There is only one round of the UCI DH World Cup left, and then we can begin the final countdown to World Championships, the biggest race of the year. An aura of mysticism surrounds it, this is a race where athletes are putting everything on the line, bare knees, single ply tyres or aluminium bolts. So far the top teams have engaged in eye-pleasing Paintjob warfare with Pitty and Bossman leading the way, but sometimes those unique conditions create new components and even frames, like the DaVinchi Sparthan.What if...
I told you that bike designers got so inspired by Aaron Gwin's chainless massacre
in Schladming, preceeded by Neko Mullaly's amazing run in Hafjell
, that they decided to play with the idea of a chainless DH bike. Which other track than Val Di Sole fits such bike better? Several journalists did real-life tests with and without a chain (Dirt, GMBN) and the results were quite shocking with lap times being within seconds. What are the potential benefits of running a bike without the drive train? Well for starters, the weight of the whole bike would go down by a full kilogram, and most importantly, the unsprung weight at the rear axle gets cut by at least 400g since we are getting rid of the rear derailleur, cassette, chain, and freehub body. If you think for a moment about how many rocks and roots of all sizes that heavy wheel has to ram into during the course of Val Di Sole or Andorra's track, this may mean shaving off whole seconds by just riding along. Removing chain tension makes it even easier for the suspension to take the wheel out of the way of obstacles. Chain growth becomes a non-issue and engineers can further optimize suspension kinematics. Finally, if we skip the crankset and the chain ring, the bottom bracket height can get lower by at least 5cm. This dramatically lowers the center of gravity of the bike, improving cornering and handling in general. Chainless Specific Downhill mountain bike:
Here is my go at the design of a chainless DH bike, the Formula 1 of push bikes. First up is Y-Me Industries with their Schmetterling, which means "Butterfly" in German. We all know who could pilot that thing to get the gold medal and the most prestigious pride-flag resembling jersey. The man in question is known for using very little of his suspension and I had the pleasure of watching him in person bounce off of the tops of fridge-sized boulders, hence the 650B wheels of the bike are mounted to only 150 millimeters of travel in the front and 160 in the rear. Geometry is not exactly a Geoshmetron, a 61-degree head angle and near 1300mm wheel base should please many keyboard warriors. The bike has a relatively long chainstay at 460mm. The suspension is based on a high pivot design with initial rearward axle path for ultimate smoothness and steady wheelbase change. Kinematics are built around a modern air shock, Faux X26.
The fork is a bit of an engineering beauty, the upside down design is for a bit of extra traction and supreme tracking through the race course from hell. 1.5 crown design to improve aerodynamics, reduces stress at the crown/steerer interface and maximum fore/aft stiffness under braking. The whole upper assembly is made of carbon fiber with two aluminium tubes cast inside, working as a sliding surface for the bushing mounted at the end of the inner legs. Thanks to using a carbon fibre monocoque structure and (actually) clamped 24mm axle Y-Me could manipulate stiffness of the fork the get the desired result. Yes, there is one bushing under the wiper seal and one at the end of the 35mm inner leg. This way the bushing offset increases with the travel, stiffening up the fork at the best possible moment and eliminating the issue of bending of the inner legs, which creates additional, unwanted resistance in standard forks featuring both bushings mounted in the outer leg assembly. Then we have the air spring with a high volume negative chamber and off course the tokens... made of fricking 26" carat gold. No... but the fork may have a twin tube damping cartridge in golden color from the Swedish Åhléns (read Oh-leans), of course with separate high and low-speed compression adjustments. The bike has quite a slack head angle to better work with angle of attack forces acting on the fork, therefore the fork offset has been set at only 44mm.
The bike features special pedals from HP, thanks to a slight drop of the axle they always remain with the right side up and provide a better platform to stand on when pumping. HP makes both a flat and clipless chainless specific pedals, or rather platforms.
Super Push Bike
The second bike could have been designed already, last year. Socialized's engineer, James Chamberlaine designed most of his favorite features into this bike, that is a very low center of mass, long front, shorter end, slack head angle and low BB. I am not keen at all to write more about it since I know that the Pinkbike audience always has a lot to say when a bike from this company comes along. I don't want to enrage the masters of numbers. So here it is; the Socialized X-Works HOTwalk F5R.
Could chainless bikes be the way forward? Could it be a new trend after this 120 hyatus or the Plus fuzz? Perhaps some rental park bikes could be designed as chainless, which could lower the prices of the rental? Joeys like me probably only pedal on the hips of the jumps when they roll on machine dug trails anyways. I'd like to say that I'd really love to see more genuinely interesting bikes being designed. The less bikes that look like a Seshion the better... because the Seshion is a damn good bike, but make your own good bike, damn it.
Wacek Kipszak – Waki@WAKIdesigns
/ Waki on Facebook
: This article is meant to be a satire. My very intention with it is to entertain you and eventually provide some food for reflection in case we treat our sport a bit too seriously. I honestly do not wish to insult or harm anyone or any company. Eventual resemblance to persons, names and places might be coincidental.