SOC13: Devise Cycles’ Radical Adaptrac Equipped Zeppelin Fatbike

Adaptrac Zepplin

If you’re unfamiliar with Adaptrac, just imagine riding your bike and being able to instantly change your tire pressure, as you ride, without ever getting out a pump. Crazy, right? Just over a year ago, Adaptrac launched their on board tire pressure management system at Sea Otter. This year, to show off Adaptrac’s possibilities for the fatbike world, Brandt Weibezahn who is the man behind both Adaptrac and Devise Cycles, decided to build a wild full suspension fatbike complete with a linear suspension design, built in c02 expansion chamber, and a custom Maverick fork.

We get a closer look at the Zeppelin after the break.

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At the heart of the Zeppelin is the reason for building it in the first place – the Adaptrac tire pressure management system. Since the Zeppelin was built to use the system specifically, Brandt decided to build a custom frame that would utilize a sealed downtube as an expansion chamber for the c02 used to inflate the tires. C02 is stored in the bottle mounted to the downtube then allowed to flow into the tube of the bike where it expands and is allowed to come up to ambient temperature, and from there flows into regulator and switches mounted to the bars.

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While standard Maverick forks have been used for fatbikes with smaller tires and rims, Brandt wanted to be able to use a full size fatbike wheel and tire so he chopped up a Maverick to make it work. The new fork, named the Dinner Fork features custom triple clamps to mount to fork tubes which was no small feat since the lower Maverick clamps are actually welded on. Each tube had to be carefully machined down to precise dimensions to allow for the custom lower clamp which is just one example of some amazing machining displayed on the Zeppelin. Since custom clamps were already being made, the upper was designed to incorporate pressure gauges for each tire to see what pressure you’re running.

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Of course if you space out the fork legs, you’ll have to make a wider hub as well which is exactly what they did. The new hub is 135mm wide, still using Maverick’s 24mm thru axle design, with an offset hub body that allows the in-line to enter the axle on the outside of the hub, and the out-line exits hub center. The configuration of the hoses permanently connected to the valve stem is what allows for inflation on the go.

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The rear is a 170mm wide symmetrical thru axle hub with the co2 line entering the drive side of the axle.

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When asked about the linear rear suspension that rides on a a Cane Creek Double Barrel coil rear shock mounted inline with the seat tube, Brant says it was something he always wanted to try. The entire rear swingarm slides up and down on the two shafts mounted on either side of the shock thanks to recirculating ball bearings. The upper shock mount is attached to the front triangle, and the bottom shock mount is attached to the swingarm, while the glide rods hold the front triangle together. Due to the angle of the rear suspension and the front fork, the front and rear tireĀ  have the exact same axle path. If nothing else it is a feat of machining and fabrication just to make it work.

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Custom parts were all over the place on the Zeppelin. While XX1 fatbike cranks are coming, in the mean time if you want one on your bike you’ll have to get creative like Brandt. A standard XX1 crank was cut, surface ground, and then extended and machined to make a 100mm wide crank for the Zeppelin.

 

Comments

Matt - 05/03/13 - 9:48am

This thing is very cool. Way out of the box, and I like that. The one miss is the pressure gauges really should be at a lower range. Otherwise KILLER dream machine.

nanci djreaux - 05/03/13 - 10:47am

simple problems solved with simple solutions… wait, wut

Greene - 05/03/13 - 11:30am

Wait, “recirculating ball bearings?” what?

caliente - 05/03/13 - 11:50am

Looks AWESOME. I want to see a vid of someone SHREDDING on it though.

Almon - 05/03/13 - 12:01pm

Sweet!

Steve M - 05/03/13 - 12:46pm

Love it, dont think it want to pedal it. Weight?

satisFACTORYrider - 05/03/13 - 1:06pm

wanna demo that.

jimmythefly - 05/03/13 - 2:52pm

@ Greene, these:

http://www.sdp-si.com/web/images/product_images/Linear_Ball_Bearings.jpg

Seraph - 05/03/13 - 3:26pm

The one major drawback of this design that I see is the lack of seat post height adjustment. It should at least have a longer seat tube so it can accommodate a dropper post.

Morgan - 05/03/13 - 3:38pm

@ Greene, they are a type of linear bearing. Look at this site for a good cut out view of an example.

http://www.medicaldevice-network.com/contractor_images/schaeffler/2-schaeffler.jpg

Topmounter - 05/03/13 - 6:31pm

The adjustable tire pressure thing is pretty cool. I’m just not sure why I would want a fullsus fatbike.

g - 05/04/13 - 3:03pm

@Seraph- That is the ONE major drawback of this design? I think it would be easier to identify aspects of this design that aren’t drawbacks.

Ryan - 05/06/13 - 9:34am

I think it’s neat, but this is the whole reason I got burned out on biking many years ago and why I now ride a SS rigid. Simplicity is not only beautiful, but fun.

PaulM - 05/07/13 - 7:36am

“Due to the angle of the rear suspension and the front fork, the front and rear tire have the exact same axle path.”

Wasn’t that the concept between the Maverick ML7 using conventional pivots (albeit with an odd shock)?

Bike looks brilliant. So what if its weird, boundaries need to be pushed and doing it on an oddball bike gets you noticed.

GT - 05/09/13 - 9:17pm

Why use a CO2 bottle? Would it be possible to use the compression strokes of the shock absorbers to generate air pressure ?

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