3D Printed Tires, By The Numbers

What does it take to make decent tires for your projects? According to this 3D printed tire torture test, it’s actually pretty easy — it’s more a question of how well they work when you’re done.

For the test, [Excessive Overkill] made four different sets of shoes for his RC test vehicle. First up was a plain PLA wheel with a knobby tread, followed by an exact copy printed in ABS which he intended to coat with Flex Seal — yes, that Flex Seal. The idea here was to see how well the spray-on rubber compound would improve the performance of the wheel; ABS was used in the hopes that the Flex Seal solvents would partially dissolve the plastic and form a better bond. The next test subjects were a PLA wheel with a separately printed TPU tire, and a urethane tire molded directly to a PLA rim. That last one required a pretty complicated five-piece mold and some specialized urethane resin, but the results looked fantastic.

Non-destructive tests on the tires included an assessment of static friction by measuring the torque needed to start the tire rolling against a rough surface, plus a dynamic friction test using the same setup but measuring torque against increasing motor speed. [Overkill] threw in a destructive test, too, with the test specimens grinding against a concrete block at a constant speed to see how long the tire lasted. Finally, there was a road test, with a full set of each tire mounted to an RC car and subjected to timed laps along a course with mixed surfaces.

Results were mixed, and we won’t spoil the surprise, but suffice it to say that molding your own tires might not be worth the effort, and that Flex Seal is as disappointing as any other infomercial product. We’ve seen other printed tires before, but hats off to [Excessive Overkill] for diving into the data.

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Retrotechtacular: Ford Model T Wheels, Start To Finish

There’s no doubt that you’ll instantly recognize clips from the video below, as they’ve been used over and over for more than 100 years to illustrate the development of the assembly line. But those brief clips never told the whole story about just how much effort Ford was forced to put into manufacturing just one component of their iconic Model T: the wheels.

An in-house production of Ford Motors, this film isn’t dated, at least not obviously. And with the production of Model T cars using wooden spoked artillery-style wheels stretching from 1908 to 1925, it’s not easy to guess when the film was made. But judging by the clothing styles of the many hundreds of men and boys working in the River Rouge wheel shop, we’d venture a guess at 1920 or so.

Production of the wooden wheels began with turning club-shaped spokes from wooden blanks — ash, at a guess — and drying them in a kiln for more than three weeks. While they’re cooking, a different line steam-bends hickory into two semicircular felloes that will form the wheel’s rim. The number of different steps needed to shape the fourteen pieces of wood needed for each wheel is astonishing. Aside from the initial shaping, the spokes need to be mitered on the hub end to fit snugly together and have a tenon machined on the rim end. The felloes undergo multiple steps of drilling, trimming, and chamfering before they’re ready to receive the spokes.

The first steel component is a tire, which rolls down out of a furnace that heats and expands it before the wooden wheel is pressed into it. More holes are drilled and more steel is added; plates to reinforce the hub, nuts and bolts to hold everything together, and brake drums for the rear wheels. The hubs also had bearing races built right into them, which were filled with steel balls right on the line. How these unsealed bearings were protected during later sanding and grinding operations, not to mention the final painting step, which required a bath in asphalt paint and spinning the wheel to fling off the excess, is a mystery.

Welded steel spoked wheels replaced their wooden counterparts in the last two model years for the T, even though other car manufacturers had already started using more easily mass-produced stamped steel disc wheels in the mid-1920s. Given the massive infrastructure that the world’s largest car manufacturer at the time devoted to spoked wheel production, it’s easy to see why. But Ford eventually saw the light and moved away from spoked wheels for most cars. We can’t help but wonder what became of the army of workers, but it probably wasn’t good. So turn the wheels of progress.

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Hackaday Links: May 19, 2024

If there was one question we heard most often this week, it was “Did you see it?” With “it” referring to the stunning display of aurora borealis — and australis, we assume — on and off for several days. The major outburst here in North America was actually late last week, with aurora extending as far south as Puerto Rico on the night of the tenth. We here in North Idaho were well-situated for prime viewing, but alas, light pollution made things a bit tame without a short drive from the city lights. Totally worth it:

Hat tip to Tom Maloney for the pics. That last one is very reminiscent of what we saw back in 1989 with the geomagnetic storm that knocked Québec’s grid offline, except then the colors were shifted much more toward the red end of the spectrum back then.

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Hackaday Links: November 12, 2023

Somebody must really have it in for Cruise, because the bad press just keeps piling up for the robo-taxi company. We’ve highlighted many of the company’s woes in this space, from unscheduled rendezvous with various vehicles to random acts of vandalism and stupid AI pranks. The hits kept coming as California regulators pulled the plug on testing, which finally convinced parent company General Motors to put a halt to the whole Cruise testing program nationwide. You’d think that would be enough, but no — now we learn that Cruise cars had a problem recognizing children, to the point that there was concern that one of their autonomous cars could clobber a kid under the right conditions. The fact that they apparently knew this and kept sending cars out for IRL testing is a pretty bad look, to say the least. Sadly but predictably, Cruise has announced layoffs, starting with the employees who supported the now-mothballed robo-taxi fleet, including those who had the unenviable job of cleaning the cars after, err, being enjoyed by customers. It seems a bit wrongheaded to sack people who had no hand in engineering the cars, but then again, there seems to be a lot of wrongheadedness to go around.

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Homebrew Tire Inflator Pushes The Limits Of PVC Construction

Let’s just clear something up right from the start with this one: there’s literally no reason to build your own tire inflator from scratch, especially when you can buy a perfectly serviceable one for not a lot of money. But that’s missing the point of this build entirely, and thinking that way risks passing up yet another fascinating build from PVC virtuoso [Vang Hà], which would be a shame

The chances are most of you will recall [Vang Hà]’s super-detailed working PVC model excavator, and while we’re tempted to say this simple air pump is a step toward more practical PVC builds, the fact remains that the excavator was a working model with a completely homebrew hydraulic system. As usual, PVC is the favored material, with sheet stock harvested from sections of flattened pipe. Only the simplest of tools are used, with a hand drill standing in for a lathe to make such precision components as the compressor piston. There are some great ideas here, like using Schrader tire valves as the intake and exhaust valves on the pump cylinder. And that’s not to mention the assembly tips, like making a hermetic seal between the metal valves and the PVC manifold by reaming out a hole with a heated drill bit.

We’re not sure how much abuse a plastic compressor like this will stand up to, but then again, we’ve seen some commercially available tire inflators with far, far less robust internals than this one.

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Where Pollution Hits The Road: The Growing Environmental Hazard Of Rubber Tires

As ubiquitous as rubber tires are due to the many practical benefits they offer to cars, trucks, and other conveyances, they do come with a limited lifespan. Over time, the part of the tire that contacts the road surface wears away, until a tire replacement is necessitated. Perhaps unsurprisingly, the material that wears away does not magically vanish, but ends up in the environment.

Because of the materials used to create tires, this worn away material is counted as a microplastic, which is a known environmental pollutant. In addition, more recently it’s been found that one additive commonly found in tires, called 6PPD, is highly toxic to certain species of fish and other marine life.

There are also indications that these fine bits of worn-off tire contribute to PM2.5 particulate matter. This size of particulates is fine enough to penetrate deep into the lungs of humans and other animals, where they can cause health issues and exacerbate COPD and similar conditions. These discoveries raise a lot of questions about our use of tires, along with the question of whether electric vehicles stand to make this issue even worse.

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DIY Airless Tires Work Surprisingly Well

Airless tires have been “a few years away” from production for decades now. They’re one of the automotive version of vaporware (at least those meant for passenger vehicles), always on the cusp of being produced but somehow never materializing. They have a number of perks over traditional air-filled tires in that they are immune to flats and punctures, and since there aren’t any airless tires available at the local tire shop, [Driven Media] decided to make and test their own.

The tires are surprisingly inexpensive to make. A few pieces of drainage tubing of varying diameters, cut to short lengths, and then bolted together with off-the-shelf hardware is all it takes, although they note that there was a tremendous amount of hardware needed to fasten all the pipe lengths together. With the structure in place they simply cut a tread off of a traditional tire and wrapped it around each of the four assemblies, then bolted them up to their Caterham street-legal race car for testing.

While the ride quality was notoriously (and unsurprisingly) rough and bumpy, the tires perform admirably under the circumstances and survive being driven fairly aggressively on a closed-circuit race course. For such a low price and simple parts list it’s shocking that a major tire manufacturer like Michelin hasn’t figured out how to successfully bring one to a light passenger car yet.

Thanks to [Itay] for the tip!

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