ski technology new solutions to old problems

Unfortunately, one of the snow banks ended too early and Jimmy came flying by me in the air while doing a perfect somersault. He landed in a huge snowdrift totally undamaged. The left ski had caught a tree and Jimmy decided to jump off. So, how did he manage to perform a somersault? When you jump, you don't let go of the handlebars right away and that pivots your legs up, was his explanation. That way you don't catch your knees on the bars and break something. I thought it was some kind of test driver trick developed through years of breaking prototype sleds, but later found out he is a black belt in Judo and knew how to get thrown. Fortunately, the damage to the left ski was not bad and we could continue our trip. The incident, however, did leave me skeptical about twin runner skis.

That brings us forward from that early MX to Ski-Doo's REV MXZ. Last winter I rode a Ski-Doo REV with twin runner skis and was positively impressed. The REV handled great in all the trail conditions we encountered at our new machine tests. Twenty years have gone by and sleds are a lot different now.

With the new driver forward position, there is more weight on the skis. An aggressive single keel ski is harder to steer and gives too much handlebar feedback in regular trail conditions, although single keels still are used on Ski-Doo racers. The second large difference is the new "coupled" suspension, which reduces front-end lift and keeps the skis planted on the ground. The REV had such excellent handling and steering; I had to double-check and see if it really had twin runner skis. With typical 20/20 hindsight, I've re-thought the MX we rode in the 1980s and feel it was actually way ahead of its time. It may only have lacked "coupling" of its long travel rear suspension to make it acceptable.

Ski Doo claims that twin runner skis reduce "darting" on the trail and therefore are safer and easier to run. With a single runner, the carbide will fall into a groove made by a previous carbide runner. This will force your ski to follow the groove and dart your front end around accordingly. With two runners, the other runner will hold the first one up off the groove and prevent it from forcing your steering into the darting mode. Unless of course, both runners fall into equally spaced grooves.

The probability of falling into two grooves at the same time is fairly small, while one runner by itself usually will find a groove to follow. If the twin runners prevent darting, how about mounting them on conventional single keel skis? One of the first to grab this concept was Woody's, the after-market traction and control manufacturer. They introduced twin runners mounted on a plate, which in turn could be installed on a conventional single keel ski.