02. September 2021

Optimized for load capacity: Snow groomer winch ropes in use

Only as thick as a ballpoint pen in diameter, they carry the full weight of a snow groomer on a steep slope. Snow groomer winch ropes are the tough workhorses in the wide range of ropes at Jakob Rope Systems. Their special design gives the ropes maximum load-bearing capacity and smooth running characteristics. Jakob rope experts Konstantin Kühner and Marcel Meier talk in this interview.

What do snow groomers do in operation today?
Konstantin Kühner: Every day after the end of ski slope operation, when the lifts are at a standstill, the work of the snow groomers begins. Often in the dark and at high sub-zero temperatures. They then start to re-prepare the slopes. This is done from the valley level up to around 3,000 meters above sea level in the highest areas of the ski resort. The vehicles have to cope with almost any terrain, even on extremely steep slopes.

Why do you need slope winch ropes for this?
Konstantin Kühner: A piste winch rope is used to secure the snow groomer on steep slopes. This allows the vehicles to prepare the ski slopes while hanging on the rope. For the driver, it is important that he notices as little as possible of the rope. He needs the safety, but must be able to move as freely as possible. The rope must not be too heavy or too elastic. It must not get caught on the ground. All this would interfere with the driving behavior of the snow groomer.

Marcel Meier: In contrast to the past, steep slopes can now be groomed from the bottom up thanks to the use of Snow groomer winch ropes and winches. This significantly improves the quality of the slopes, because the support of the winch means that the tracks from the snow groomer scrape up the snow less. In addition, the snow is pressed against the slope by the snow groomer when it is driven up. Bringing up snow that is transported downhill by skiers during the day can also be accomplished by using the rope and winch, so that exposed areas on the slope can be skied again without problems the next day.

So slope winch ropes have to perform a lot in the field.
Konstantin Kühner: These are robust high-end ropes that have to function as safely and with as little maintenance as possible, and over a great length. About 1050 meters of rope fit on the winch of a snow groomer. The long winch rope is wound onto a drum. It has to withstand this load case. The rope must be extremely wear-resistant. When used in the terrain, it is subjected to scratches, pressure and bending. This means: maximum breaking strength and transverse stability on the thinnest possible rope diameter. The more stability the rope offers, the steeper and faster the driver can drive his vehicle. And the heavier and wider the vehicle can be.

What are the differences between snow groomer winch ropes and other hauling ropes?
Konstantin Kühner:  Snow groomer winch ropes are specially constructed. The strands and the steel core inside the rope are layed double-parallel. This results in very high compaction and optimum force distribution in the rope. This special construction gives the rope its great stability and breaking strength. On the outside, the rope is smoother than other ropes due to its compaction. Thus it runs smoothly on the winch. Imagine your ballpoint pen. That's how thick a snow groomer winch rope is - 10 to 11 millimeters. The entire snow groomer hangs from it and descends 800 meters down the steep slope. So everything here has to be optimized for load-bearing capacity.

Which snow groomer winch ropes does Jakob Rope Systems offer?
Marcel Meier: We offer three types of slope winch ropes – all for retrofitting to Kässbohrer and Prinoth vehicles. Our Winch King 9 as a 9-strand special rope with a diameter of 11 millimeters is optimized for the capstan winches of Kässbohrer vehicles. And our Winch Power 8 as an 8-strand special rope with a diameter of 10 or 11 millimeters is used on the drum winches of Prinoth vehicles.

Have snow groomer winch ropes changed over the last few years? What trends are emerging?
Marcel Meier: Manufacturers are working on further increasing the breaking strength of ropes. That is certainly a trend. Our partner in Germany is currently testing a development in which slope winch ropes are given an intermediate layer of plastic. This fills out the rope optimally. Elongation is reduced, the rope can absorb even more transverse pressure, and the soft plastic bedding between the strands distributes pressure much better in the rope.

How can a customer recognize a good quality rope?
Marcel Meier: The production quality becomes apparent in the first operating hours when the new rope is in place: Does the rope remain stable, without twists and without deformations? If so, the quality is good. After that, snow groomer winch ropes are put through their paces in the field. In terms of quality, it is difficult to speak of a good or bad service life in hours. The snow groomer driver, the terrain, obstacles, visibility and everything that happens on the slope have an enormous influence on the service life of the rope.

Are there any maintenance tips that will prolong the life of a snow groomer winch rope?
Marcel Meier: If the visual inspection reveals isolated wire breaks, they may be broken out, otherwise the piece of metal on the drum may pinch off other wires sharply. After a certain number of operating hours, the rope can be completely unwound, a piece cut off at the rear end, and then rewound. This so-called back-end-cutting shifts the constant layer change point when winding and unwinding the rope on the drum of the snow groomer during further use.

Does Jakob offer other services about slope winch ropes?
Marcel Meier: We accompany our customers throughout the entire service life of their ropes. Jakob advises on all questions regarding the purchase, use and also the condition or damage of existing ropes. Our customers can send us photos or material at any time. We then assess it at the factory and provide feedback. On request, we also offer training on the use of snow groomer winch ropes.

What is the current situation regarding the availability of snow groomer winch ropes?
Marcel Meier: We recommend our customers to check and replenish their stock early for the coming winter season. Jakob has all three rope types in stock and our partner ensures sufficient supplies. We deliver very quickly from our locations to ski resorts in Germany, Austria and Switzerland. And also in the current winter season we strive for short delivery times. This means that we are quickly available for many ski resorts in an emergency.

(This interview is also published in: SI Magazin Schweiz Spezial 2021)