Good grooming: the machines that make it possible.

You clip into your skis, step onto the freshly groomed trail and away you go, gliding across an immaculately prepared skate lane or classic track. We often take for granted the extensive preparations that make our skiing a fun and safe experience. Wonderfully groomed trails don't just appear overnight; there are no "grooming fairies." For the time and effort they put in, the dedication to excellence and their sheer perseverance in all kinds to conditions, the individuals who groom our trails deserve all enormous amount of credit and a daily pat on the back.

Groomers face a litany of challenges: not enough snow, too much snow, boiler-plate ice, freeze-thaw cycles, dirt, pine needles, leaves and sometimes even running water. While some are avid skiers who have a vested interest in their efforts, others are skilled equipment operators who take pride in producing a quality product. Regardless of who they are, however, they would be helpless were it not for all increasingly sophisticated array of grooming equipment at their disposal.

In Cross Country Skier, November 2001, we examined some techniques and methods used to groom cross country ski trails. Now, we turn our attention to the hardware that transforms "raw" snow into groomed trail. We hope the more you know about the subtle nuances of proper ski trail preparation, the more aware and appreciative you will be of the magic creating our ski trails.

Grooming relies on two primary pieces of equipment: the powered machines moving over the trails and the attached implements actually "grooming" the snow. Of the two work horses pulling implements, snowcats groom larger trails while snowmobiles most frequently cover narrower trails or work on inadequate snow to support a snowcat.

Snowcats

First employed for grooming and travel at downhill ski areas, snowcats brought sheer weight, stability and power permitting access up and down steep slopes. The larger, "caterpillar-style" tracks not only provided dependable traction, they also facilitated flotation through very deep snow. Alpine snowcat technology has carried over to Nordic grooming with the very same machines often used on cross country trails. However, smaller, more slender models are more appropriate for some narrower trails.

From farm tractors to road construction equipment, heavy equipment has evolved to an incredibly sophisticated level in part to produce a better end-product, but also to offer greater operational ease and operator comfort. Maneuvering in deep snow and over difficult terrain, snowcats, usually diesel-powered, also have the horsepower and torque to control adjunct equipment--power tillers and multiple tracksetters, via hydraulic connections that greatly increase the ease and quality of grooming. Moreover, system designs and power also result in faster grooming. Of the several snowcat grooming machine makes and models, only a few brands, however, have fallen into common use on cross country trails.

A frequently seen snowcat on cross country ski trails, Kassbohrer's PistenBully first hit the slopes in 1969. These revolutionary "full-sized" groomers designed to condition snow on Alpine downhill ski slopes featured diesel engines and hydrostatic transmission with automotive style controls (steering wheel).

With a working width from 3.6 meters up to 4.2 meters, the PistenBully crossed over to preparing Nordic ski trails. Later, two smaller width PistenBullys were developed with working widths of 2.2 and 2.5 meters.

Canadian-based Bombardier, another major player in the snowcat groomer business, manufactures models employed for cross country trail grooming across the U.S. and Canada.

The day to day working environment for a snowcat presents several challenges. Since the machine must be light enough to float on the snow's surface, specific ground pressure must be kept below one pound per square inch (psi). Overall vehicle weight and flotation provided by the tracks regulate ground pressure. Typically, the wider the track, the greater the floatation.

While a snowcat must be light enough for flotation, at the same time it must be constructed heavy and strong enough to plow snow as well as pull a working attachment. In addition, because snow deceptively transforms in freeze-thaw cycles or becomes severely compacted by high skier traffic, significant horsepower is required to properly recondition a compacted skiing surface.

A snowcat's main frame is mounted on support axles that act as the vehicle's suspension mechanism, the front axle also tensioning the tracks. Pneumatic or solid rubber 12-to 14-inch diameter running wheels act as guides for the track, which is powered by a toothed drive wheel--called a sprocket--mounted on a gearbox fixed to the rear of the main chassis. Two independently controlled …