Bicycle Gearbox Does It By Folding

April 17, 2025 by Fenix Guthrie 47 Comments

If you’ve spent any time on two wheels, you’ve certainly experienced the woes of poor bicycle shifting. You hit the button or twist the knob expecting a smooth transition into the next gear, only to be met with angry metallic clanking that you try to push though but ultimately can’t. Bicycle manufacturers collectively spent millions attempting to remedy this issue with the likes of gearboxes, electronic shifting, and even belt-driven bikes. But Praxis believes to have a better solution in their prototype HiT system.

Rather then moving a chain between gears, their novel solution works by folding gears into or away from a chain. These gears are made up of four separate segments that individually pivot around an axle near the cog’s center. These segments are carefully timed to ensure there is no interference with the chain making shifting look like a complex mechanical ballet.

While the shift initialization is handled electronically, the gear folding synchronization is mechanical. The combination of electronic and mechanical systems brings near-instant shifting under load at rotational rates of 100 RPM. Make sure to scroll through the product page and watch the videos showcasing the mechanism!

The HiT gearbox is a strange hybrid between a derailleur and a gearbox. It doesn’t contain a clutch based gear change system or even a CVT as seen in the famous Honda bike of old. It’s fully sealed with more robust chains and no moving chainline as in a derailleur system. The prototype is configurable between four or sixteen speeds, with the four speed consisting of two folding gear pairs connected with a chain and the sixteen speed featuring a separate pair of folding gears. The output is either concentric to the input, or above the input for certain types of mountain bikes.

Despite the high level of polish, this remains a prototype and we eagerly await what Praxis does next with the system. In the meantime, make sure to check out this chainless e-drive bicycle.

A New Kind Of Bike Valve?

April 15, 2025 by Fenix Guthrie 50 Comments

If you’ve worked on a high-end mountain or road bike for any length of time, you have likely cursed the Presta valve. This humble century-old invention is the bane of many a home and professional mechanic. What if there is a better option? [Seth] decided to find out by putting four valves on a single rim.

The contenders include the aforementioned Presta, as well as Schrader, Dunlop and the young gun, Clik. Schrader and Dunlop both pre-date Presta, with Schrader finding prevalence in cruiser bicycles along with cars and even aircraft. Dunlop is still found on bicycles in parts of Asia and Europe. Then came along Presta some time around 1893, and was designed to hold higher pressures and be lower profile then Schrader and Dunlop. It found prevalence among the weight conscious and narrow rimmed road bike world and, for better or worse, stuck around ever since.

But there’s a new contender from industry legend Schwalbe called Clik. Clik comes with a wealth of nifty modern engineering tricks including its party piece, and namesake, of a clicking mechanical locking system, no lever, no screw attachment. Clik also fits into a Presta valve core and works on most Presta pumps. Yet, it remains to be seen whether Clik is just another doomed standard, or the solution to many a cyclists greatest headache.

This isn’t the first time we’ve seen clever engineering going into a bike valve.

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Keep Tabs On Your Vehicle’s Needs With LubeLogger

March 28, 2025 by Tom Nardi 21 Comments

It doesn’t matter if its a Vespa or a Peterbilt truck — if you ignore the maintenance needs of your vehicle, you do so at your own peril. But it can be difficult enough to keep track of basic oil changes, to say nothing of keeping records on what parts were changed when. Instead of cramming more receipts into your glove box, maybe give LubeLogger a try.

This free and open source software tool is designed to make it easy for individuals to keep track of both the routine maintenance needs of their vehicles, as well as keep track of any previous or upcoming repairs and upgrades. Released under the MIT license, LubeLogger is primarily distributed as a Docker image that makes it easy to self-host the tool should you wish to keep your data safe at home rather than on somebody’s server out in the Wild West of the modern Internet.

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Admit It. You Want This Go-Kart

March 26, 2025 by Jenny List 17 Comments

Many of us could have been lucky enough to have some form of pedal go-kart in our formative years, and among such lucky children there can have been few who did not wish for their ride to have a little power. Zipping around the neighborhood remained a strenuous affair though, particularly for anyone whose hometown was on a hill. What a shame we didn’t have [Matto Godoy] as a dad then, because he has taken a child’s go-kart and turned it into the electrically-propelled ride of dreams.

Out come the pedals and in goes a wooden floor panel, and at the rear the axle is replaced by a set of hoverboard motors and associated batteries and controllers. The wheels are off-the-shelf wheelbarrow parts, and the 36 V lithium-polymer gives it plenty of go. It looks too small for us, but yes! We want one.

If you want one too, you could do worse than considering a Hacky Racer. And if more motor power is your thing, raid the auto recyclers!

Backyard Rope Tow From Spare Parts

March 20, 2025 by Bryan Cockfield 9 Comments

A few years ago, [Jeremy Makes Things] built a rope tow in his back yard so his son could ski after school. Since the lifts at the local hill closed shortly after schools let out, this was the only practical way for his son to get a few laps in during the week. It’s cobbled together from things that [Jeremy] had around the house, and since the original build it’s sat outside for a few years without much use. There’s been a lot more snow where he lives this year though, so it’s time for a rebuild.

The power source for the rope tow is an old gas-powered snowblower motor, with a set of rollers and pulleys for the rope made out of the back end of a razor scooter. Some polyurethane was poured around the old wheel hub so that the rope would have something to grip onto. The motor needed some sprucing up as well, from carburetor adjustment, fuel tank repairs, and some other pieces of maintenance before it could run again. With that out of the way it could be hoisted back up a tree at the top of the hill and connected to the long rope.

This isn’t the first time [Jeremy] has had to perform major maintenance on this machine either. Three years ago it needed plenty of work especially around the polyurethane wheel where [Jeremy] also had to machine a new wheel bearing in addition to all the other work that had to go into repairing it that time. From the looks of things though it’s a big hit with his son who zips right back up the hill after each ski run. Getting to the tops of ski runs with minimal effort has been a challenge of skiers and snowboarders alike for as long as the sport has been around, and we’ve seen all kinds of unique solutions to that problem over the years.

Open Safety In The Auto Business: Renault Shares Its Battery Fire Suppression Tech

March 7, 2025 by Jenny List 31 Comments

As consumers worldwide slowly make the switch from internal combustion vehicles to lower-carbon equivalents, a few concerns have appeared about electric vehicles. Range anxiety is ebbing away as batteries become bigger and chargers become more frequent, but a few well-publicized incidents have raised worries over fire safety.

Lithium-ion batteries can ignite in the wrong circumstances, and when they do so they are extremely difficult to extinguish. Renault has a solution, and in a rare moment for the car industry, they are sharing it freely for all manufacturers to use.

The innovation in question is their Fireman Access Port, a standardized means for a fire crew to connect up their hoses directly to the battery pack and attack the fire at its source. An opening is covered by an adhesive disk designed to protect the cells, but breaks under a jet of high-pressure water. Thermal runaway can then be halted much more easily.

The licensing terms not only allow use of the access port itself, but also require any enhancements be shared with the rest of the community of automakers using the system. This was the part which caught our interest, because even if it doesn’t come from the same place as the licences we’re used to, it sounds a lot like open source to us.

Oddly, this is not the first time Renault have open-sourced their technology, in the past they’ve shared an entire car.

LTA’s Pathfinder 1: The Dawn Of A New Age Of Airships?

March 4, 2025 by Maya Posch 37 Comments

Long before the first airplanes took to the skies, humans had already overcome gravity with the help of airships. Starting with crude hot air balloons, the 18th century saw the development of more practical dirigible airships, including hydrogen gas balloons. On 7 January 1785, French inventor, and pioneer of gas balloon flight Jean-Pierre Blanchard would cross the English Channel in such a hydrogen gas balloon, which took a mere 2.5 hours. Despite the primitive propulsion and steering options available at the time, this provided continued inspiration for new inventors.

With steam engines being too heavy and cumbersome, it wasn’t until the era of internal combustion engines a century later that airships began to develop into practical designs. Until World War 2 it seemed that airships had a bright future ahead of them, but amidst a number of accidents and the rise of practical airplanes, airships found themselves mostly reduced to the not very flashy role of advertising blimps.

Yet despite popular media having declared rigid airships such as the German Zeppelins to be dead and a figment of a historic fevered imagination, new rigid airships are being constructed today, with improvements that would set the hearts of 1930s German and American airship builders aflutter. So what is going on here? Are we about to see these floating giants darken the skies once more?

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