It is pretty easy to go to a big box store and get a digital speedometer for your bike. Not only is that no fun, but the little digital display isn’t going to win you any hacker cred. [AlexGyver] has the answer. Using an Arduino and a servo he built a classic needle speedometer for his bike. It also has a digital display and uses a hall effect sensor to pick up the wheel speed. You can see a video of the project below.
[Alex] talks about the geometry involved, in case your high school math is well into your rear view mirror. The circumference of the wheel is the distance you’ll travel in one revolution. If you know the distance and you know the time, you know the speed and the rest is just conversions to get a numerical speed into an angle on the servo motor. The code is out on GitHub.
Continue reading “Arduino + Geometry + Bicycle = Speedometer”
Mini Sumo seems like one of those hobbies that starts out innocently enough, and ends up with a special room in the house dedicated to it. One day you’re excitedly opening up your first Basic Stamp kit, and the next you’re milling out mini molds on a mini lathe to make mini extra sticky tires.
[Dave] started out trying to find a part from the local big box store that was just a little bigger than the wheel he wanted to rubberize. He set the wheel inside a plumbing cap and poured the urethane in. It worked, but it required a lot of time with a sharp knife to carve away the excess rubber.
In the meantime he acquired a Sherline Mini Mill and Lathe. With the new tools available to him, he made a new mold out of a bit of purple UHMW and some acrylic. This one produced much nicer results. Using a syringe he squeezed resin into the mold through a hole in the acrylic. Much less cleanup was needed.
He later applied these methods to smaller, wider wheels as his mini sumo addiction took a stronger hold on his life.
Somewhere between the early tires forged by wheelwrights and the modern steel-belted radial, everyone’s horseless carriage rode atop bias-ply tires. This week’s film is a dizzying tour of the Brunswick Tire Company’s factory circa 1934, where tires were built and tested by hand under what appear to be fairly dangerous conditions.
It opens on a scene that looks like something out of Brazil: the cords that form the ply stock are drawn from thousands of individual spools poking out from poles at jaunty angles. Some 1800 of these cords will converge and be coated with a rubber compound with high anti-friction properties. The resulting sheet is bias-cut into plies, each of which is placed on a drum to be whisked away to the tire room.
Continue reading “Retrotechtacular: Brunswick Shows A Bias for Tires”
Your car’s tire is losing air from the valve stem — what do you do? Well you could take it to the mechanic and pay upwards of $30 to replace it… or you could try this MacGyver style approach!
Not wanting to take his car to the shop, [David] tried several ways of knocking the tire off its bead. Hitting it with a sledge hammer… Jumping on it… throwing it against the ground… In the end, he realized leverage would be his friend! He’s constructed a tool out of a few pieces of wood — simply place it on the tire near the valve stem, and then drive up the wood with your car. The weight of the car easily compresses the tire leaving you just enough room to pull the tire valve stem out, and put a new one in.
It’s pretty much the same method shops use, they just have a machine to do it for them — because of this, so we don’t think this would hurt your tire. As always though, we’d love to hear what you guys think in the comments! Stick around for the video to see [David’s] process.
Continue reading “Replacing a Tire Valve Stem Without Special Tools!”
These shoes are heavier than normal, they don’t grip as well as store-bought, and it’s a heck of a lot of work to make a pair for yourself. But if you do pull this one off you’ll have a great time showing everyone your custom tire tread shoe hack.
Two things motivated [Martin Melchior] to give this a try. The first is that tire tread is virtually indestructible when only supporting the weight of a person. Secondly, this reuses otherwise worn-out tires, making it a recycling project.
Pretty much all of the work has to do with getting the tread ready for use. Cutting off the sidewalls and sawing the ring of tread in half is rather easy. But then you have to split the tread off of the steel belts, which is not. [Martin] recommends using vice-grip pliers to grab the outer lay and pull it away from the tread, slicing along the belts with a utility knife as you go. Once you do have a flat strip just glue it to your shoes and cut away the excess.
We’re more into a different type of retread that actually takes you places.
A new breed of tire has been developed that won’t go flat, even if it gets bombed. Resilient Technologies L.L.C. has started making these decidedly cool looking tires for the military. The honeycomb of stiff but flexible plastic acts as a shock absorber just as an air filled tire would. Unlike a normal tire, it won’t pop. You would have to completely destroy the tire to stop these. The article mentions that this isn’t the first of its kind. Michelin has made the “tweel” for industrial uses, but you may recall the video of the Audi driving around a course using them. If not, check it out after the break.
Continue reading “Honeycomb tire won’t go flat”