Tiny Yet Functional Bike Built From Scratch

March 31, 2023 by Lewin Day 10 Comments

Sometimes, you just want to go ride your bike in the great outdoors, but you can’t be bothered throwing it in the back of the car. That wouldn’t be a problem if you rode this latest build from [The Q]: a bike small enough to fit in a handbag.

The build starts by customizing a rollerblade wheel to act as the driven rear wheel of the bike. It’s fitted with a tiny sprocket allowing it to be chain driven. Welding some steel tubes then nets a small diamond-layout bike frame. It’s fitted with a chain ring, pedals, and steering assembly just like a full-sized bike, just in absolute miniature.

Riding the bike is “uncomfortable,” in [The Q]’s own terms, but entirely possible. It basically requires the same level of contortion and technique as displayed by the clowns of your local circus. Don’t expect to use it as viable transportation, though. Walking would be much faster.

We’ve seen [The Q] build some wild bikes before, too, like this great hubless design. Video after the break.

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A line art schematic of a bicycle CVT drive. Two large green circles at the bottom have the text "1. Increases speed" where the crank arm would enter the system. A series of cam arms highlighted in red say "2. Converts from rotary to reciprocating motion." Finally, a blue highlighted bearing says "3. Converts from reciprocating back to rotary motion."

A Look Inside Bicycle Gearboxes

March 2, 2023 by Navarre Bartz 23 Comments

While bicycle gearboxes date back to at least the 1920s, they’re relatively unseen in bike racing. One exception is Honda’s race-winning mid-drive gearboxes, and [Alee Denham] gives us a look at what makes these unique drives tick.

Honda has developed three generations of bicycle gearbox as part of their company’s R&D efforts, but none have ever been released as a commercial product. Designed as a way for their engineers to stretch their mental muscles, the gearboxes were only used in bike races and seen at a few trade shows. In 2004, the third gen “derailleur in a box” led to the first gearbox victory in the Downhill World Cup Circuit.

The third gen gearbox differs significantly from the CVT drivetrains in the first and second generation gearboxes, but it is unclear why Honda abandoned the CVT. [Denham] has a nice animation detailing the inner workings of these CVTs based on information from the original patents for these rarely seen gearboxes.

Derailleurs remain the primary drivetrain in racing due to their lighter weight and higher overall efficiency. While still expensive, the decreased maintenance of gearbox drivetrains make a lot of sense for more mundane cycling tasks like commuting or hauling cargo, but only time will tell if the derailleur can be supplanted on the track and trail.

For more on bicycle drivetrains, check out this chainless digital drivetrain or the pros and cons of e-bike conversions.

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A white longtail cargo bike sits on grass with fenced-in planters behind it. The bike has a basket made of black metal tubes on the front and a passenger compartment behind the rider seat for children made of similar black metal tubes. A white canopy is above the passenger compartment and a solar panel sits atop the canopy.

Solar Powered E-bike Replaces Car Trips

February 7, 2023 by Navarre Bartz 20 Comments

E-bikes can replace car trips for some people, and adding a solar panel can make the fun last longer. [Luke] did some heavy modifications to his RadWagon to make it better, stronger, and faster than it was before.

The first step was replacing the stock 750 W controller with a 1500 W model to give the motor twice the power. [Luke] plans to replace the motor if it gets fried pushing too much juice, but is planning on just being careful for now. To stop this super-powered ride, he swapped the stock mechanical discs out for a hydraulic set which should be more reliable, especially when loading down this cargo bike.

On top of these performance enhancements, he also added a 50 W solar panel and maximum power point tracking (MPPT) charge controller to give the bike a potential 50% charge every day. Along with the OEM kid carrier and roof, this bike can haul kids and groceries while laughing at any hills that might come its way.

Checkout this other solar e-bike or this one making a trip around the world for more fun in the sun.

Smart Bike Suspension Tunes Your Ride On The Fly

January 23, 2023 by Dan Maloney 23 Comments

Riding a bike is a pretty simple affair, but like with many things, technology marches on and adds complications. Where once all you had to worry about was pumping the cranks and shifting the gears, now a lot of bikes have front suspensions that need to be adjusted for different riding conditions. Great for efficiency and ride comfort, but a little tough to accomplish while you’re underway.

Luckily, there’s a solution to that, in the form of this active suspension system by [Jallson S]. The active bit is a servo, which is attached to the adjustment valve on the top of the front fork of the bike. The servo moves the valve between fully locked, for smooth surfaces, and wide open, for rough terrain. There’s also a stop in between, which partially softens the suspension for moderate terrain. The 9-gram hobby servo rotates the valve with the help of a 3D printed gear train.

But that’s not all. Rather than just letting the rider control the ride stiffness from a handlebar-mounted switch, [Jallson S] added a little intelligence into the mix. Ride data from the accelerometer on an Arduino Nano 33 BLE Sense was captured on a smartphone via Arduino Science Journal. The data was processed through Edge Impulse Studio to create models for five different ride surfaces and rider styles. This allows the stiffness to be optimized for current ride conditions — check it out in action in the video below.

[Jallson S] is quick to point out that this is a prototype, and that niceties like weatherproofing still have to be addressed. But it seems like a solid start — now let’s see it teamed up with an Arduino shifter.

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A blue Mercedes SLS AMG sports car body with bicycle wheels. The gull wing is open to reveal the spartan interior and the hood is open to reveal an empty engine compartment since this is actually a bike.

SLS AMG Velomobile

January 9, 2023 by Navarre Bartz 14 Comments

Many gearheads dream of owning a supercar, but their exorbitant prices make them unattainable for all but the most affluent. [Andrzej Burek] decided to make his dreams come true by building his own supercar with a human-powered twist. [YouTube]

At first glance, [Burek]’s SLS AMG looks like the real thing. Pop the hood, and you’ll find this “car” is missing it’s V8 which has been replaced by a beefy speaker pumping out engine sounds from any car you choose. Both driver and passenger can provide propulsion for the sociable tandem, and the power is routed through a differential to the rear wheels. [Burek] decided to install the differential to make installing power assist motors simpler in future revisions of this quadracycle.

[Burek] said it’s taken him four years from buying the first component to the bike’s status in the video after the break. Other than the front and rear bumpers, he built the body himself out of fiberglass to learn how to work with the material. He welded the frame himself as well, and, in a testament to good measurements, the two parts fit together when united despite being built in separate locations. You can checkout more pictures on his Instagram.

If you want some more bike hacks, check out this Open Source Bike Computer or this Exercise Bike Game Controller.

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Developing An Open Source Bike Computer

January 6, 2023 by Bryan Cockfield 45 Comments

While bicycles appear to have standardized around a relatively common shape and size, parts for these bikes are another story entirely. It seems as though most reputable bike manufacturers are currently racing against each other to see who can include the most planned obsolescence and force their customers to upgrade even when their old bikes might otherwise be perfectly fine. Luckily, the magic of open source components could solve some of this issue, and this open-source bike computer is something you’ll never have to worry about being forced to upgrade.

The build is based around a Raspberry Pi Zero in order to keep it compact, and it uses a small 2.7 inch LCD screen to display some common information about the current bike ride, including location, speed, and power input from the pedals. It also includes some I2C sensors including pressure and temperature as well as an accelerometer. The system can also be configured to display a map of the current ride as well thanks to the GPS equipment housed inside. It keeps a log in a .fit file format as well so that all rides can be archived.

When compared against a commercial offering it seems to hold up pretty well, and we especially like that it’s not behind a walled garden like other products which could, at any point, decide to charge for map upgrades (or not offer them at all). It’s a little more work to set up, of course, but worth it in the end. It might also be a good idea to pair it with other open source bicycle components as well.

Thanks to [Richard] for the tip!

Snow Plowing By Bicycle

January 1, 2023 by Bryan Cockfield 44 Comments

There are few challenges more difficult or dangerous than trying to get around the majority of North American cities by bicycle. Not only is the bicycle infrastructure woefully inadequate for safe travel (if it exists at all), but it’s often not maintained to any reasonable standard, either. This goes double in colder areas, where bike paths can essentially become abandoned in the winter after a snowfall. [Phil] found himself in this situation recently after a snowfall in western Canada and decided to DIY his own bike-powered snowplow to help keep his bike paths cleared.

The plow is built around an electric-assisted cargo bicycle, which is almost as rare in North America as bicycle infrastructure itself, but is uniquely suited to snowplow duty. It has a long wheelbase and a large front cargo area that can be weighed down if needed to ensure the plow makes good contact with the ground. The plow itself is built out of sections of plastic 55-gallon drums, which have been cut into two scooping sections and attached to the bike with a wooden 2×4 frame. The plow can be raised or lowered with a ratchet strap mechanism, and the plastic scoop skips over bumps in the path with relative ease.

With this relatively simple mechanism attached to his bike, [Phil] can make sure the trails that he frequents around Vancouver are more suitable for bike travel in the winter. Riding a bicycle through the winter, even in the coldest of climates, is not that difficult with the right support and investment in infrastructure, and this build is the best DIY solution we’ve seen to bicycle infrastructure support outside of adopting something like this remote-controlled snowblower to the job.

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