DETAILS THAT MAKE V2 ROLLER SKIS DIFFERENT
U shaped Aluminum Forks: The third generation forks have a geometry, which virtually eliminates areas of high stress. All intersections have generous radii, which reduce stress concentrations. The cold forged ribs on the forks increase the torsional rigidity and forging also makes the metal itself stronger. All V2 forks are made in a monolithic U shape, which makes them stronger than if the left and right forks are singular units mounted to the shaft. On aluminum shafts the forks are welded to the shaft, which is one of the strongest methods of securing aluminum to aluminum.
On the composite shafts the forks are designed so that the shaft fits very tightly in the U shaped fork. Just like in the riveting of precision components, the holes in the shaft are drilled after the shaft and fork have been mounted. When the holes are pre drilled prior to assembly the holes in the fork and shaft must be larger than the diameter of the bolt. Even with very tight machine positioning tolerances the holes would have to be much larger than the bolt. By drilling after assembly the holes are precisely the diameter of the retaining bolt providing the best possible mechanical retention. In addition to the bolts a bonding agent is applied to the inside of the fork.
U shaped forks are designed to protect the shaft. On V2 roller skis we rarely see damaged shafts. On V2 skis that have been used by novice skiers, who have not yet learned to skate properly we see the damage on the forks, not the shaft. The U shaped forks are particularly important in protecting the carbon composite shafts.
Composite shafts: Every skier and coach that has contacted us has said that on paved surfaces the XL98R skate skis and the XLC900 classic skis provide the most snow like feel of any roller ski on the market.
The light / weight core is wrapped with unidirectional and biaxial carbon and is infused with the most advanced epoxy available. In addition to the protection of the U shaped forks the composite is encased in a 0.25 mm thick polymer, which also acts as UV protection for the carbon. ( The manufacturing process for the shafts was developed by Jenex.) This is a true carbon composite, not a wood composite with glass or carbon fiber added for reinforcement. The XL98R weigh substantially less than wood based composite 100 X 24 mm wheel skate skis.
Lower Center of Gravity: Because carbon is extremely strong and stiff, compared to aluminum or wood, the V2 composite shafts can be made thinner than the shafts on other skis. A number of skiers, including coach Sten Fjeldheim, have commented on the stability of the XL98R and XLC900 roller skis. The reason the skis are more stable than other skis is that the top of the shaft is about 18% closer to the center of the wheel than V2 aluminum shaft or competitors wooden based skis. Eighteen percent is a significant number. Because of the camber in the V2 composite shafts there is actually more ground clearance for the shaft than in the aluminum versions.
Wheel Alignment: Most of us are not anatomically balanced, so even though the wheels and bindings are perfectly aligned, the ski might pull in one direction. Most roller ski manufacturers provide no method for wheel alignment. Some manufacturers suggest that you to bend the fork if the ski pulls to the right or left. Our unique wheel alignment device, available on all XL models, makes it very easy to change the tracking. Simply draw a pencil line along the side of the lever, loosen the nut slightly and if the ski pulls to the right move the lever forward and if the ski pulls to the left move the lever backward. It’s simple and it works.
Rolling Resistance of Wheels: The rolling resistance of tires is a function of the amount of energy the tire absorbs. A fast tire absorbs very little energy and uses a “high rebound” rubber. A slow tire absorbs a lot of energy. This energy turns into heat. If the rubber composition is used to absorb the energy the tire can become so hot that it can disintegrate in just a few hours of roller skiing. The tire fails just like the truck tires you see lying on the road on a hot day.
Jenex no longer uses any high / energy absorption rubber. On the W98RS, the slow wheel on the XL98RS skate ski, we use the same rubber composition as on the W98RM, but slow the wheel down with a recently patent approved lightweight (10 gram ) internal speed reducer called the ISR. The ISR is exactly the size of a 22 mm bearing and on the slow wheels we simply increase the depth of the bearing bore to accept both the ISR and the bearing. The ISR has two elastic sealing lips that rotate around a very precise hardened steel spindle. Between the two sealing wipers is a high viscosity lubricating fluid. This system increases the rolling resistance by about 15 / 20 %. The heat generated by the shear action of the fluid is dissipated through the aluminum bearing tube and the aluminum bolt. Aluminum is one the best heat conducting alloys so the aluminum forks act as a heat sink. Without using the high / energy absorption rubber we can obtain three different wheel speeds. With four W98RM wheels we have a medium speed ski, with four W98RS wheels we have a slow ski and with one W98RM and one W98RS mounted on each ski we have a medium slow ski.
Bearings: If you spin a wheel on an in line skate or roller ski with bearings that are lubricated with light oil and are not equipped with contact seals, the wheel can spin for several minutes, while contact sealed bearings with grease lubrication will stop in a few seconds. The conclusion that most will reach is that the free spinning bearings will make the wheels substantially faster. Wrong! In order to accurately test the rolling resistance of the wheel, the wheel must be under similar load as when the roller ski is being used. Jenex has developed a test machine that accurately measures the rolling resistance of wheels under load. The wheels are driven at a constant speed of 30 kilometers per hour. The machine works just like the cruise control on a car. As you encounter a hill more gas is supplied to the engine to maintain the speed. Our engine is a precise electric motor and we measure the current required to keep the wheel speed at 30 kilometers per hour. The energy required to maintain the speed is measured in milli ampere so the test machine is extremely accurate. We have found that, under load, the non / sealed oil lubricated bearings are only slightly faster than permanently sealed greased bearings.
Forged Aluminum bolts: To further reduce the weight of our roller skis we use custom made 7075-T6 aluminum bolts. These bolts are very strong and almost three times lighter than steel bolts. Aluminum bolts can only be used on free wheels as the extreme torque required to lock the needle / bearing clutch requires heat treated grade 12 bolts. For the clutch wheels we use aircraft grade 12-9 bolts.
Kinematic Dampened Classic wheels: The W10, W20 and W30 wheels all use the same hub and the same rubber. To increase the rolling resistance we use a Jenex patented kinematic damping system. It’s similar in principle to the ISR in that we use the shear force of a stable high viscosity fluid to increase the rolling resistance. When we developed the kinematic damping system in the early 90’s the components used in the more sophisticated ISR were not available.
Speed Reducers: V2 roller skis have become famous for the patented Speed Reducers, which were first introduced on the 900 and 800 series. Over the years the concept has been modified and improved numerous times. The latest generation Speed reducers work so well that you can ski in almost any terrain.
Brakes: Our first brake, introduced in the mid 90’s, was not an elegant solution. However, in 2005 we developed a revolutionary brake that really works. In 2007 we introduced an improved version for all XL model skis. By mounting the brake to the wheel fork we were able to eliminate several parts and make the system both stronger and lighter than the Universal unit. (A Patent for the brake system was granted by the US Patent Office in 2010.)
Aluminum Wheel Hubs: Our newest models, the XL9848 and the XL98R use an advanced custom hub extrusion. We began the tooling for this extrusion in 2009 and we received the first wheels in the spring of 2010. This is a symmetrical spoke hub that is similar to the hub on a competitor’s skis. However, if you look carefully you can see the difference that makes our hub, and wheels, lighter. The XL9848 wheel hubs are machined in such a manner that we can also insert the patented ISR as well as the one / way clutch housing.
Aero Roller skis: In the summer of 1999 we introduced the first pneumatic tire roller skis that actually worked. (Another manufacturer had introduced pneumatic tires earlier, but due to many problems the line was discontinued.) The Aero roller skis have become very popular and over the years we have made many improvements. With the Aero you can roller ski on both paved and non / paved roads. Since the Aero will roll over objects and cracks in the pavement that stop other roller skis most skiers consider the Aero safer. Many users have told us they spend a lot more time roller skiing on the Aero than they do skiing on snow and many have also told us that without the security of the Aero they would not roller ski.