Bicycles

Pressurized bike frame fills flat tires

Pressurized bike frame fills f...
Choka's functioning AGHATA prototype in tire-inflating action
Choka's functioning AGHATA prototype in tire-inflating action
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A rendering of the planned commercial version of the Choka air system
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A rendering of the planned commercial version of the Choka air system
A rendering of the Choka Gravaël Raw bike
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A rendering of the Choka Gravaël Raw bike
Choka's functioning AGHATA prototype in tire-inflating action
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Choka's functioning AGHATA prototype in tire-inflating action
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When it comes to portable bicycle tire-inflating devices, hand pumps require a lot of effort, while CO2 cartridges are single-use only. That's where the aluminum Choka bike frame comes in, as it doubles as a compressed air tank.

Designed in the French Pyrenees region, the Choka features an airtight down tube with a Schrader valve at the bottom. While still at home, the user attaches the hose of their floor pump to that valve, then pumps the down-tube chamber up to 175 PSI (12 bar). A "security valve" on the underside of the tube automatically lets excess air out if it gets overinflated.

On a subsequent ride, should a tire need inflating, the rider runs an included air hose from the frame's air valve to the air valve on the tire. Utilizing a dial on the frame-end of the hose, they can then control the rate at which the air is released.

This means that they can gradually transfer a bit of air to top up a soft tire, or they can deliver a big rush of air to seat and inflate a tubeless mountain bike tire.

A rendering of the planned commercial version of the Choka air system
A rendering of the planned commercial version of the Choka air system

According to the designers, one "frame-full" of air should be sufficient to inflate three 27.5 x 2.80 tires to 22 PSI (1.5 bar) or two 700 x 45C tires to 60 PSI (4.1 bar).

Plans call for the Choka to be available in two models – the AGHATA (AGgressive HArd TAil) enduro/all-mountain frame, and the Gravaël Raw gravel frame. The former is compatible with 29- or 27.5-inch wheels, or a combination of both, while the latter can be set up with 650B or 700C wheels.

Should you be interested, the Choka is currently the subject of a Kickstarter campaign. Assuming it reaches production, a pledge of €990 (about US$1,163) will get you either an AGHATA or a Gravaël Raw frame, including the air system, bottom bracket and headset.

And if you like the idea of adding a home-pumped reusable compressed air chamber to your existing bike, you might want to check out the frame-mounted RideAir.

Source: Kickstarter

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7 comments
Techrex
?? If the tubular bike frame is pressurized with air, would that make the entire bike a lot more physically resistant to major impact damages from traffic accidents or crashing or falling off cliffs? I mean, would that make the whole unit structure's stronger, while it contains compressed air?
joeblake
Why not have the seat post act as a pump/shock absorber? The safety valve might then be adjustable for how soft or hard the shock is, after the frame is filled. Once the air in the frame is exhausted, simply start pedalling again and the frame would be refilled going over bumps.

But with the air in the frame at pressure, might it not be possible that a crash sufficient to bend the frame might result in a small explosion with metal shrapnel being blasted upwards? Hmmm Be hard to ride with your legs crossed.
Choka
@Techrex, Yes it makes our frames stronger, less dents but also a stronger and stiffer frame.
@joeblacke, we like the idea! For a suspension system that woudl also increase grip we should definitly go for full suspension frame. No risk of "explosions" of any kind:
1 there is a security valve just to relief stress on the welds if the bike is in a non pressurized airplane.
2 the pressure / volume ratio is very very small, if the frame would brake an air leak similar to the ones you have when having a flat would happen.
BlueOak
Clever idea, but ouch, delves into Rube Goldberg territory when compact, lightweight frame-mounted pumps are so readily available at reasonable prices.
Signguy
Brilliant!
Trylon
Seems like ridiculous overkill if all you want is some kind of refillable compressed air source. Instead of forcing a customer to buy a whole, new bike frame – which may or may not be to his or her liking – why not just offer a tank that can slip into a water bottle cage or mount on the cage bosses of any bike they already have and like? Sort of like a small SCUBA tank or a durable, metal version of the reservoir on the Delta Airzound bike horn. Heck, you could attract even more customers by offering a blinged-out, lighter-weight carbon fiber tank as a high-end option. People love carbon fiber.
Pablo
I don't wanna be riding one of those when that pressurized frame tank ruptures! 175psi can drive pieces right to the bone...