This reminds me of the time I happened to be at a warehouse where an industrial motor control panel was being decommissioned. In the center of the panel is a large breaker, which was dutifully opened (ie powered off) before work commenced. But bizarrely, someone in the past managed to tap power from the supply-side of the breaker for some sort of monitoring sensor inside the panel. So when that circuit was cut through, there was a loud bang and the overhead lights went out.

No one was injured, although everyone was jumpy from the inadvertent light-and-sound spectacle. And a set of cutters gained a 12 AWG-sized (approx 4 mm^2) hole.

I may have misremembered some details, but my takeaway as a non-electrician was to 1) never assume a breaker handle at face value, and 2) don’t assume the prior person made sane choices.

This is a good question and I don’t really know how this device would affect drafting and related manoeuvres. But if I had to guess, drafting behind a lead cyclist should still be beneficial, but the “zones” where it works might change.

So for example, the optimal distance lee-ward of a lead cyclist might become shorter or longer. Longer could mean more space to vie for that position directly behind the lead. But shorter might mean it’s impossible to draft without crashing into the lead.

Side-to-side drafting distances might also be affected, like how birds travel in a vee-shape. Maybe the vee would become wider? That might not be beneficial, though, if it’s so wide that it’s impossible to stay on the racecourse.

TL;DR: I have no idea, and aerodynamics are hard. That’s why I’m intrigued by the field.

My understanding is that it has to do with form drag – aka pressure drag – which results in vortices forming in the “separation region” directly behind an airfoil. Or in this case, a rider. Essentially, the swirling of air behind the rider is turbulent – which is why a hoodie might flop all over the place – and that causes energy to be lost.

This video on Nebula (and YT as well) describes pressure drag at about the 02m30s mark for a sphere. But this graphic from Skybrary also shows the problem:

By providing a smooth surface for air to “cling” to, where it would otherwise form vortices in the separation region, should reduce form drag, although it will cause additional induced drag (aka friction with the new surface). But induced drag scales with speed and at cycling speeds, that’s less a problem than it would be at airplane speeds.

A related drag-reducing device has been used for semi-truck trailers, and those have really been proven to reduce fuel consumption. Although the Wikipedia article does not describe in detail the aerodynamic principles at play.

For reference, the current Flag of Milwaukee, WI, which is quite busy:

As for the so-called “People’s Flag” – either with or without the city hall barreling into the harbor – it bears a small resemblance to the flag of Reno, NV, which is a pleasing flag.

Robert Lenz’s “Sunrise Over the Lake”, selected after a public competition, which prompted the humorous version with the city hall building.

To be clear, the legs would support the topper when it’s positioned over the tub, and also support the topper when it’s beside the tub? If that’s the case, do the legs really need to fold away? Would fixed legs be acceptable? Or is there a requirement that the legs be foldable to provide clearance over the edge of the tub?

Sigh. The editor strikes again, with a headline that is clickbait-y for an otherwise informational article. A more accurate headline would be: “what are hookless wheels, what benefits do they have, and how are they tested for parity to hooked wheels”.

The safety aspect – which the author and Envee lead with – can be distilled to this single, nebulous, unsupported statement:

Greater dimensional stability means a safer wheel.

In both computer and physical security, one of the perennial issues is that humans are bad at understanding risk. So if you say a door is 20% less likely to be kicked in, or this firewall protects against more intruders, what does that really mean? Most people do poorly at quantitative comparisons, but are usually fine at qualitative comparisons. So risk becomes viewed as “more risky” or “less risky”, compared to some standard, but the magnitude is dropped.

Risk is the other side of safety, so the idea of “more safety” is always going to be appealing. But the magnitude of a safety improvement is all-important for making proper evaluations.

To drive the point using a different bicycle component, let’s look at ball bearings, used for every rotating surface on a bike. As a definition for dimensional stability, I am using the one from this page:

A property of materials that allows them to maintain their original shape and dimensions throughout the manufacturing process, storage, and use.

Certainly, a ball bearing – almost by name – must be as round as possible, meaning it has just one dimension of paramount importance, its diameter (I am grossly oversimplifying). Deviations of a ball bearing will be compared against a theoretical sphere of a nominal diameter, so the stability is how far away the bearing might deform from that nominal value. This includes everything from manufacturing tolerance to operating environment (eg temperature and humidity).

Some factors will be totally controlled at the factory, such as the initial dimensions when it comes off the line. Careful machining can bring the tolerances even closer to perfect. For in-use tolerance control, the choice of material has a large impact, as some metals and alloys expand or contract at slower rates.

But while we could focus on delivering a bicycle ball bearing that is guaranteed to be within +/- 0.0025 mm, what does that really translate to? Does a bicycle ride substantially better with 0.0025 mm tolerance bearings than, say, 0.01 mm tolerance? How much is enough?

It’s very likely that hookless wheels have greater dimensional stability, and but “more” doesn’t mean always mean “better” and “safer”. As technology becomes capable of delivering even more impressive technical measurements, we need to keep in mind that the benefits become more limited and niche.

I appreciate that the three other hookless wheel manufacturers did not lead with safety, but focused on the performance aspect of their designs. That’s something which racing cyclists would find useful, as things like aerodynamics matter a lot.

The article does a good job at distilling the intricacies of the hookless wheel and is a worthy read. And while I do not expect this to become the predominant wheel design for the entire world’s bicycles, it’s nice to see design innovation. Just don’t needlessly couch it as a safety innovation.

This is correct, although it may be for good reason: data for non-rider ebike injuries and deaths is not collected through the existing means, which focus mostly on motor vehicle collisions. The NHTSA’s 2022 data report has this note:

Prior to 2022, motorized bicycles were collected as motor vehicles and classified as motorcycles in FARS and CRSS, and their operators and passengers were captured as motorists. Beginning in 2022, FARS and CRSS are no longer collecting motorized bicycles as motor vehicles. Consequently, operators and passengers of motorized bicycles will be captured as pedalcyclists when involved in a motor vehicle traffic crash. Any traffic crash involving only motorized bicycle(s) will no longer be captured in FARS or CRSS.

Essentially, the national data sources available today don’t record bicycle-vs-bicycle or bicycle-vs-pedestrian injuries or fatalities. Some states or municipalities might record that data though. For example: NYC’s 2021 data shows 2 pedestrian deaths from a bicycle collision, and 123 pedestrian deaths from a motor vehicle collision. But no data there on nonfatal pedestrian injuries caused by bicyclists.

A study looking at just a handful of municipalities would not be useful to draw larger conclusions. But seeing as the data collection at the national level was expressly designed to give insight into the most pressing injuries/fatalities category – those involving motor vehicles – I’m not holding by breath for expanded data collection, since bicycle-involves pedestrian collisions are at least an order of magnitude less of a problem than motor vehicle collision.

I like ebikes, but I lean towards the comments promoting plain ol bicycles as the optimal option. Simply put, a bicycle’s only requirement is a reasonably-flat surface. If nature had provided roads, it’s entirely possible for evolution to have devised wheeled creatures. For the same energy consumption, a human moves roughly four times faster or farther on a bicycle. That’s a lot of advantage for zero extra energy.

But getting back to objective requirements, the other thing working in the bicycle’s favor is the sheer number of them today: over one billion across the entire Earth, with around 100 million produced per year. If a world calamity happened right now and society collapsed, the estimated 60 million horses would become a luxury, not a utility, where 8 billion people vie for resources.

Obviously, much like a game of Catan, the horses and bicycles of the world are not evenly distributed. So if you’re going to acquire something solely to put in the bunker for a doomsday scenario, I’d suggest not putting a horse in there; they won’t like the dark.

Horses, however, have high “emissions”, in a manner of speaking. :)

That’s wonderful that children are interested in the project. This and related projects would be great to showcase at Open Sauce. I certainly enjoyed this year’s displays.

I’m not an expert with building battery packs, but I think solder isn’t a problem for connecting the nickel strips, so long as it’s only a fraction of the whole pack. And if it’s encased within the battery housing, spall won’t be as bad of a problem. The highest currents would be where the “strings” are aggregated together in parallel, and that’s usually when heavy gauge copper is used.

I recall that Aging Wheels has done videos on cell replacement, and I think maybe there was some sort of copper/brass busbar which aggregated the various nickel strips and then had large screw-down terminations for attaching external cables.

Rewatching your video again, do I understand that your emergency cut-off is inline with the full battery voltage? If your design had a smaller auxiliary 12v battery for powering the electronics, you could have a low-voltage control signal that closes a normally-open contactor that connects the main battery. Your emergency cut-off would be in-series of the control signal, so that loss of the signal immediately cuts off main battery voltage.

The same signal wire could be routed around to other safety sensors to isolate the main battery if something is wrong. In the most extreme case, the wire could be routed so that severe structural damage would automatically sever the wire.

This would also reduce the amount of heavy wire to only where it’s needed, with some weight savings. Air conditioner condensers do this same trick, so that the safety sensors don’t have to be rated for full 240 VAC.

Nice build video! I’m also a sucker for a funny unit conversion from meters/metres to burger units. And wood- and metal-working, batteries, speed controllers, motors, micromobility, and beer? Instant subscribed.

You mentioned crimping versus soldering, and I’m poised to agree, especially in a mobile application with vibrations. Although I wanted to mention another reason for crimping: in the event of an unfused, high-current short, there may be sufficient energy from the cells to instantly vaporize the solder, causing hot spall to fly everywhere, potentially combusting flammable material. For this same reason, ham radio towers will always crimp their grounding conductors in case of a lightning strike.

Have you considered cross-posting to !imadethis@lemm.ee ? Also, did you have a booth at Open Sauce?

All valid points, especially on sizing of kids bikes. For e-scooters, though, I’m not aware of there being substantially different sizes. If most public e-scooter program have only one size yet still works for a broad range of riders, then apparently fitment isn’t as big of a concern than on bikes.

This YT video by OhTheUrbanity describes the cost differences between using a public e-scooter rental for general mobility versus buying a private e-scooter outright, with rentals being more expensive. They also observed at the time – it’s a 3 year old video – that e-scooters can be purchased for CAD$800 or less. I think that’s around USD$600, and other basic models can be had for less nowadays.

Given this calculus, it seems plausible that even for households with constrained disposable income, an e-scooter wouldn’t necessarily be an extravagance and would not quickly be grown out of for a child. I personally don’t use e-scooters, but I can see why parents might consider a cheap 15 mph (25 kph) e-scooter and helmet for their child, in spite of the injury statistics, if the alternative is having to drive them around, costing gasoline and a free-range upbringing.

I can’t speak to the proportion of minors on acoustic bikes versus ebikes, but there are definitely under-18s with ebikes, in numbers ranging from “noticeable” to “common”, if I may draw from anecdotes in my area and reports from around the country.

This is a good point about data availability, and is certainly a caveat with the study. That said, I personally think legislation needs to be data driven, and when there’s a lack of available data about a given topic, the absolute wrong answer is for politicians to gesticulate wildly and give into whatever moral panic happens to be sweeping through the constituency.

It’s for this reason that I find that bills limiting minors on ebikes to be particularly pernicious.

This harkens to a Half As Interesting video (YT or Nebula) about trains being robbed at a very particular point in Southern California, between the port and the regional rail yard.

As a Euro-pallet hauler, this isn’t the most absurd implementation I’ve seen so far, as it sits low and has the rider in a recumbent position and is non-articulating. This would tend to make it harder to lose control when carrying a large payload (ie a trailer wagging across the road).

On the other hand, the lack of a direct chain, belt, or gears disqualifies this from the California definition of “bicycle”, which in turn disqualifies it as an ebike under the three class system here. If it weren’t for that, this four-wheel ebike would be legal here; other jurisdictions will vary.

But I think we need to address the elephant in the room: hauling 454 kg is well in excess of what would constitute normal bicycle or ebike traffic. A while ago, I had a thread discussing when the “micro” in micromobility ends, and I think this definitely crosses the boundary into commercial goods-hauler.

Not to say it shouldn’t exist: I can see this perfectly serving the role of last-mile delivery to restock urban shops. But this shouldn’t be ridden on bike trails or through parks, and instead should keep to street-adjacent bike lanes along existing commercial delivery routes. The benefit to distributors would be the ability to squeeze past automobile congestion. The faster-than-25-kph-version properly deserves to be regulated as an electric scooter, but the 25 kph model can plausibly coexist with motor vehicles on 30 kph (~20 mph) urban streets.

In short, if this goods-hauler can operate on existing roads and displace delivery motor-vehicles, great! But if it can only work by appropriating space on bike paths and other pedestrianized spaces, that’s not good.

I don’t think there ever will be a market-driven supply of micromobility loans, and it would have to be government subsidized to exist. That is to say, here in the USA, we should absolutely do that since I don’t expect any private lenders to do it.

If something is economically prohibitive but has clear social benefit, that’s exactly when subsidization makes the most sense. Heaven knows we already subsidize other things which have unclear benefits, but loans for micromobility would be: 1) relatively cheap, 2) easy to ascribe to individuals (eg by SSN), 3) make concrete steps toward social and climate commitments.

While that might be true for some very gnarly air speeds approaching 10-20 knots, riding out-and-back would tend to cancel out most – but not all – of the windage effects. And such winds would almost certainly be noticed as a caveat to the ride data.

Certainly, I wouldn’t recommend drawing conclusions from a few or even a single data point. It’s an ebike, so going for multiple rides shouldn’t be laborious and in-fact should be quite fun.

I’m sorry to hear about your series of unfortunate mishaps. That said, I’d be cautious about buying a second battery when you haven’t quite fully discharged the current battery. Using your existing battery is the best way to gauge what your real-life distance will be, and then you can use that figure to determine if you want the second – or maybe even third? – battery.

Most people will do a series of longer and longer rides, usually out-and-back trips. This helps get a sense for how low the battery level drops. At some point, it will be too low for “comfort” and that’s when the battery should be considered range-tested.

This “comfort” level is different for everyone, since some people only count the battery as useful if they can still hold cruise at 32 kph (20 mph). Other people might draw the line when they’re noticeably sweaty from having to help limp the bike home. Yet more people just simply look at when the battery meter moves into the red zone.

There are no wrong answers to the comfort question, but buying another battery without establishing your baseline range is like putting the cart before the horse.