The American Birkebeiner is the second largest cross-country skiing race in the world and is quite a big deal within that sport. At 55 kilometers it’s not a short event, either, requiring a significant amount of training to even complete, let alone perform well enough to be competitive. Around a decade ago, friends [Joe] and [Chris] ran afoul of the rules when [Joe] accidentally won the race wearing [Chris]’s assigned entry number, a technicality that resulted in both being banned from the race for two years. Now they’re back, having learned their lesson, and are strictly adhering to those rules this time using these tandem cross-country skis.
The idea for this build was to make sure they could both compete in the race and win because they’d compete in a category no one enters, mostly because it effectively didn’t exist before these two invented it. This required a custom set of skis, but since ski manufacturers don’t typically make skis for two people, they had to get creative. The duo picked up the longest pair of skis they could find at their local ski shop, moving the bindings forward on the skis to make room for the second set of bindings that were added to the back.
This presented a few unique challenges, the first of which is that cross-country skis typically use a special material on the bottom of the skis which grabs the snow to make uphill travel possible, and with the wider distribution of weight this material wasn’t functioning at peak efficiency. The other problem was the stress on the bindings caused by two riders, especially during a crash. This eventually resulted in a broken binding while [Joe] and [Chris] were training. They then upgraded to a more modern pair of skis rated for a single 269-pound rider, had the bindings fitted for two riders, and added a special grip tape over the larger area on the bottom of the ski.
After four months of training and getting in sync, the two were ready for the race. The results are covered in a second video linked below, and while neither of them won the overall race this time, they did finish the event with in-tact skis, first in the new “tandem” class, and completely within the bounds of the strict rules of the race as well. Although winter is winding down in the northern hemisphere, for any of our southern friends looking for some other things to do with an old set of skis for the upcoming winter season, take a look at this sled which adapts some alpine skis to achieve some extremely high speeds.
Continue reading “Hacking Skis, Rules, And Friendships” →
If you’re a fan of endurance racing motor vehicles, there’s one that puts the 24 Hours of Le Mans, the Dakar Rally, and the Baja 1000 to shame, and the race doesn’t even involve cars. Indeed, the vehicles used for this massive trek from France to China are electric bicycles, powered only by solar panels. This is the epic Sun Trip endurance race, and one of its competitors built a unique tandem bike that is powered both by pedaling, rowing, and the solar panels.
The tandem bike is interesting on its own since the atypical design uses a back-to-back layout which means one person is facing backward, but the storage space is dramatically increased over the normal forward-facing layout. The person in the rear doesn’t pedal, though. [Justin_le] built an upper-body-powered rowing station for that spot so that the person riding back there can rest their legs but still help propel the vehicle. Of course, there’s also a solar panel roof so the two riders can pedal and row in the shade, which includes MPPT and solar tracking which drives a small electric motor on board as well.
This race started in June but is still going on. There’s a live GPS feed so you can keep up with the teams, and if you get really inspired you can go ahead and sign up for the 2019 race as well. This particular bike was also featured on Radio Canada as well if you’d like to learn more about it.
Thanks to [Arthur] for the tip!
This project really puts an end to arguing over who has to ride in the back of the tandem bicycle. We challenge you not to smile while viewing the maiden voyage that [Carlos] and his daughter take on this side-by-side bicycle. The video can be found after the break.
It certainly makes a bit more sense than an over-under tandem, and the fabrication process is really quite manageable. This requires alterations to the seat, handle bars, and pedals, but the majority of the bike (frame, gearing, fork, wheels) is unaltered.
The cranks have been replaced by a custom welded cam mechanism that reminds us of how the pedals on a paddle boat work. Both riders must pedal at the same time and rate. To give each a place to sit the seat post was converted into a T bar to host saddles to the right and left of the frame. Finally, the handle bars are the most complicated of all. Extra framing was welded onto both sides for the front tube to provide a place to mount two pair of handle bars. One of them is fixed in place, the other can be turned, using a lever mechanism to steer the front fork.
It looks a bit awkward to get started, but once both riders are up it seems quite stable.
Continue reading “A Bicycle Built For… Siamese Twins?” →
Here’s an interesting way to fill the second seat on your tandem bicycle. It seems no one ever wants to be the stoker, so this gentleman decided to build his riding partner. JouleS powers the bicycle from the back using the same motions a human would. It’s not the easiest way to make an electric bicycle but the mechanics that went into it are quite beautiful. See the old boy pedaling away after the beak.
Continue reading “A Bicycle Build For… 2.0” →
We normally advocate wearing a helmet when biking in case you get hit by a car. In this case the guy on the bottom of this double-decker bicycle should wear a helmet to avoid a boot to the head. When we started watching the video after the break we thought that [James] had just built a really really high bike. Not the case, he built an over-under tandem bicycle. What’s more outrageous? Check out that killer kick-stand twenty seconds into the clip.
Continue reading “Another Take On A Bicycle Built For Two” →