3D Printing A Usable Airless Tire

For decades now, companies like Michelin have been teasing us with futuristic-looking automobile tires that don’t use air. Instead, they use a polymer mesh of sorts which maintains the same pressure on the travel surface that a pneumatic tire does, with much less maintenance than their pneumatic counterparts. At least, in theory. There’s a reason that these tires live in the same mythical realm that Half Life 3 and the modern affordable Volkswagen do, and [Berm Peak] decided to discover those reasons for himself.

Of course, [Berm Peak] isn’t building these for his daily driver, an electric pickup truck featured in previous videos of his. He’s putting these on his mountain bike instead, a challenging environment for a tire like this in its own right. When mountain biking at the level he does, punctures and flats can become a real nuisance on the trail, so he set about experimenting with these designs with the 3D printer to see if he could make something rivaling pneumatic technology. After a few design iterations he settled on a TPU-based version with a compliant S-shaped spacing between the tread and wheel. The tire printed in sections that are installed by joining them together on the bike rim with a separate 3D printed rim interface.

At the end of this process [Berm Peak] ends up with a surprisingly capable tire that mostly holds up to his extreme off-road testing, an impressive feat for something 3D printed in his shop. Presumably a company specializing in bicycle tires could build something even more capable, but it turns out that a different technology has already solved all of the problems that airless tires solve. Mountain bikers today almost exclusively ride on tires with sealant, so punctures and flats are essentially a solved problem. But the neon-green airless tires were still a fun project for [Berm Peak] and quite the head-turner out on the bike trails.

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Bike Trainers As Video Game Controllers

While we’ve largely settled on analog sticks and digital buttons for controlling video games, there’s all sorts of projects to create truly esoteric controllers that allow playing games in unique ways. This one from [sukolupo] lets you use data from standard bike trainers to get your virtual character moving.

Called Deck de France, it maps the data coming from one of the supported bike trainers to a virtual controller which can then be “plugged in” to a Linux system, in this case a Steam Deck mounted to the trainer’s handlebars. Although a bike trainer doesn’t have the same number of inputs as a modern gaming controller, it does have enough to play games like Rocket League. As you might expect, it’s also perfect for biking titles such as the Tour de France series.

As far as unique controllers for video games go, this one is surely up in the rankings with a real trombone or a controller purpose-built for riding virtual horses. It’s also a great way for those who are getting a bit bored of riding their trainers to breathe some new life into their exercise routine. We’ve also seen some open-source alternatives for modern bike trainer software as well, which is another great way to get excited about exercise equipment too.

Use Your Head While Trimming Trees

[Attoparsec] occasionally rides a bicycle for transportation, but with the major downside of doing this in North America, a place where bicycle infrastructure is generally neglected. From snow removal, maintenance, separation from cars, or even existing in the first place, the places bicyclists use are generally last to be cared for. One of these deficiencies is landscaping maintenance, with plant growth routinely extending into travel ways. Rather than continue to get hit in the face by tree branches, [Attoparsec] took matters into his own hands, or in this case, head.

Since he’s riding down the bike path anyway, the original thought was to add a trimmer to the front of the bicycle. This has a notable downside of being dangerous to others, so instead he added a string trimmer to his helmet. The electric trimmer was scavenged from an old handheld landscaping tool, with a 3D printed mount designed in CAD to cleanly mount to his bicycle helmet. It’s wired to a control on the handlebar, so when a branch is coming up it can be activated by hand and then pruned without much thought other than properly aiming one’s head.

By most measures this eccentric contraption seems to work quite well. There’s not enough torque to affect the rider’s head in any negative way, the strings are long enough to reach far enough to trim the leaves and branches before they can impact the rider’s face, and it’s safe for other users of the bike path. [Attoparsec] calls this “guerrilla urban landscaping”, a bit different from other forms of guerrilla gardening we have seen before.

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Open-Source Mid-Drive E-Bike Motor Has Lots Of Promise, And Hyphens

[Pedro Neves] has a mid-drive e-bike, but he doesn’t own it — not truly, since he can’t repair the motor unit. For a hacker to be in that position, there are only two options: crack the old one and make it your own, or build your own from scratch. [Pedro] built his own and is open-sourcing it on his website for everyone to play with. Right now, that’s .step files and a BOM, so you’ll need to watch the design/build video on YouTube below to get the full picture.

His choice of a motor from an old battery-powered angle grinder is both thrifty and environmentally friendly, so we approve. His goal of 25 km/h seems like a reasonable speed limit, but may still be too fast for some countries’ regulations— so do check the local rules if you’re going to build this. Making the most of 3D-printed components is also a choice that makes the project more accessible, but don’t worry — the bearing surfaces are all metal. That includes the clutch bearing that will let you pedal home if the battery dies or the motor craps out. Well, unless the printed plastic axle gives up the ghost, but that got replaced with a CNC version, so it’s all good. Unless you’ve got legs like Hercules, it ought to hold.

If that’s not DIY enough, you could always build the motor yourself. This mid-drive is also part of a larger project [Pedro] is working on for a whole cargo bike, as he details in his video, which is a worthy project we’ve seen other examples of before.

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Tricking A Bike Counter

Some municipalities implement bike counters on cycling routes in order to monitor traffic. [nullpxl] recently investigated how these counters work, and explored methods that can be used to trick the counter into thinking a bike passed over it.

A great many of these devices are built using inductive loop sensors. This involves passing a current through a loop of wire embedded in the ground. When a conductive item such as the metal wheel of a bike passes through the electric field, eddy currents are generated in the item, creating their own magnetic field which reacts with the loop’s field itself. This creates a change in inductance which can be measured, and thus used to log the number of times a conductive item has passed over the sensor. By looking at the signature of the inductance change, a system can be tuned to detect specific objects—for example, two bicycle wheels passing over a sensor will create a signal that varies over time in a characteristic way.

[nullpxl] first tried to recreate a “bike” signal for the inductive loop by running over the area holding two metal pans. This wasn’t close enough, so a new idea was needed. Experiments with a scrap bike then indicated that there was a speed gate involved, and that wheeling one wheel over the sensor and back again could trick the sensor into thinking a bike had passed by. Eventually, [nullpxl] distilled all this learning down to create “the BIKE BASKET.” It’s simply a bag with a bike wheel in it, and swinging it over the sensor twice makes the counter tick up.

Is there any money in tricking the average municipal bike counter in your local city? We doubt it, unless Big Bike is getting increasingly filthy in its lobbying efforts. In any case, we love to see weird sensor hacks around these parts. Continue reading “Tricking A Bike Counter”

A Bicycle Built On An Italian Renaissance Tech Base

There is a drawing of a bicycle in one of Leonarda DaVinci‘s sketchbooks– except it wasn’t drawn by DaVinci, and dates long after his death, so we can’t say the old master invented the bicycle. We can, however, wonder what it would have looked like if he did– and so did the [How To Make Everything] YouTube channel. As you might expect, they investigated the question of a Renaissance Bicycle in the best possible way: they built one.

In some ways the device looks like the first, primitive hobby-horse proto-bicycle of the early 19th century, which is not without reason. From the renaissance to the dawn of the industrial era, there wasn’t a huge change in how europeans worked with wood, and in both eras wood is the obvious choice. Where this bike differs from [Karl Drais]’s invention is that it has both pedals and brakes– both of them using drawings from DaVinci’s sketchbook.

You might be surprised to learn that ball-bearings are period-appropriate, and weren’t even invented by DaVinci. The drum brake, on the other hand, is right out of the Old Master’s notes: a steel band wraps around a drum on the rear break, and is tighened by a lever. With iron rims, no brake would stop on a dime, and this probably works as well as anything while being quite simple to make.

The chain is also based on one in DaVinci’s notes, and honesty it’s a weak point of the design; they’d likely have been better off with a leather belt, or perhaps a stack of gears as we’ve seen before. The hand-made chain just isn’t able to get the bike up to riding speed. Still, this is recognizably a bicycle and entertaining content for anyone who plans on violating the temporal prime directive or wants to get around after the apocalypse.

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Challenging The Way We Pedal

The bicycle is an invention that has not changed in its fundamentals since the first recognisably modern machines appeared in the closing years of the 19th century. Its frame uses a structure of two triangles, its wheels are equal in size, and it’s propelled by a pedal crank and (in most cases) a chain. Bicycles have improved vastly in materials and performance, but if you were to wheel a 2026 tourer into an 1886 bike shop, the Victorian proprietor would recognise it. Only a very brave engineer would try to fundamentally change such a formula, but here’s [Not programming] with a crankless bicycle.

The idea is to replace the crank’s circular motion with a linear one, thus providing a more constant propulsion. The build was inspired by another that used a sinusoidal track in a rotating cylinder to achieve the necessary conversion. This design takes a different tack, using an arrangement of gears and freewheels he describes as a mechanical rectifier to convert the back-and-forth motion of pedaling into rotation. The pedals themselves are stirrups mounted at each end of a V-belt.

This build is an exercise in pushing the limits of 3D print strength, as prototype after prototype shears under load. He does finally get the thing to work, though, and we admire his persistence. Oddly, this isn’t the first 3D-printed bicycle geartrain we’ve seen.

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