When shopping for a tractor, you have many features and options to analyze. Among the most significant is whether to choose a hydrostatic transmission or a manual gear transmission. A simple definition of a hydrostatic transmission is one that’s powered by hydraulic fluid and allows for seamless adjustment of tractor speed without changing gears. A tractor with such a transmission can be easier to drive and control.
Given that, a hydrostatic transmission might seem like the easy winner, and indeed, it probably is the best choice for many hobby farmers. Hydrostatic transmissions offer versatility and ease of use. Why would you ever want a gear transmission?
But for certain tasks, and in certain circumstances, gear transmissions are a great choice. Let’s examine the pros and cons of each.
How They Work
A hydrostatic transmission uses hydraulic fluid and a variable displacement pump to drive a hydraulic motor. The transmission may or may not be user-serviceable, because it’s important to keep the system clean and free of contaminants.
The primary benefit here is ease of use. Hydrostatic transmissions are controlled by pedals (forward and reverse), with a wide array of increments in the overall range of speed. The ability to instantly shift from forward to reverse makes hydrostatic transmissions the preferred choice for performing work with front-end loaders, such as moving manure or compost. The ability to control the speed and direction of travel with your foot is another positive, freeing up your hands to focus on steering and operating the loader.
Hydrostatic transmissions are not as efficient as gear transmissions at translating engine horsepower into power take-off, or PTO, horsepower. So if you use PTO-driven implements, double-check that the PTO horsepower of a tractor with hydrostatic transmission is strong enough to handle the tasks. These transmissions are also considered a little less suitable for handling sloping terrain.
How They Work
A gear transmission uses a gearbox to change the tractor’s speed and direction of travel. The complexity and quality of gearboxes varies widely. In essence, though, a certain number of forward speeds plus reverse is available, and the operator is required to depress the clutch to change gears.
For high-level farming tasks that require maintaining a very specific speed (tilling, seeding and so on), gear transmissions are still a great option. With a gear transmission, you can choose a gear and lock the tractor to one speed. Gear transmissions are also considered superior for negotiating sloping terrain—going up and down hills—and they translate more engine horsepower into PTO horsepower.
There are many types of gear transmissions. Some offer more versatility and ease of use than others. Nonetheless, they’re more complicated to use than a hydrostatic transmission. In most cases, you must depress the clutch to change gears or to change from moving forward to reverse and vice versa. This reduces efficiency for tasks that require constant changes in speed and direction, such as operating a front-end loader.
For a typical hobby farmer pursuing a wide variety of small-scale tasks (particularly those involving a front-end loader) a hydrostatic transmission is clearly the best choice. But if you farm on a bigger scale and plant large fields of crops, or if your farmland is particularly hilly and challenging to negotiate, then a gear transmission might be the best option.