Sada hubless bike folds down to the size of an umbrella
The Sada Bike folds down small, but has full-size wheels
While we've already seen folding bicycles that pack down into a pretty tiny package, such small-folding bikes usually have at least one limiting factor – puny wheels that limit speed and road-worthiness, not to mention aesthetics. The Sada Bike, however, features full-size 26-inch hubless wheels, yet is about the size of an umbrella when folded.
Italian designer Gianluca Sada has been working on the bike since 2008. He completed construction of an aluminum alloy working prototype three years ago, and is now looking for investors to help bring it to production.
The folding action is initiated simply by pushing forward on the saddle. The wheels detach and aren't part of the umbrella-sized package, although Sada has plans for them.
He envisions the folded bike being carried in an included backpack, and the two wheels would serve as the supporting structure of that pack. Because they have no hubs or spokes, there would be room inside the backpack to carry other items, besides the folded bike frame.
Alternatively, the pack could be pulled like a wheeled suitcase – converting it to that configuration would involve releasing a central hinge to widen its stance, and extending an included handle. The bottoms of the bike's wheels would protrude through openings in the bottom of the backpack, allowing them to also serve as its wheels.
The prototype bike can be seen in action in the video below.
Source: Sada Bike via Gizmodo
About the Author
An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.
All articles by Ben Coxworth
How much does it weigh? Does it become a 30lb umbrella?
I think this is really neat since it has hubless wheels and it folds down to be really portable. Having regular wheels means it can ride like most bikes.
"The wheels detach and aren't part of the umbrella-sized package ...'
So he solves the folding-bikes-have-puny-wheels problem by simply not including them in the package. Well done that man, well done.
Very cool. Seriously this is one of the best designs I have seen. How much is the question. I really like some of these concept bikes but the 100K price tag for some of them is not inspiring. More like a crewel joke.
Strangely the video doesn't demonstrate the bike being folded.
Would be interested to see how those wheels would tolerate being bumped up or down kerbs, steps etc. Ingenious folding mechanism, though.
I admire the looks and style (Italians...how do they do it!), and the clever wheels. But I don't understand why small wheels need to be avoided. If you pay enough attention to style when designing a small-wheel bike, I am sure it too will look great.
T N Args
Hard to tell from the pictures but it looks like the rear rim is driven only via friction (ie there is no teeth cut into the inside of the rear rim). How will this perform if the rear rim gets wet (raining, ride through a puddle etc)?
The drive chain also goes very close to the ground, so again if you ride after it has rained the chain is going to get filthy.
Also is this effectively a fixie? Can't see any brakes. If these is only friction between the drive roller and the rim and it is the only way to slow down, then I would be very hesitant to ride it in the wet.
Hubless wheels go back at least thirty years. I remember seeing a Swiss prototype in 1984 in a cycling magazine. It had friction based gear chain drive to the rear wheel, with both rims rolling on three rollers.
Think I shall stick to my Birdy ,,,,
The rims essentially become part of a very large bearing, many problems with friction, even when clean, but open to ingress of ..almost anything from litter, to squirrels, and beyond. Nice looking, tho'.
wet braking/drive train
chain on the ground,, dirt
As a designer, I am amazed by this design. Beautiful.
As usual far too many negative comments. Amazing how negative your average fellow is.
Beautiful execution. I'd feel better if there was some torsional stability on that front wheel i.e., without a lower roller it may gave the desire to collapse sideways. Maybe I'm just extra careful but when a design causes me to experience the sensation of falling, I double-check the assumptions.
To make the rim strong enough to withstand the loads it must carry, it would have to be made of very thick walled tube. I don't know what it would weigh, but it would be much heavier than a regular rim and probably heavier than a regular spoked wheel and hub of the same size. That weight doesn't even factor in the additional weight of the bogey wheels and their framework. The overall weight would be significantly higher than a standard wheel and fork.
The rear wheel has no loading except at the bottom contact point. The front wheel has a compressive load due to top loading. If the "fork" were extended to the bottom of the front wheel, it might create other design opportunities for low stressed wheels (at least until a curb is encountered).
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