New test method will create fair competitions on roller skis

The Swedish Ski Association’s recommendation for competition skiers in roller skis has been: The reels’ resistance should correspond to cross -country ski friction against the snow in longitudinal tracks. The problem: Different ski brands with « Standard Wheel 2 » have rolled with different resistance.

At JSM in roller skating last year, four students at Chalmers University University in Gothenburg measured 62 skis. The answer was that it separated just over three minutes between the best and worst ski – a difference corresponding to first and eighth place.

– Roller skiing becomes a material sport. The ideal is that competitions should be decided by athletic abilities such as oxygen uptake and riding technology rather than by the equipment’s technical qualities, says Andréas Löfgren, a civil engineering student at the Department of Micro -Technology and Nanoscience, which has led the project.

A measurement method and A measuring instrument that the students developed can now make the competition terms more justice.

To explain, he begins by describing the classic method to measure a ski rolling friction. A dynamometer that is stuck in a wall is stuck on a rider with roller skis. When the rider is gaining momentum on a roller conveyor, the dynamometer will measure the internal pulling force of the wheels. The ratio between the pulling force and the field’s gravitational force creates what is called the ski rolling friction coefficient.

A method with many practical restrictions. On the one hand, the roller band is huge, expensive and cannot be transported. On the one hand, each individual test takes a long time and requires a human rider and manual calculations.

– With the new technology you just mount a ski in the instrument and press Play, so you get a roller friction coefficient on a display. It can be done by anyone anywhere, says Andréas Löfgren.

The Swedish Ski Association has been involved in the project. Ludvig Remb is a competition coordinator for roller skis at the union and tells DN that lightly rolled wheels can give a very large competitive advantage – that the difference is greater compared to various good chosen skis on snow.

Based on the tests that the union did with the students last fall, the list of approved wheels has now been updated. A own test machine should be purchased and the plan is for ski producers to be able to submit their wheels for classification. The idea is to create three to four different classes with different rolling resistance and that competition organizers should be able to say « Today we run on Wheel Class 3 ».

Everything is in the starting pits, but the hope is, perhaps another season ahead, to be able to launch the test method even outside Sweden and thus get to an international standard.

Is this in demand by the riders?

– Yes. The big problem has been that an organizer needed a supplier who has come with loan skis to all competitors. If everything falls into place you will soon be able to have your own equipment and we will still have fair competitions.

– There is also another parameter worth mentioning, that it can be an important tool for training. Because sometimes the riders want more crisp to train certain characteristics – and vice versa.

REMB sounds more than satisfied with the opportunities for which the research project opened up. Understandable when you hear Andréas Löfgren describe one of the union’s test methods used to compare with the students’ measuring instruments.

– Two people put on skis, find one a small hill, hold each other for a while so that they have steady speed and then they release each other and see who rolls the longest. The problem from a technical perspective is that you really need to know the exact height and slope on the hill to get it standard.

In addition, the people are not exactly identical either.

– Exactly, all these disturbance moments come from with the instrument.