Choka Is the World’s First Pressurized Bike Frame, So You Can Always Fix a Flat
October 13, 2020
Even riding on tarmac is not without risk of flat tires, but this risk is considerably higher when it comes to hitting the trail. An underinflated, soft tire is also cause for underwhelming performance, and can be fixed with the usual means: either a hand pump or a CO2 cartridges. Either comes with disadvantages that take away from the pleasure of the ride.
“We want to create simple, playful and durable bicycles with a little extra in case of a flat tire,” the designers say. “We dream of a better world, without disposable CO2 cartridges but with a lighter and more efficient solution than hand pumps.”
The idea for the Choka frame is to offer a product that holds the air you need in case of an underinflated or even a flat tire. The downtube serves as a compressed air tank, which you top up with air at home, in your own time and at your own convenience, without losing precious time you could have spent riding. Then, when you head out, should you need more air into either or even both tires, you hook up the frame to the tire and you’re done.
Through a Schrader valve, you pump air into the bike frame, up to 175 PSI (12 bar), and there’s a Flow Variator that helps you inflate your tire precisely and without any loss of pressure. Because the frame is made of aluminum alloy and it’s not permeable, you will be able to use it some other time, should you not need the air on the very next ride. With this air reserve, you can inflate 2 to 3 tires, depending on your needs at any given moment. “With one frame full, you can pump three 27.5 x 2.80 tires to 22 PSI or two 700 x 45 tires to 60 PSI,” the designers say.
To let out excess air if you happen to pump too much of it into the frame, there’s a “security valve” on the underside of the tube. The whole system is lightweight and, as per the designers, “ecological” in that you won’t be making waste with single-use CO2 cartridges. You won’t have to worry about forgetting your hand pump at home, either.
In case you’re wondering what it means to ride on a pressurized bike frame, especially on technical trails, the designers say you shouldn’t worry. The air inside actually makes the frame more resistant to falls and bumps, and if a fissure does occur, it shouldn’t feel any different from the hiss you get when you get a flat tire. That is to say, the frame won’t burst when you hit the ground with it.
Choka offers two different models of frame right now with this pressurized downtube: the Agatha, which is for enduro / all-mountain rides, and whose name stands for AGgressive HArd TAil, and the Gravaël, which is for the road and gravel. Both offer certain customization options and work with a variety tire sizes, and are said to have been duly put through their paces for durability.
You can get either frame for a pledge of €990 ($1,167 at today’s exchange rate), with an estimated delivery date set for December 2020, assuming nothing comes up to delay production of these first units. As of the moment of press, it doesn’t look like the crowdfunding community is particularly impressed with the proposition, based on the amount of pledges. Then again, there are still 18 days to go in the campaign, and things could still turn around.
Here are the designers explaining how Choka works, with typical French flair for overacting.