Contents

Feature Article

The Small Tractor FAQ

Big Wheels

[Copyright 1987, 1988 by Ronald Florence]

Tractors look like what they are supposed to do. With gears, levers, pulleys and hydraulic cylinders instead of mysterious black boxes and plug-in circuit boards, a tractor is a machine you can understand, an appealing steel and rubber symbol of an honest day's work. One thumb through a tractor manufacturer's brochures and it's hard not to imagine yourself pulling a moldboard plow, steering a sickle-bar cutter through blue-tinged rows of alfalfa, or hauling a heavy hay wagon. Buy a big enough tractor and you can not only till the fields, but dig ponds, strip mine your woodlot, or pull a combine.

There was a time, in the mythical heyday of the American working farm, when the choice among small tractors was simple: you could buy a one-bottom or a two-bottom tractor, measured by whether the moldboard plow it would pull could turn one or two rows at a time. Today, tractor dealers offer more choices than the souk in Jerusalem. There are garden tractors with more horsepower than the traditional two-bottom tractor; two-wheel tractors with accessory lists that include big-league items like plows, discs, sickle-bar cutters, and flail mowers; and ATVs (All-Terrain Vehicles) with seeder/spreader and spraying attachments. Machines with the familiar plain vanilla shape -- big wheels in the back and small wheels in the front -- come in sizes from monsters that would dwarf a small farmhouse to toylike machines that can scarcely mow a tract house lawn. There are machines with four wheels the same size, big wheels in the front and little wheels in the back, loading platforms front and/or rear, row tractors shaped like arthritic spiders, and machines you don't recognize as a tractor until the salesman explains what it does. It's enough to turn a city slicker long-toothed in wonder.

Special needs require specialized machines, whether a commercial front-mount mower for an estate lawn, a row tractor for garden crops, a two-wheeled tractor for intensive cultivation of a small plot, or a tracked machine for grading. For the common tractor chores on most small farms and country places -- mowing lawns, clipping pastures and meadows, hauling firewood, stones, manure and brush, mowing and raking hay, and light cultivation and tillage -- the most versatile machines are garden and utility tractors, which are scaled between the smaller riding mowers and lawn tractors, and full-size general purpose tractors.

Garden tractors are primarily mowing machines, powered by ten to twenty horsepower air-cooled gas engines, although a few are available with diesel power. The larger models have hydraulic rockshafts, auxiliary hydraulics for snow blades and throwers, category "0" three-point hitches, and rear PTOs (see sidebar). Most are offered with belly-mount mowers. The smaller lawn tractors have eight to twelve horsepower gas engines; they generally lack hydraulics and a three-point hitch, although some have provisions for mounting a snowblade or other accessories.

New, a garden tractor can cost anywhere from $2500 to $7500; the belly-mount mower will add another $400 to $1000. Adding a three-point hitch, a rear PTO, and hitch-mounted implements will quickly jack the price up. There are companies like Brindley which specialize in small implements for garden tractors, including miniature plows, disc harrows, and field cultivators. For powered accessories, like grooming mowers, rotary cutters, sickle bar cutters, firewood splitters and tillers, you are generally restricted to the manufacturer of the tractor for accessories; a John Deere grooming mower won't fit a Ford garden tractor.

Utility tractors, the Japanese contribution to small-scale farming, are small diesel tractors, generally available with four-wheel drive, and in horsepower ranges from twelve up to sixty or more. The Kubota and Satoh Beaver brands are well-known; some of the others are better known under American brand names. John Deere, for example, imports the Yanmar tractors, with a few changes and a coat of green paint. The bigger utility tractors can handle almost any piece of equipment on a small farm; with four-wheel drive, low centers of gravity, and the high-torque of diesel power, they are more efficient than substantially larger older tractors. The smaller utility tractors, in the fifteen to twenty horsepower range, are ideal for mowing large lawns, meadows and pastures, loader and hauling work, and small-scale tillage and cultivation. Utility tractors are generally equipped with three-point hitches and standard (540 rpm) PTOs.

You can expect to pay anywhere from $5500 to $20,000 for a utility tractor, with the cost escalating rapidly as the size of the tractor increases, and as you pile on options like a hydrostatic transmission, power steering, and selective hydraulics. Unless you shop for used implements at farm auctions, you can expect to pay $1000 or more for a belly-mount or three-point hitch grooming mower, $600-$2000 for a rotary cutter, and anywhere from $500 for a simple rear-mounted loader to $2000-$3500 for a front loader.

The small diesels that power these utility tractors are rugged, standardized engines, many of them manufactured in Japan. In tractor service, they require minimal service and maintenance: no fiddling with points and plugs, no worries about moisture in the ignition system, no carburator to adjust. Give them clean fuel and plenty of clean air, scheduled changes of oil and the oil filter, and a shot of lube in the zerk fittings, and they run and run and run. With the exception of a few oddball Chinese tractors, diesels are liquid-cooled. The coolant system needs to be checked, flushed and refilled periodically, but the chore is generally easier than servicing a passenger car, because most tractors have better access to the engine than a car.

The newer small gasoline engines, like the Onan and Kohler engines, and even the ubiquitous Briggs & Strattons, are much improved over their sometimes balky predecessors, and a gasoline powered small tractor is cheaper to buy than a diesel. If you're handy you can certainly change spark plugs and adjust the carburator yourself, but no matter how diligent you are, a gasoline engine probably won't last as long as a diesel, will require more maintenance, and won't run as economically.

As a shorthand for identifying tractors, horsepower is about as useful as overall length for boats: it gives you a "ballpark" figure, but it doesn't really tell you what the machine can do. A fifteen-horsepower diesel utility tractor with four-wheel drive can do a lot of hauling and pulling, including loader work, lifting logs, and pulling a four-foot brush hog. A twenty-horsepower garden tractor can mow lawns and plow driveways, but would have trouble on rough ground and with heavy hauling. The difference is in traction, clearance, useful horsepower, and the availability of implements. The diesel engine of the utility tractor provides more torque at slow tractor speeds; the bigger wheels and heavier weight provide greater traction; the higher clearance allows the utility tractor to romp over terrain where the garden tractor would need an airlift; and the three-point hitch and standard PTO enable the owner to use implements that are rarely available for a garden tractor. The trade-off is that the garden tractor is more maneuverable on the lawn or scraping snow off the drive, and the lighter weight of the garden tractor is less harsh on a manicured lawn.

Weight, wheelbase, and width are as important as horsepower in determining what work a tractor can do. It doesn't take much horsepower to pull a loaded wagon of hay or firewood, especially when the tractor is geared down to those superlow gears that pull at one mile per hour. But try to stop a fifteen hundred pound tractor towing a three-ton wagon on a downhill slope and you may end up part of a steel pretzel. Wheelbase and overall length determine the loads that a tractor can safely carry in a front loader or on the rear hitch. Heavy loads play havoc with the stability of short-wheelbase tractors.

The standards for measuring horsepower are about as uniform as the standards for measuring the output of stereo equipment. The usual comparison is the rated PTO horsepower of tractors equipped with standard (540 rpm) PTOs, but even there, some manufacturers rate the tractor at maximum PTO speed instead of the standard 540 rpm. The real utility of horsepower ratings is in selecting implements for the tractor; or, if you are wise, in selecting a tractor after you have picked the implements you will need. For example, a three-point hitch grooming mower needs a tractor that puts out 15-25 horsepower at the PTO. Less horsepower won't turn the mower; more horsepower may burn out the gear box on the mower.

With the exception of tractor-pulls and wagon-hauling, tractors don't do much useful work by themselves. If you want to mow, you need a mower. To clip pastures and meadows, you need a brush hog (rotary cutter), sickle-bar cutter, or flail mower. To haul manure and stones, you need a loader. To pull fence posts, lift logs, or hold a hog over a scalding drum, you need a boom crane. The list is endless: spreaders, blades, mulchers, plows, discs, cultivators, posthole diggers, sprayers, tedders, rakes, back-hoes, utility platforms, bale handlers, rock pickers, rotary tillers, balers, seeders. If you have specialized needs, there are tractor-driven or tractor-pulled accessories to solve the problem: rippers for compacted soil, chippers for orchard clippings, box scrapers for landscape grading.

Fortunately, you don't always need the perfect implement to get a job done. A brush hog is ideal for clipping pastures; it also does a decent job of mulching orchard clippings. A post hole auger is designed to dig holes; it can also be adapted as a boom crane. A loader is perfect for handling manure; it can also plow the snow off your driveway, regrade the gravel, and haul brush, stones, or firewood. If you had a lot of driveways to plow, you might want a blade instead; if you had lots of gravel or dirt to grade you might want a box scraper; but the loader will do it. The trick is to select versatile implements, with the emphasis on the jobs that are most important on your place. Once you know which implements you will need, you can pick a tractor to pull them.

The fox knows many things: a versatile tractor with enough implements may be able to do all the jobs that need doing on your place. It may take some trade-offs: a tractor big enough to pull the five-foot rotary cutter you need to keep the brush down, or rugged enough to haul logs from boggy woods, may be too big to pull a grooming mower for the lawn. A tractor compact enough to maneuver around the lawn may be too delicate to take on the rough ground of an overgrown meadow.

If you use a tractor mostly for two or three jobs, such as mowing and loader work on a horse farm, you may want to search for a tractor that can handle a particular combination of implements: a belly-mount mower that will raise to a high clearance, together with a loader that can be lifted out of the way, would enable you to mow and load barn scrapings without changing implements.

The alternative is the hedgehog: he does one job and does it very well. Instead of using a shed full of implements to adapt the tractor to different jobs, you can use a shed full of machines, each suited for a single job: a commercial front-mounted mower for the lawn, a two-wheel rotary tiller for the garden, a grinder-mulcher for the clippings, an old John Deere B to drive the cordwood saw. If you have a big enough checkbook to afford them, a big enough shed to store them, and time to keep them all running, you could end up with the perfect machine for each chore. Remember, though, that no matter how carefully you lay them up, internal combustion engines are happier running than sitting on the sidelines. A machine that sits idle too long may balk when it is called on for service.

Whether you go for one versatile tractor, or a collection of specialized tractors, the machine has to be sized for the job. Here it is important to distinguish between different kinds of work. Ground-engaging work, pulling implements that dig or cut into the earth, like a plow or a disc, makes the biggest demands on a tractor. To pull a plow you need horsepower, ground clearance, and traction. Some garden tractors include ground-engaging tools, like miniature moldboard plows, among their available implements, but a plow pulled by a garden tractor, no matter what the horsepower, does more scratching than turning of the earth.

Cutting tools, like a mower or a brush hog (rotary cutter) demand less pulling power from the tractor, but a specific range of PTO horsepower. Some cutting tools, such as a sickle-bar cutter, require a good-sized tractor because of the asymetrical loads of the cutter extended from one side of the tractor. Without adequate ballast in front and traction from the offside rear wheel, the tractor tries to spin on the spot instead of moving straight ahead. In many situations, terrain, rather than horsepower, can be the limiting factor. A brush hog that cuts two-inch saplings may need only ten PTO horsepower to turn the blades, but the tractor has to be big enough and rugged enough to pull the cutter through the overgrown meadow.

Finally, there are lifting tools, like loaders and boom cranes, which depend on the hydraulic capacity of the tractor. Usually the problem is not the load capacity of the three-point hitch or the loader, but the size of the tractor. If you are going to lift logs in the woods, you need clearance, stability, and tires that will not stick in the muck. And while a loader may advertise itself as having a capacity of seven-hundred pounds, if the opposite end of the tractor isn't sufficiently counter-weighted, you may find the hydraulics lifting the end of the tractor instead of the pile of rocks in the loader.

Implements all have to be hitched onto the tractor, which for most tractors larger than a lawn tractor means a three-point hitch. The standardized three-point hitches, in sizes from category "0" for garden tractors to category "3" for agricultural behemoths, evolved to remedy the mutual imcompatability of implements and tractors from different manufacturers. Implements which fit a three-point hitch are fastened by lynchpins to three arms, two hydraulically (or in some very small tractors, mechanically) controlled lower arms, and a free-pivoting upper arm, or toplink. One of the lower arms can be adjusted to level the implements from side to side, and the length of the toplink can be adjusted to level the implements from front to rear. Depending upon the vertical distance between the attachment points of the lower arms and the toplink, the implement will either be lifted almost vertically by the rockshaft control, or will be tilted back, toward the tractor, as it is lifted. It takes about five minutes to hook an implement to a tractor with a three-point hitch.

Most utility tractors have category "1" hitches with lifting capacities from 800 to 1500 pounds; garden tractors are usually equipped with category "0" hitches with lifting capacities of 400 to 700 pounds. There are far more implements available for category "1" hitches than for the smaller category "0" hitches, and in many cases implements for the smaller hitch are more expensive. If you are planning to use a mower on the three-point hitch, it is a good idea to look for a "float" feature, which allows the lower arms to float independently when the mower goes over uneven ground.

There are alternatives to a three-point hitch, including coupler-hitches on small garden and lawn tractors, and a variety of proprietary hitches on older tractors. If the tractor doesn't come with all of the implements you need, you can plan on spending a lot of time snooping at farm sales, or crouched over with welding equipment to adapt modern implements to a non-standard hitch. And remember that the tractor may be retired or traded before an implement has outlived its usefulness. If you have a flail mower that only fits a John Deere 400 garden tractor, you are going to need a new flail mower if you trade the tractor. The aftermarket for specialized implements fitted only to a single tractor is limited; three-point hitch implements are generally easy to sell or trade.

Not every implement attaches to a hitch at the back end of the tractor. Most garden tractors and the smaller utility tractors accept mowers on belly-mounts. A belly-mounted lawn mower is easier to maneuver than a mower towed behind on a three-point hitch, but if you have to remove the mower to use the tractor with other implements, it means crawling underneath -- with grease, mud and grass clippings falling on your face -- to unbolt or uncouple the mower, which then has to be dragged out from under the tractor.

Of course, there are tradeoffs. To mow along an edge with a belly-mount, you look down. Mow enough edges with a mower on a three-point hitch, and you begin to wish your head were screwed on backwards.

Front loaders, blades, and snow-blowers generally hook onto proprietary mounts. If you need to load barn scrapings into a manure spreader, there is no substitute for a front-loader, but you have a heavy implement which takes time to attach and remove, and which requires considerable ballast at the back of the tractor that must also be removed if you are going to use the tractor with other implements. If your need is for a loader to move material from the barnyard or compost heap to the garden, you may be able to get along with a scoop or loader mounted on the three-point hitch, which is substantially cheaper, easier to put on and off the tractor, and simpler to maintain. Some rear-loaders, such as the Westendorf Rear-Ender, use catches and chains through rollers on the drawbar to enable the three-point hitch to control a dumping action and a fixed scraping position. You have to get used to driving as much of the time in reverse as forward, but that's true of a front loader too, and rear-loaders require less ballasting to maintain the balance of the tractor. Rear blades can also be versatile. They usually lack the full hydraulic swiveling action of a front blade, but offer economy, ease of mounting and unmounting, and the convenience of being able to swivel three-hundred sixty degrees.

Most tractors large enough to have a hydraulic rockshaft also have a manifold or other take-off point for hydraulic power that can be run to a log-splitter, or through selective control valves to a front loader or blade. Some implements, like a backhoe, demand enough hydraulic capacity to require an auxiliary pump fitted to the PTO. If you are planning to add hydraulic implements, make sure the tractor hydraulics are compatible with the implements. The hydraulic systems on most garden tractors are only powerful enough to lift and lower a blade or mower; they do not have the power for a log splitter or a loader.

Hydrostatic drive is more than an automatic transmission. A hydrostatic drive allows you to control your speed and direction with a single dash-mounted lever, or a heel-toe pedal, and without using a clutch. Some buyers choose a hydrostatic transmission for small tractors on the grounds that it is easier to operate and will get the kids or a reluctant wife (or husband) onto the tractor. My own feeling is that hydrostatic transmission makes more sense for a tractor that is in constant use, like a commercial loader operator. For the relatively light duty of a non-commercial usage, especially if the tractor is used primarily for mowing and other chores that do not require frequent shifting, a manual transmission is cheaper, easier to maintain, less likely to overload, and does not suffer the loss of efficiency inherent in hydraulic pumps and motors (approximately twenty percent). Try to pull too hard with a manual transmission and you stall the engine. The same pull with a hydrostatic transmission could burn out expensive hydraulic seals.

If you choose a manual transmission, one good feature to look for if you are doing any loader work is a "shuttle" shift, which allows you to go from reverse to a moderate forward gear with a straightline shift. With a hydrostatic transmission, if the control is a heel-toe pedal, check for a manual lock for long stretches of mowing or transport, when you won't want to keep your foot on the pedal.

Power steering is frequently available on tractors as small as garden tractors and riding mowers. For constant use, such as commercial mowing, especially with tractors that are heavily loaded on the front wheels, power steering is an arm-saver. For intermittant use, many owners may prefer the precision of manual steering. When the turns are really tight, the differential brakes (independent brakes for each rear wheel, which can be locked together for over- the-road use) do as much of the turning as the wheel. One disadvantage of power steering on smaller tractors is that the tractor can be slower to warm up in the winter, because the additional hydraulic fluid has to be brought up to operating temperature before the tractor can be driven.

Four-wheel drive lets you scale the tractor down, using a smaller engine and smaller tractor, which is economical and easier to maneuver. When you need extra traction for occasional heavy hauling or tillage, you engage the four-wheel drive. Four-wheel drive tractors are also more stable, because they can have somewhat smaller rear wheels, larger front wheels, and a lower center of gravity, and because they can be ballasted with the weight more evenly split between front and rear wheels. The heavy loading over the rear wheels on a two-wheel drive tractor creates a tendency to do what kids on dirt bikes call "wheelies."

Another option to increase traction is a differential lock. The differential is the gearing which enables a vehicle to go around corners by permitting the rear wheels to turn at different speeds. The differential also lets one wheel spin in the mud or ice so that you get nowhere. The differential lock, usually a small pedal that you depress with your right heel, temporarily locks the two wheels in synchronization, increasing the traction until you get past the slippery spot. Most differential locks automatically release when the two wheels recover their normal traction. It is dangerous to drive around corners or on uneven terrain with the differential locked.

Small tractors are generally offered with a choice of agricultural ("bar") tires, or turf tires. The bar tires provide substantially better traction on soft ground, and are the choice if most of your work is plowing, loading in muddy or mucky areas, or pulling heavy loads in boggy ground. But those cleats which give such fabulous traction in the mud will tear up a lawn and make a mess of a pasture in the spring when you use the tractor to haul hay to stock or to spread lime or seed. "High-flotation" turf tires minimize damage to soft ground. You can improve the traction of turf tires by adding chains if you need double duty. Liquid fill for tires or removable ballast, either bolted onto the wheels or "suitcase" weights on brackets, can also be used to improve traction.

Choosing a tractor is like choosing a computer. With a computer, you decide what you want it for, select the software you will need, then choose a machine that will run that software. With a tractor, it makes sense to start with a list of what jobs have to get done, how often they need to be done, and how much tractor time they will take. Some jobs may be important enough to demand a dedicated implement. Others may be so occasional that you can rent equipment to do the job, or adapt implements that are less than ideal. Once you have a list of the implements that you need, figure out how big a tractor you need to use those implements on your place.

The trick in compiling a list is to put down the jobs that need to get done on your place, rather than the jobs that you fantacize by the fireside on winter nights. If you are sure that in a year or two you are going to plant six acres of corn on what is now a second-growth meadow, you may want a tractor big enough to pull a two-bottom plow. But if you buy a tractor too big or too unwieldy to pull a mower over the acre of lawn that has to be mowed every week, you may find that the tractor doesn't get much use, and that you need a riding mower in addition to the behemoth.

It is just as much a mistake to expect too much of a small tractor. You can buy plows and disc harrows and front loaders and even backhoes for garden tractors, but a garden tractor is primarily a lawn mowing machine. It will do a dandy job of mowing, pulling small carts, and plowing the snow off a driveway; once the land has been broken by a larger machine, a garden tractor with a rotary tiller will do a fine job of cultivating a large garden plot. But it cannot substitute for a general purpose or utility tractor for hauling, clipping overgrown brush, or heavy tillage.

A final consideration may influence your choice of a tractor. One of the pleasures of country living is the easy swap of tools and "custom" work. If one of your neighbors has a posthole auger that would be just right for fencing your meadow, that's not a bad reason to buy a tractor with a hitch and PTO that will fit the auger, especially if you also buy that lime spreader that is just what both of you need to renovate your pastures.

[This article was originally written for and published in part by Countryside Magazine in 1990]