In summary, Denver’s ebike rebate experiment was inspired by utility rebates from other regions, was stupendously successful, flattered by emulation in other jurisdictions and the State of Colorado itself, to the point that the city might recast its program to equitably incentivize low-income riders, as well as focusing on other barriers to riding, such as poor infrastructure. The experiment has paid off, and that’s before considering the small business boost to local bike shops and expanding the use of ebikes for transportation in addition to recreation.

With that all said, I want to comment about the purported study which concluded that ebike rebate programs are less economically efficient than electric automobile rebates. Or I would, if the study PDF wasn’t trapped behind Elsevier’s paywall. I suppose I could email the author to ask for a copy directly.

But from the abstract, the authors looked to existing studies which originally suggested that ebike rebates are less efficient, so I found a list of that study’s citations, identifying two which could be relevant:

• E-bikes and their capability to reduce car CO2 emissions (Phelps et al, 2021, open access)
• Impacts of e-bike ownership on travel behavior: Evidence from three northern California rebate programs (Johnson et al, 2023, open access)

The first study looked at ebikes in England – not the whole UK – and their potential to displace automobile trips, thus reducing overall CO2 emissions. It concluded that increased ebike uptake would produce emissions savings faster than waiting for average automobile emissions to reduce, or from reductions in driving by other means, as a means to slow the climate disaster. This study does not analyze the long-term expected emissions reduction compared to cars, but did conclude that ebikes would produce the most savings in rural areas, as denser cities are already amenable to acoustic cycling and public transport.

The second study looked at a year of how new ebike owners changed their travel behavior, for participants from three California jurisdictions offering incentives, two in the San Francisco Bay Area and one along the North Coast. The study concluded that in the first few months, most riders used their ebike 1-3 times per week, but towards the end of the study period, most riders reduced their use, although the final rate was still higher than the national average rate for acoustic bicycling. The study found that at its peak, ebikes replaced just a hair above 50% of trips, and thus concluded that the emissions saved by displacing automobile trips was not as cost effective as emissions reduced through EV automobile incentives. They computed the dollar-per-co2-ton for each mode of transportation.

So it would seem that the original study looked to this second study and reached a similar conclusion. However, the second study noted that their data has the caveat of being obtained from 2021 to 2022, when the global pandemic pushed bicycling into the spotlight as a means of leaving one’s house for safe recreation. It would not be a surprise then that automobile trips were not displaced, since recreational bicycle rides don’t compete with driving a car from point A to point B for transportation.

Essentially, it seems that the uncertainty in emissions reduction is rooted in variability as to whether ebikes are used mostly for recreation, or mostly for displacing car trips. But as all the studies note, ebikes have a host of other intangible benefits.

IMO, it would be unwise to read only the economic or emissions conclusion as a dismissal of ebikes or ebike rebates. Instead, the economics can be boosted by focusing resources for rural or poorer riders who do not have non-automobile options, and the emissions savings can be bolstered by making it easier/safer to ride. Basically, exactly what Denver is now doing.

I get that the weight pales in comparison to the rider or cargo. But a lighter bike – electric or otherwise – comes with some quality of life improvements. There’s the extra redundancy where a dead ebike is still ridable if it’s light enough or has sufficiently low rolling resistance. Then there’s transporting the bike, whether by bus, car, or just hitching a ride if the bike is dead or damaged.

My experience at university – where an ebike would have been phenomenally useful back then – involved hauling my acoustic bike up two flights of stairs daily. At 15 kg, that was doable. 25 kg is starting to push things. And my current ebike at 40 kg would be infeasible unless I decide to really work on my deadlift.

But I agree that there’s a point where ebikes are Good Enough™ given the constraints of technical and economic feasibility, as well as what consumer demand looks like; all consumer products tend to do this. We’ve reached an equilibrium in the market – which isn’t bad at all as it means more bikes available to more people – but I just hope the industry continues to push the envelope to welcome even more riders.

Someone out there will have all the preconditions for a short/medium distance ebike commuter, where they can replace a car drive or waiting for three buses, down to just a single bus and a modest ebike ride to their final destination.

Irrespective of the model variant chosen, the weight is stated as 26 pounds or 12 kilograms. Such a low weight can only be achieved, particularly on an e-bike, with a carbon frame, and the fork is also made of the material.

Is this actually true though? I’m not a mechanical engineer, and while I do know that material properties necessarily influence the realized design, I can’t quite see how swapping out an aluminum or steel frame for a carbon fiber frame is going to save any more than maybe 2-5 kilograms max.

My cursory examination of the popular ebike models suggests the current average weight is around 25 kilogram. I would posit that the higher weight for run-of-the-mill ebikes compared to this €5800 model is more likely due to: 1) overbuilt, stock frame designs in errant anticipation of offroading or hitting potholes faster than an acoustic bicycle would be subject to, 2) a lack of market demand for pushing the weights down, since the motor can compensate for the loss of performance, and 3) if a bicycle of any type is going into the mid four figures, of course it would use premium, lighter components than other cheaper manufacturers.

What I’d love to see is a teardown of a commercially available $2k range ebike to see how much the frame really weighs. The motors and batteries can’t really be reduced without substantial electrical or chemical engineering, but frame design is well within the remit of bike manufacturers, and I think it behooves them to not overbuild the frame. Ebikes deserve to be equally hauled up a flight of stairs, or onto a bus, or just onto a bike stand. And it’s not like acoustic bikes can’t get up to ebike speed going downhill, and their frames generally hold up just fine.

To be clear, I’m mostly talking about conventionally shaped bicycles versus conventionally shaped ebikes. It would be apples to oranges to suggest that a cargo ebike should weigh only as much as an acoustic commuter bike. For a cargo bike, payload capacity is a major consideration and so would warrant an appropriately sized frame. But the weight discrepancy between an equally capable cargo bike and cargo ebike should not exceed that of the motor, battery, and ancillary components.

For example, with all things being equal, you can very easily see if a certain wheel is creating more resistance over another.

But this product cannot compute drag figures for the bike. Its theory of operation limits it to compute only the drag upon the rider. Also, to keep things simple in my original answer, I didn’t touch upon the complex bike+rider aerodynamic interactions, such as when turbulent air off the bike is actually alleviated by the presence of the rider, but thus moves a net-smaller drag from the bike onto the rider. Optimizing for lowest rider drag could end up increasing the bike’s drag, inadvertently increasing overall drag.

But I think the real issue is the “all else being equal” part. If a team is trying to test optimal rider positions, then the only sensible way to test that in-field is to do A/B testing and hope for similar conditions. If the conditions aren’t similar enough, the only option is more runs. All to answer something which putting the rider+bike into a wind tunnel would have quickly answered. Guess-and-check is not a time-efficient solution for finding improvements.

Do I think all bike racing teams need a 24/7 wind tunnel? No, definitely not. For reference, the Wright Brothers built their own small wind tunnel to do small-scale testing, so it’s not like racing teams are out of options between this product and a full-blown (pun intended) wind tunnel. And of course, in the 21st Century, we have a rich library of shared aerodynamic research on racing bikes to lean on, plus fluid modeling software.

My initial reaction was “this cannot work”. So I looked at their website, which is mostly puffery and other flowery language. But to their credit, they’ve got two studies, err papers, err preprints, uh PDFs, one of which describes their validation of their product against wind tunnel results.

In brief, the theory of operation is that there’s a force sensor at each part where the rider meets the bike: handlebars, saddle, and pedals. Because Newton’s Third Law of Motion requires that aerodynamic forces on the rider must be fully transfered to the bike – or else the rider is separating from the bike – the forces on these sensors will total to the overall aerodynamic forces acting on the rider.

From a theoretical perspective, this is actually sound, and would detect aero forces from any direction, regardless of if it’s caused by clothes (eg a hoodie flailing in the air) or a cross-wind. It does require an assumption that the rider not contact any other parts of the bike, which is reasonable for racing bikes.

But the practical issue is that while aero forces are totalized with this method, it provides zero insight into where the forces are being generated from. This makes it hard to determine what rider position will optimize airflow for a given condition. To make aero improvements like this becomes a game of guess-and-check. Whereas in a wind tunnel, identifying zones of turbulent air is fairly easy, using – among other things – smoke to see how the air travels around the rider. The magnitude of the turbulent regions can then be quantified individually, which helps paint a picture of where improvements can be made.

For that reason alone, this is not at all a “wind tunnel killer”. It can certainly still find use, since it yields in-field measurements that can complement laboratory data. Though I’m skeptical about how a rider would even respond if given real-time info about their body’s current aerodynamic drag. Should they start tacking side to side? Tuck further in?

More data can be useful, but one of the unfortunate trends from the Big Data explosion is the assumption that more data is always useful. If that were true, everyone would always be advised to undergo every preventative medical diagnostics annually, irrespective of risk. Whereas the current reality is that overdiagnosis is a real problem now precisely because some doctors and patients are caught in that false assumption.

My conclusion: technically feasible but seems gimmicky.

“Not everybody can use a bike to get around — these are some of our major arterial roads, whether it is Bloor, University or Yonge Street — people need to get to and from work,” Sarkaria said.

This is some exasperatingly bad logic from the provincial Transport Minister. The idea that biking should be disqualified because the infrastructure cannot magically enable every single person to start biking is nonsense. By the same “logic”, the provincial freeways should be closed down because not everyone can drive a car. And then there’s some drivel about bike lanes contributing to gridlock, which is nonsense in the original meaning and disproven in the colloquial meaning.

It is beyond the pale that provincial policy will impose a ceiling on what a municipality can do with its locally-managed roads. At least here in America, a US State would impose only a floor and cities would build up from there. Such minimums include things like driving on the right and how speed limits are computed. But if a USA city or county aspires for greatness, there is no general rule against upgrading a road to an expressway, or closing a downtown street to become fully pedestrianized.

How can it be that Ontario policy will slide further backwards than that of US States?

My literacy of the German language is almost nil, but it seems patently unreasonable for an author or journalist to believe that over half of the incidents involving a fairly common activity would be fatal. Now, I should say that I’m basing this on prior knowledge of the German e-bike/pedelec market, where over half the bikes sold there at electric. What this implies is that of the sizable population of the country, of the subset which are riding bicycles, and further the subset which ride pedelecs, and still yet the subset which get into a collision or other incident, that somehow it’s believable that over half will die?

That cannot possibly be true, does not pass the sniff test, and isn’t even passable as a joke. If it were true, there would be scores of dead riders left and right, in every city in the country, daily. I suspect it would overtake (pun intended) the number of murders in the fairly safe country.

Compare this with parachuting, which would be more sensible for a headline of “most accidents are fatal”, I’m shocked that no one in the publication chain of command noticed such a gross error. While it’s true that some statistics are bona fide shocking – American shooting deaths come to mind – this is a very bizarre instance of confirmation bias, since no one noticed the error.

I was led to believe that cycling in German is “normalized but marginalized”, but this type of error speaks to some journalistic malpractice.

I think you’re spot on, since using a random power/torque/rpm calculator online, an 85 Nm mid-drive motor rotating at a reasonable crank cadence of 80 RPM yields a power output of 710 W. That’s just shy of the max power regulation in the USA for ebikes, at 750 W. And motors can definitely go faster than 80 RPM.

Mid-drive motors could probably be built with even more torque, but because electric motors maintain near-constant torque through most of their RPM range, the motor controller would have to perform more current limiting at the higher RPMs to stay under the legal power limits. So there’s less benefit, unless someone really badly wants more low-RPM torque.

At that point, though, other parts of the bicycle drivetrain might start disintegrating under such forces.

You may want to include a photo of the piece, ideally many photos from various angles.

But to be frank, unless you find someone within a max 1 hour’s travel distance, it’s not likely someone will be found who is also willing to take on this project. Wood furniture is, for all its pros and cons, heavy.

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.

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?

I know this is c/programmerhumor but I’ll take a stab at the question. If I may broaden the question to include collectively the set of software engineers, programmers, and (from a mainframe era) operators – but will still use “programmers” for brevity – then we can find examples of all sorts of other roles being taken over by computers or subsumed as part of a different worker’s job description. So it shouldn’t really be surprising that the job of programmer would also be partially offloaded.

The classic example of computer-induced obsolescence is the job of typist, where a large organization would employ staff to operate typewriters to convert hand-written memos into typed documents. Helped by the availability of word processors – no, not the software but a standalone appliance – and then the personal computer, the expectation moved to where knowledge workers have to type their own documents.

If we look to some of the earliest analog computers, built to compute differential equations such as for weather and flow analysis, a small team of people would be needed to operate and interpret the results for the research staff. But nowadays, researchers are expected to crunch their own numbers, possibly aided by a statistics or data analyst expert, but they’re still working in R or Python, as opposed to a dedicated person or team that sets up the analysis program.

In that sense, the job of setting up tasks to run on a computer – that is, the old definition of “programming” the machine – has moved to the users. But alleviating the burden on programmers isn’t always going to be viewed as obsolescence. Otherwise, we’d say that tab-complete is making human-typing obsolete lol

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?