rear wheels will start to spin long before axle shafts will twist in two when the transaxle is overpowered.
Subcompact tractors are designed to convert more of that engine horsepower into ground-engaging pulling power (drawbar horsepower). These machines are built for maximum traction, while keeping sufficient reserve power to run implements (PTO horsepower).
So, if you truly have a need for a 54-inch wide cutting deck on a lawn tractor, then the 25-hp model might make sense. However, you will be able to safely and effectively pull much more weight with an 18-hp diesel subcompact tractor, and it would have no issue driving a 54-inch mowing deck at a slightly lower ground speed than the lawn tractor. The garden tractors fall between the lawn tractors and subcompact tractors in terms of traction, but overlap completely in terms of engine horsepower rating.
The two-wheeled garden tractor has a long history throughout much of the agricultural world. These tractors are constructed with cast-iron clutch, transmission and axle housings, much like the engine-to-axle components on a subcompact tractor – only on a much smaller scale. The two-wheeled walking tractor is controlled from behind, or the side, or the front (while running in reverse) with an adjustable handlebar, and it can be equipped with grader blades, land plows, rotary tillers, snowblowers, rough country mowers, miniature hay mowers, miniature hay rakes, miniature hay balers and even dump-cart bodies.
Modern two-wheeled tractors are quite popular in vineyards and berry patches and on other smaller agricultural enterprises, especially those with considerable slope. Although they are not inexpensive (expect to pay at least $2,000 for a good two-wheeled tractor with tiller), two-wheeled tractors make a lot of sense for folks who already own a mower for the lawn and need to intensively work relatively few garden or field acres.
Hank Will raises hair sheep, heritage cattle and many varieties of open-pollinated corn with his wife, Karen, on their rural Osage County, Kansas farm. His home life is a perfect complement to his professional life as editor in chief at GRIT and Capper's Farmer magazines. Connect with him on Google+.