Something Different: Redalp's Downhill Bike

Here's an interesting one that found its way into our inbox this morning. Redalp was founded less than a year ago in Switzerland, and today they're launching this downhill bike.

The boys over at Redalp say that their patented articulated chain link allowed them to go a different way with frame design. Note the link attaching the upper chain pulley to the swingarm. This configuration has a very rearward axle path, more-so than just about any other bike we've ever seen.

Features:

What makes this bike interesting is the super high pivot and the chain mechanism. Curous about what they had going on, we pulled this from their website:

Background  - Since Henry John Lawson invented the chain for bicycles in 1879, this device survived all technical evolution and is still the most common drive train for bicycles. No other solution is as simple, reliable, lightweight and almost maintenance free as a chain. The pedaling power is not wasted and more than 97% is transmitted to the rear wheel. Even in wet or muddy conditions a chain works sufficiently well. Therefore most Mountain Bike manufacturers consider a chain the most appropriate drive train for their bikes.

When in the early 80’s suspension travel significantly grew, engineers were faced with a new problem, the problem of the chain growth. They realized that the pivot point location can’t be chosen for optimal suspension travel but is constraint to the upper chain line in order to avoid chain growth. Whether it is a virtual pivot point (VPP) or physical pivot point, the location needs to remain low. A low pivot point slows down the bike riding over rocky sections or roots, stresses the rear triangle and the rider does not feel comfortable or can crash. Creativity was required from all the different bike designers around the world.

Trend - It is possible to move up the pivot to a certain point, as long as the rear derailleur is able to compensate. For more innovative bike manufacturers that was not enough and they put the pivot point even higher. Trek, Ellsworth, Corsair, Morewood, BM, 2Stage and many others moved up so high, so that a jockey wheel for the chain became a requirement. Fantastic working rear wheel suspension was achieved but another problem came up, the problem of squat. We all know this embarrassing rear suspension movement while the rider is pedaling hard. Instead of pushing the bike forward, a lot of energy goes into the suspension. Therefore many bike manufacturers came back to the original design and to a low pivot point were the pedaling does not affect the shock absorber but on the other hand a ‘hard’ and inefficient suspension results.

Solutions - The Swiss Mountain Bike manufacturer Redalp went one step further and opened a new era in bike drive train technology. Redalp engineers put the pivot point higher to its optimal location for best rear suspension travel and solved the problem of chain growth and squat with an articulated jockey wheel. The pivot point became located right between the head tube and the rear wheel axel. A straight frame design saves weight, cost and is at the same time more rigid than a traditional frame.


Redalp's flagship Replica DH bike comes with a Fox 40, UST compatible Deemax and a 10 speed cassette. The Team DH bike is equipped with Easton Havoc UST wheels, a 10 speed cassette and a Boxxer R2C2. Visitredalp.com for more information.

What do you think? Is Redalp onto something with this design?

C50_89625830_1267691215 bturman 7/20/2012 4:51 PM

21 comments newest first

Are you kidding me? Disgusting. Looks like circa mid 90's on a track like Cap D'ai.
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I like the high pivot and new chain technology. But they have a lot of work to do in the styling department. The best bike in the world won't sell if it doesn't look good. I'd stick with a Zerode for now.
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YoYo
I can't believe the seat tube like that ... I'm not sure buying a Thompson and cut it out
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How do rearward axle path and no chain growth go together without the BB moving rearward too? Chain growth is change in the distance between the BB and the rear axle across suspension actuation, no?
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No, it's the difference in the length of the chain between the cassette and the crank sprocket. They vary that length with the pulley, they take out the 'slack' at no travel, and 'give it back' through the travel.

And you can easily have a reaward travel path with no chain growth, you just need a pivot-mounted gearbox!
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Well, reaward travel path implies a high gearbox location. Which also implies two chains. But yes, you are right :D
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Rearward travel doesn't imply gearbox to me at all. More bikes with idlers or Jackshafts and high pivots than gearboxs. I can think of about ten high pivots with idler, and only a half that with gearboxs. Also more with one chain than two tat I can think of. ;P
To the OP, by having the driving part of the chain go over a sprocket/jockey wheel/idler wheel near the pivots location, the designer can cancel any chain growth, or add a touch for anti squat when pedaling.
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YoYo well i was talking about gearboxes in the firstplace, that's wy i said it implies. Yes, there are more idler bikes than gearbox bikes out there, but mainly coz there are not that many gearboxes out there. But if you're gonna go through the trouble of idlers, high pivots, etc., why not just use a gearbox? With an idler and a REALLY high pivot, you still have a chain growth problem, you could end up having to use a long cage derailleur, because the lower part of the chain, that does not have an idler, get streched too. Not so with a two chain setup.
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I like it. Not sure how stiff she'd be, but I dig the adjustable anti squat, chain stay length, BB height, and head angle. Would pedal really well, with the least BOB ever. and would eat anything in it's path. Wouldn't swap my Zerode for it, but would be a great bike to have in the quiver. hunt down some super Monsters and tear any mountain a new arse hole.
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Wow, it's quite a week of hideous bikes. First the Mondraker Forward Geometry concept, now this...

No sir, I don't like it. Not one bit.
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Boombike75
tstep
sweet, lets throw most of the weight up high and give it an axle 29 inches off the ground so it jumps like shit. Better hope where you ride it is all rocks and roots
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socnick