Laser-cut acetal (POM) chain guard

A few years ago I started playing with a laser cutter in a “maker space”, and the thing that I have had the most luck with was chain guards for my bicycles, to help keep my pants slightly cleaner.  I made one out of mirrored acrylic which looks Very Flashy, but the acrylic is not that durable.

During Covid, I lost access to the maker space, and needed a new chain guard for one off my bikes, so I went and ordered one in 3mm acetal from Sculpteo, and it has worked very well.

I don’t recall if I sent them a PDF or a SVG, but it was one of the two.

Anyhow, my chainring was creaking, some of the chainring bolts were working loose, so this seemed like a good time to take it all apart, tighten things up, and take some pictures.  Obviously the chainring needs some parts to hold it together, and these are shown here.

First, mounted on the bike.  The gap for the crank arm makes life very, very easy, compared to the aluminum ones that usually come with bicycles.  

This is my spare copy (I ordered two, shipping for two was as high as shipping for one).  Notice all the little spacers in the waste section in the center; those will be useful later.

Here is the old one, removed, with screws and washers still in place, and all the spacers in the box below.

To reinstall, use tape to hold the screws and washers in place, then put a pair of spacers (each is 3mm) on the backside.

Here I’ve tilted it the other way so you can see the spacers.

Insert the long skinny screws through the center holes in the chainring bolts, and spin the little nuts on the backside so the screws won’t come out, remove the tape, and crank them down pretty tight (because acetal is tough, unlike acrylic).

Explaining cargo bikes (mostly to other bike people)

So, I ride a cargo bike most of the time, have for about 15 years and 38,000 miles, I sometimes forget that lots of people only have experience with “normal” bikes (or worse, only with a car), and just work with that knowledge.  And I end up explaining this stuff, or parts of it, over and over again to people who think they understand what a “bicycle” is and what its “limits” are.

Laziness and convenience

I’ve long felt that I am basically lazy, and have only learned to do anything in a timely fashion because I’m going to end up doing it anyway, might as well feel virtuous for finishing before the absolute last minute. But I’ve also learned that another way to look at “laziness” is “preferring convenience” — if you want something to happen, make it “convenient”, so that “lazy” people will do it. We’re sometimes reluctant to increase convenience because it looks like “rewarding laziness”, and we all know that laziness is bad, right?

I mention this because failing to realize the importance of convenience is keeping people in cars, and out of mass transit, off their feet, and off of bicycles. This would be no big deal if cars didn’t kill thousands of pedestrians in crashes, cause tens of thousands of early deaths with their particulate pollution, contribute to global warming, and clog city streets with traffic — but they do. And since most of these problems are problems for other people and not so much us when we are driving, we still find cars to be pretty convenient, and thus use them to excess, even to the point where it affects our health and shortens our lives — we’ve made it really easy to be lazy. If we want to change this, either we have to find a way to make cars less convenient (that’ll be really popular, there’s nothing people love more than inconvenience for their own good) or to make everything else more convenient.

Consider transit. One big reason for driving a car is because it keeps the weather off. Standing by the side of the road waiting for a bus does NOT keep the weather off; if we expect people to wait for buses, there should be something to block the wind, rain, and sun. People driving get to sit; there should be a bench. It shouldn’t be optional, and it shouldn’t be regarded as “extra spending”. One problem with buses is that they’re not always reliable because they get stuck in other traffic; that can be fixed (making buses more convenient, from the point-of-view of scheduling) by giving them a reserved lane, and allowing them to trigger green lights so they don’t wait at intersections.

Or consider bicycling. There are many reasons people give for not riding a bicycle, but even someone who really wants to will be put off if it is too inconvenient. Bicycle parking should be convenient — in particular, it should be more convenient than car parking, because it’s cheaper and more compact. That means there should be so much that it almost never runs out. And because it is so compact, whenever possible it should be located close to the ultimate destination, and not in some remote corner. Ideally it’s also covered to keep the weather off, because a wet butt is Not Convenient. Yes, people can carry little seat shower caps with them and put them on every time they park their bike, but adding extra steps for people is less convenient.

It’s also possible to make walking more convenient. For cars, we have traffic sensors to ensure that green lights are triggered when someone needs to cross — nobody expects drivers to push a button for a signal. If we could have signals for pedestrians, we should, it usually happens automatically, and traffic flow is even studied to so that lights can be synchronized. Or, have you ever noticed that every traffic light everywhere always defaults to green for cars traveling in one direction or another? No matter how low the automobile traffic, the default is never for pedestrians. Such a light would be all-ways red, changing to green for cars only after one is detected.

This extends to safety devices. For whatever reason, we’ve somehow made bicycle “safety” in this country inconvenient. You’re probably already thinking, “bicycle safety, that means helmets, surely those aren’t inconvenient?” Yes, they are. Every time I go to ride my bike, I find the helmet, untangle the straps, put it on, make a vague attempt to adjust it. It almost always makes my head a little sweatier than it needs to be. When I get off the bike, I have to store it somewhere; it’s an extra step. And every summer, I sweat enough that I need to wash the helmet pads, because they get nasty otherwise. Have you noticed that car seatbelts don’t even require adjustment, that they automatically tension themselves? That’s because it was too inconvenient for people to adjust their seatbelts properly, and thus they didn’t and it was less safe than otherwise (I learned to drive in a car with aircraft seatbelts, the first time I flew in an airplane it was amusing to me that people needed instruction in how to adjust and fasten their seatbelts, I’d been adjusting seatbelts like that for years). People in cars could wear helmets — despite five-point harnesses and roll cages, race drivers wear helmets, and despite airbags and seatbelts, head injuries are a major cause of car crash death, and car crashes are a major cause of traumatic brain injury in this country — but they don’t. Helmets aren’t convenient. (Note that taking the time to answer questions about why you’re wearing a car helmet is also not convenient).

Or, “always wear hi-viz”. That’s not convenient either — it’s another piece of clothing to keep track of, it doesn’t always fit well, it can get dirty and need washing. It might not be appropriate for where you’re going, you’ll need to put it somewhere.

The safety devices I like, that I always and happily use because they are convenient, are built in to the bicycle. When I started commuting regularly, I knew myself well enough (and batteries then were needy enough) that I knew that I wouldn’t keep battery-powered lights charged, and besides, what a pain to attach your lights before every ride and then remove them at every stop, either because of theft worries, or because they needed charging. So instead I went for sidewall generators, and eventually generator hubs. If the bike rolls, the light is on, it’s a safety device that always works despite my laziness. The relatively fat tires on my bicycle are another no-effort always-present safety device. In this country we bizarrely associate skinny tires with “serious” cycling, but fat tires are better in several ways. They don’t require frequent reinflation, which is a delight to a lazy person. They don’t rely on my constant vigilance to protect the bicycle rims from potholes; within reason, they can handle whatever our town (a Boston suburb locally famous for its terrible road conditions) can dish out. Lazy people like me are not constantly vigilant. Fat enough tires don’t even fit in sewer grates or cracks in the road; again, with constant vigilance, I can be sure to hit those at an angle so they don’t grab my skinny tires, or I can just use fat tires and lazily dispense with the mandatory vigilance. (Fat tires also have lower rolling resistance, if their tread is designed for that, and since I am so lazy, that’s what I use).

My bicycle is designed for laziness convenience in other ways, too. I don’t usually use pants clips; instead I have a chain guard. Pants clips are inconvenient. Besides the lights, I tend to excess on the reflectors, because I’d rather not carry around a special piece of clothing just to be more visible. I used to use special shoes that clipped in to special pedals, but no more, it’s much more convenient to just ride in regular shoes, instead of either changing shoes at my destination, or walking around in unfashionable shoes that go click-click on hard surfaces and aren’t really that comfortable to wear all day anyhow.

I do in fact own two pairs of the funny pants, both because I raced when I was a kid, and because every year or so I ride dozens of miles in some sort of recreational event and for that distance they’re nicer than cotton underwear and pants. But I practically never wear them otherwise, because changing clothes just to ride a bicycle is not convenient.

Perhaps you think I’m crazy to be so picky about convenience, why would anyone worry about that, let along spend money on it? After all, you don’t see car manufacturers dressing up automobiles with silly gee-gaws like automatic chokes, automatic transmission, power brakes, power windows, power locks, power mirrors, power antenna, keyless entry, keyless start, remote start, air conditioning, cruise control, seat warmers, and backup cameras, do you? What sort of lazy person would want all that?

Right Hook Videos

I was trying to explain to someone on Facebook that right hooks are a problem, and a problem caused by drivers, not by people riding bicycles. No dice, cyclists are jerks for yelling at drivers when this happens, and jerks for putting their license plates on the internet, thus spake the driver. But it was a lot of work to collect these videos (seriously Youtube, can I have a “search my videos” option?) so here they are:

https://vimeo.com/111294266

https://www.youtube.com/watch?v=Ndvz4ZJRoek

https://www.youtube.com/watch?v=wNbvCgEBrLo

https://www.youtube.com/watch?v=RnHfXaYcQ08

https://www.youtube.com/watch?v=GZII3ImASVQ

https://www.youtube.com/watch?v=PJ2pe3_KClU

https://www.youtube.com/watch?v=LA3EQ4Q6avs

https://www.youtube.com/watch?v=4C6jFk3uVm8

https://vimeo.com/111805880

Doing bikes wrong the US way

Been meaning to write something, always too distracted to “do a good job”, as if getting nothing written was a good job. So….

Just now read a Copenhagenize article on bikes and trains saying something I had believed, but had no data to support. They have data. They also point out by example yet another way we do bikes wrong here in the US.

E-bike owners survey

I’m writing an article on e-bikes for the Belmont Citizens Forum,
so I need information from e-bike owners.

I don’t own one; I ride a cargo bike, so I don’t have any first-hand experience.

I’ve the questions here so that people can answer them in the comments, and so that they can send the link around to other e-bike owners.

I’m most interested in feedback from people in the Boston metro area, but feedback from other areas helps, especially if you can provide contrast with Boston (e.g., it’s hilly in West Virginia, it’s very snowy in Buffalo, it’s hot in Houston). If you prefer not to answer in the comments, you can mail them to me at dr2chase@mac.com.

1. What motivated you to try an e-bike? Was a hill too steep, or a commute too long, or were kids too heavy, or did you need to arrive at work not too sweaty?
2. Have you had your bike for long? Is it reliable?
3. What kind of bike is it? (for example, Pedego, Specialized, or some brand of electrified cargo bike?)
4. Can you describe how you use your e-bike? That is, do you ride for fun, or for commuting and errands? Do you ride every day, once or twice a week, or less often? Are there hills or long distances involved? Do you carry heavy loads, or children?
5. How does the e-bike help this?

• May I use your name or initials in the article?
• May I describe your situation in some detail, rather than general terms?
  For example: “AR commutes year-round from a steep hill in Belmont to Kendall Square in Cambridge, carrying two small children in a ButchersAndBicycles tricycle to drop off at day care along the way”

Thanks you for your time. If you would like a copy of the article, please mention that in the comments or email.

Hypothesized mechanisms for US safety in numbers

Hypothesized mechanisms for “safety in numbers”

Safety in numbers is a cycling safety rule that says that the more people ride bikes, the safer each rider will be. Hypothesized mechanisms include (1) driver familiarity – because drivers more often see bikes on the road, they become better-trained to see them on the road and (2) driver empathy – because so many drivers also ride bikes, they are more aware-of/concerned-about bicycle safety issues. (Here’s a nice pile of pointers to papers, tracked down by a real live researcher.)

I think both of these mechanisms are entirely possible, but riding an actual bike in actual traffic in actual crowds of cyclists, I’ve noticed what looks like other ways that greater numbers provide safety. In at least one case I’ve captured it on video. The difference between these mechanisms and the others that are hypothesized is that they are extremely short term – “safety in numbers” can appear whenever there is a biking crowd and disappear as soon as it disperses. These are also somewhat more likely in crowded urban areas and depend somewhat on the existence of traffic jams.

The first mechanism I might call “schooling” (after Bike Snob’s “shoaling” and “salmoning”). Bikes riding in a line are schooling, and for several common cycling hazards, most of the risk is borne by the lead fish, and the rest get a free ride. If someone in a parked car is not looking for bikes and is about to open their door, but then a bike zips by, it’s not unreasonable that they would be startled, and maybe then look to see if it was clear – and if the bikes are schooling, all the followers get the benefit of that. The dooring risk is almost entirely on the lead cyclist. Similarly, cars pulling into or across traffic represent a threat only to the lead cyclist, and very little to the ones in the rear. A line of bikes is also somewhat protective against right hooks, since those usually occur when a driver thinks they can overtake a bike and turn right, or forgets the presence of a single bike. With a line of bikes, once the first is across the side street, it is obvious to the driver that a right turn is not possible.

A second method is less obvious, but safety decreases markedly in the range of speeds between the slowest and fastest typical commuters. A low-speed (below 10mph) crash is stupidly survivable; you can almost step off your bike as it falls down. A high-speed crash (above 20mph) is far more likely to send you to the hospital or worse. Bike lanes at rush hour tend to run single file for some distance, usually because the bikes are hemmed in between parked cars on the right and “parked” cars on the left. Inevitably, some riders will be slower than others, and the inability to pass then compels the would-be-faster riders behind to slow down until they can pass. This makes them safer, whether they like it or not. This, I’ve seen on video, where I play the role of impatient rider. The probability of this delay and the difficulty of passing both rise pretty quickly once there’s more than a couple of riders delayed behind a slow leader.

After dark, a school-of-fish also multiplies the effectiveness of any lights that cyclists might be using. Just considering use of lights and not, if an unlit cyclist pairs up with one using lights, they can obtain most of the safety benefit of the lights. When two cyclists both have lights, the variations in their movement or in the flashing style of their different lights will create additional visibility over a single cyclist; for example, one cyclist’s flashing light might draw attention, but the other’s steady light might allow a driver to accurately locate the pair. Not nearly as many cyclists ride at night, but bicycle lighting use in the US is not nearly as good as it should be, so there’s plenty of room for this to help.

I don’t know if I’m typical, but if I’m riding at night and overtake another cyclist without lights who’s not too much slower than me, I’ll slow down to give them the benefit of my lights. I’ve even done this with a (impressively fast and competent) rollerblader caught by the late-fall early sunset on the local multi-use path.

The interesting (to me) thing about these is that they can work in the US, they take no time to work, and they take no change in driver empathy or enlightenment. And if a crowd of bikes disassembles, then the safety effects do as well. The effects should appear most often at rush hours, when the largest number of bikes are on the road and when they are most hemmed in by traffic.

A historical/hysterical note is where the idea for safety-in-numbers comes from, and why we assume its existence even when we’re not entirely sure how it works. Once upon a time, when Effective Cyclists were peddling their prescriptions for safer cycling (ride in the road, in traffic, just like the “vehicle” that bicycles legally are, and that legal status is a good thing for which the EC movement certainly deserves some credit) the counterexamples of “the Dutch” and “the Danes” came up, where many people often ride bikes on lanes entirely separate from auto traffic, with crash fatality rates 5 times lower than ours. The EC people were very good at finding and/or interpreting studies that “proved” that if only the Dutch would get rid of their separate facilities, they would be even safer than they are now, that in fact their extraordinary safety must have some other cause. (This might even be true, but nobody’s ever managed to get more than about 1% of the population to bike in an “Effective” style.)

And what was the obvious difference that might be the cause of that anomalous safety? “Numbers”. It must be “Safety in Numbers”, assumed to exist to fill a (huge) gap between theory and reality. This was convenient for the Effective Cyclists because they got to continue to feel correct about their prescriptions (“just you wait, once everyone here rides bikes, we’ll be the safest cyclists on the planet!”) but now this same hypothesized mechanism is used to justify creation of cycling-specific infrastructure that Effective Cyclists hate (“we’re tired of waiting, EC is phenomenally unpopular and we’ll never get the numbers that give us the safety we want if we do it your way. And by-the-way, global warming, particulate pollution, pedestrian deaths, urban congestion delays, traffic noise, and public health, we need this now. Infrastructure will get butts in saddles and safety-in-numbers ‘proves’ that they’ll be safe.”)

Cars as Sensory Deprivation Chambers

I both drive cars and ride bikes, and for years I didn’t think much about how much driving a car impairs all your senses, as well as your ability to communicate. To hear how other people talk about traffic and safety, I think I’m not the only person to miss this.

Where this usually comes up is in discussions of rolling stops, and stop-then-go at red lights. The claim from cyclists (and this claim is absolutely true, which is why I’m writing this) is that they generally can see and hear better than people in cars, and thus are in a better position to judge if it is safe to go or not. This is one of the several justifications for the Idaho Stop Law.

So, vision. Someone riding a bike is as tall as they are standing up, if not taller. To stop, most people must hop off the saddle because they sit too high to reach the ground with their feet. Modern sedans tend to be about 4-and-a-half-feet tall (I just measured a Civic and a Camry), so whoever is sitting in them is shorter than that. On a bicycle, seated, your head is about 3 feet back from the front edge of the bicycle, but it’s easy to lean forward to within about a foot of the front. In a car, leaning forward gets you to the windshield, which is five feet back from the front of the car. Add to that whatever fog or dirt happens to be on the windshield and the windows, plus the various pillars and mirrors and fuzzy dice, and I hope it’s clear that the cyclist has a far better view of what’s around.

Next, hearing. Luxury cars are actually marketed for their ability to make you deaf to the world. That ought to be enough right there, but I’ve actually mentioned this to a degreed+prestigious colleague whose snap reaction was “no, I can hear okay in a car”. No, really, you can’t. Even without luxury soundproofing, cars have noisy engines, ventilation fans, tire noise, often a stereo, and quite often their windows are up. All these things act to block exterior sound. On a bicycle, the default is that you hear everything. There’s wind noise when you’re moving, but stopped at an intersection there’s nothing between you and the world and the bike is silent.

And you might like to think that maybe hearing doesn’t matter–after all, we let people who are deaf drive and ride bikes–but it certainly does. When I approach intersections, I can hear cross traffic coming before I can see it; that’s redundant safety information, which is a good thing. I can hear cars approaching from behind, and tell if they’re slowing or swinging out into traffic to pass, and I can judge the size of the car or truck as well (big trucks without sideguards are very dangerous). For pedestrian safety being able to hear matters, because I can carry on a conversation with the people around me. “I see you”, “go ahead, it’s a crosswalk, I’m stopping”, and of course “oops, sorry”. I can communicate with other cyclists, “there’s a blind woman walking ahead of you” (in the dark). All the sound signals that we’re supposed to legally make when approaching pedestrians are useless when approaching cars because drivers are effectively deaf. All the communication that’s easy with people around us is impossible with people in cars.

People on bikes also see more because of their ability to always position themselves near an intersection before stopping. That means we always get to see the light cycles and light timings, and even if we haven’t learned them all yet ourselves, we can see how other cyclists react to them. We don’t need to catch sight of landmarks as we drive through the intersection, because we always have plenty of time to look around at the front. Once you know the usual timing for a light (easily derived from countdown pedestrian timers on the street and cross street – which you can see because you are stopped at the intersection) you can also judge from quite a distance the appropriate speed to make the next light, which allows you to moderate your speed to only what is adequate to catch the green. Lower speeds make for easier pedalling, and are also safer.

I had meant to make a much longer rant about “windshield vision”, but I think this is good enough for a start. You might ask yourself, if you could drive and fool yourself into thinking that you weren’t half-blind and mostly-deaf, and not realize what you were missing stuck back in a line of traffic, if you might not be self-fooled about some other things. If your reaction to the facts stated here is that they’re the crazy opinions of one of “those cyclists” – don’t forget, I am a licensed driver, I drive often enough, I own a car, and this is true of most adults riding bicycles (knowing this stuff makes driving a lot less fun. Don’t expect any auto advertising to mention this ever).

Bonus sensory deprivation video, in case you still don’t believe me: watch the second driver in this video roll right over a bicycle and a bicyclist’s foot, and not be able to believe she did it. Said bicyclist has right of way, in clear daylight, riding straight on a straight road, wearing a dayglo-yellow jacket, with a front flashing light. The second driver did not see, did not hear the crash, did not hear the crunch of the bike as she drove over it, did not hear the guy she was running over yelling at her.

It occurred to me a few days after posting this that “people on bikes behave unpredictably” is consistent with “people on bikes make decisions based on information I don’t have”. Probably not the only explanation, but worth thinking about before jumping to pejorative conclusions.

Parcel delivery robots

I was thinking about how we would deliver goods in a hypothetical ban-cars world, and realized that people on bicycles carrying stuff are not a bad model for what robots might also deliver on vehicles of modest size. Because we don’t normally see huge deliveries on small vehicles we tend not to think that it’s possible, or even when we do see it shuffle it into the ignorable category of “crazy”. But it is possible and it happens, whether we believe it’s “crazy” or not, and if you want to think about what a small robot vehicle might be capable of, it helps to remember that a human is a somewhat idiosyncratic 250 watt motor, and that a robot running a 250 watt motor and carrying 100lbs of batteries has similar capabilities.

So, what can humans carry on bicycles?

Haley Trike and 400 lbs of sand (video)

a chicken coop

a trailer full of Citibikes

a ludicrously large pile of stuff

a mattress, table, chair, and box

People carrying that much stuff don’t move very fast, but they move, and there’s no particular reason for a robot to travel quickly either; there’s no driver being paid by the hour, and it reduces the risk and severity of any possible crashes.

Today’s Bad Driving

First, we start with someone who is doing something that requires two hands on the smartphone, surely not texting, that would be illegal:

Notice how the Prudent Cyclist is none too eager to pass this person after noticing their unpredictable and erratic driving.

Next, we have someone piloting their barge down the Broadway Ship Channel, and they have inadvertently strayed outside the marked boundaries.  Remember boaters, “Red, Right, Return”.