ForConstructionPros.com

A trencher's job is obviously to dig a trench. How the machine gets that job done can happen in two ways: with a mechanical or a hydrostatic drive. In order to figure out which type of drive system is best for your rental business, you'll have to do a little digging.

Putting power to the ground

A mechanical drive system offers a simple design as well as a slight edge in productivity. The mechanical - or direct - drive system transfers horsepower from the engine directly to the digging chain. On a hydrostatic model, the power goes from the engine to the hydraulic pumps to the control valves then to the wheel and chain drive motors - losing efficiency.

In fact, it's estimated that hydrostatic drives offer roughly 85% of the efficiency of a direct drive. In other words, you'll get more productivity from a 10-hp mechanical trencher than a 10-hp hydrostatic unit.

There are trade-offs, however, for gaining that small bit of efficiency. Trenching by its nature is an aggressive application. Mechanical-drive trenchers have a lot of wear parts - including belts, pulleys and gearboxes - that need maintaining. Hydrostatic trenchers have less routine maintenance, which is always a benefit to rental businesses.

"There is less maintenance on a hydrostatic system - checking the hydraulic oil level daily is much easier then adjusting a drive belt or clutch on a frequent basis on mechanical units," says Jon Kuyers, utility products segment manager with Vermeer Corp.