NAHBS 2012 – Priority Cycles’ Insane Dual Drive Carbon DH Bike Prototype

2012 NAHBS Priority Cycles carbon fiber DH mountain bike prototype for hippie tech suspension

Priority Cycles showed off quite a few full suspension bikes last year. For 2012, their booth was sparsely populated, but it had a real show stopper.

The prototype DH bike above was made for HippieTech suspension founder Jerry Vanderpool, who will be racing it all season, including at Sea Otter Classic, to test it. Then, Priority Cycles’ builder/owner Damon Madsen wants to put into production. It’s pure prototype, as you’ll see from the rough construction, but it’s totally sick. We’re talking dual drive inside the front triangle, left-hand belt drive and right-side rear disc brakes. Here’s how it works…

2012 NAHBS Priority Cycles carbon fiber DH mountain bike prototype for hippie tech suspension

Because the swingarm’s single pivot is so far forward, the rear wheel has a virtually vertical axle path. That allows room for a seatstay bridge with about 1.5″ of space left between the tire and seat tube at full compression.

2012 NAHBS Priority Cycles full suspension mountain bike

Design uses an Alfine 8-speed hub as the gear cluster with left side belt drive and full floating brake on the right. Took six months to build this first version.

2012 NAHBS Priority Cycles carbon fiber DH mountain bike prototype for hippie tech suspension

Has 8.25″ of travel, comparable to most World Cup-level DH bikes on the circuit. The suspension gets its leverage ratio via several links and arms. (A) connects the swingarm to a connection link, which contacts the shock linkage at (B). The shock link’s (or whatever you want to call it) main pivot is (C).

2012 NAHBS Priority Cycles carbon fiber DH mountain bike prototype for hippie tech suspension

2012 NAHBS Priority Cycles carbon fiber DH mountain bike prototype for hippie tech suspension

Belt is really loose to allow for chain growth, but it’s tight at full extension. Chain tensioner rollers on the front and rear cogs keep it in place. I love that they’re spaced using Avid’s CPS washers on the rear.

2012 NAHBS Priority Cycles mountain bike

Priority’s regular bikes have a redesigned linkage and swingarm to make it stiffer and give it a better shock curve. His designs use a 2:1 shock ratio. New carbon linkage came about because he was out of aluminum and had some carbon laying around.

2012 NAHBS Priority Cycles full suspension mountain bike

Comments

Ripnshread - 03/15/12 - 12:31pm

I think you meant (C) is the swingLINK’s main pivot?

ryan - 03/15/12 - 12:33pm

GT IT-1

http://bmxmuseum.com/bikes/gt_bicycles/21060

hope the belt stays on.

Kristibee - 03/15/12 - 12:39pm

Ripnshread, we fixed it.
Good catch, thanks.

craigsj - 03/15/12 - 12:45pm

That bike doesn’t have a “virtually vertical axle path”, it’s quite rearward. The belt idler pulleys are questionable. Gates specifically doesn’t allow them. It’s a hack, Zerode has done it all better.

Topmounter - 03/15/12 - 12:49pm

Beyond the additional complexity, what does this design do that other designs don’t?

Gillis - 03/15/12 - 12:52pm

That is some janky looking carbon. Not very reassuring on a bike let alone a dh bike.

Caseofthemondays - 03/15/12 - 1:07pm

@Gillis

Thats because Damon hand laid this carbon. If he had a mold built it would have cost over 50k easily. That’s not reasonable when you’re a small builder making a prototype frame on a small budget.

Personally, I was very impressed to learn the builder has a regular full time job and built this entirely in his free time after work.

I think the placement of that “floating disc brake” mount is a little questionable.

Steve M - 03/15/12 - 1:09pm

Where does the marble fall out? after the dominos fall or before the teeter totter?

dave - 03/15/12 - 2:28pm

I’m buying a life insurance policy on Jerry Vanderpool! Please post his contact info.

" Jumpin" Jerry Vanderpool - 03/15/12 - 2:38pm

Thanks Dave – You can contact me at http://www.hippietechsuspension.com for policy info !!

The actual pivot is at the bolt below B and C with the silver gaurd on it holding one of the pulley tensioners ! Axle path is rearward slightly than up ! Remember 20 years ago when Paul Turner showed the first Rockshox and people laughed – NOW LOOK at MTB Suspension !!!! HMMMMM

Damon’s design is SOUND and his bikes pedal and descend much better than anyone can Imagine !! That is why I ride his machines ! Once you ride one – YOU TOO WILL BE A BELIEVER !!

See it in action at Sea Otter soonest and more throughout the season

Jake - 03/15/12 - 2:41pm

Very interesting but I would have to agree with Topmounter.
One has to wonder about the cost / benefit is on this thing when compared to what’s out on the market already or perhaps, consider spending the money somewhere else on the bike other than the double drive thing-a-ma-bob.

Lawrence - 03/15/12 - 4:03pm

So – basically he took all the rear drive and brake components and reloacted them to the center triangle, thus centralizing the mass ?? And somewhere I remember reading about the benefits of reducing the “sprung” mass – thus making it easier to control wheel movement. Regardless of how it looks, the engineering principles seem solid. And any first iteration of something this different will look a little rough. But I’m sure interested to see how it works in a DH race. I love to see someone push the envelope lioke this. Who knows where it may lead?

Speedy - 03/15/12 - 4:52pm

Most of the commenters are thinking WAY to short term. People, innovation doesn’t come out over night, then drop in cost two days later. Sure, right now there are options on the market that may be a better value for most people, but for things to move forward we need people like this to create new, exciting, and interesting concepts. We need people like Jerry to ride them for us too. I applaud their efforts, even if it looks a bit rough at first, ya gotta start somewhere.

Topmounter - 03/15/12 - 5:52pm

I wasn’t even thinking of “cost”… just “what does this do that the other top designs don’t do?”.

Peter - 03/15/12 - 6:10pm

At NAHBS Jerry’s answer for “why this design” was that putting the Alfine hub smack in the middle of the bike reduced its moment of inertia – aka it should be more agile with the weight in the middle. Interesting idea, I don’t ride DH so I don’t know how much of a problem there is with a traditional drivetrain layout.

Steve M - 03/15/12 - 6:18pm

Sorry this thing does not hold water- No amount of pivots, shock rates, or floating brake gimmicks will overcome frictional losses in trying to pedal the beast.

Gillis - 03/15/12 - 7:30pm

@Speedy: other than using a belt drive (first one I’ve seen a on dh bike of any kind) there’s nothing innovative going on here that hasn’t already been tried in the last 10+ years. AND there’s nothing I see that has been improved upon to make those ideas more valid.

@caseofthemondays: I’ve seen hand laid carbon that wasn’t this messy. And the problem I see with it being this messy is that I see the possibility for voids and inconsistent wall thicknesses that could lead to failure.

S W - 03/15/12 - 9:26pm

As someone touched on, the point of this is that it reduces unsprung weight. The lighter the unsprung weight (tire, wheel, hub, etc.), the less force is required to get suspension moving… therefor the more responsive the suspension is to small bumps or other irregularities in the trail. More responsive means the wheel will stay connected to the ground more which leads to more traction.

There is obviously a trade-off. In reducing unsprung weight he has increased the total bike weight — probably substancially. That said, prototypes are generally ugly, heavy things that attract ridicule. I hope bike rumor does some follow up on this. Would be interesting to see where this goes.

Wil - 03/15/12 - 10:12pm

@Topmounter: With that attitude you should remind yourself that bicycles haven’t really changed in a 100+ years, they have only been refined. Dual trusses are so last century. As another poster has already stated Paul Turner (among many other cycling pioneers) were laughed at but continued to design and develop. To answer “what does this do that other bikes don’t do?”…I’d start by saying look at the photos and then ask, what are the other brands doing similar to each other AND how is it different then this.

David Willcox - 03/15/12 - 11:27pm

So essentially its a Zerode bike laid up in Carbon and using a belt drive? Just like all of Zerodes concepts.

http://www.zerode.co.nz/

gringo - 03/16/12 - 4:06am

Steve M: your marble comment has been voted by me as ‘Bike Rumor Comment Of The Year’. I’ll buy you a beer as your prize next time you are in TW.

Topmounter - 03/16/12 - 10:37am

@Wil: I’m not judging, just asking the question that wasn’t answered until Peter and S W’s comments. I never said or implied that “different just for the sake of being different” is not an acceptable answer.

joe T - 03/16/12 - 4:56pm

i sure miss Alex Morgan(BCD). anyone else?

travis - 03/26/12 - 6:15pm

I find it amazing that most people are so negative. Every one rips Specialized apart for going after the little guy and now everyone rips apart the little guy. Outside of Jerry and myself I don’t believe any one on this forum has ridden a bike by Damon. His designs are sound. He has been building bikes for years. Granted the carbon is not a clean as one we are used too but he does it completely by hand. Lets wait and see how Jerry does and see what changes he and Damon want to make after time in the saddle. Currently Damon has no big money behind him. He does this for the love of riding and building.

Dakota - 02/17/14 - 1:05am

I knew this concept of an internal rear hub in lieu of triple chain rings how about a NuVinci360 front and rear !?

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