everyone should realize that e-scooters are a physically risky form of transport, especially when driven above about 20km/h.
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@renardboy @rey @adub Thanks for this. I wish we could just build sidewalks to be accessible to those, since a lot more places have those then bike lanes
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*Why bicycles are surprisingly stable*
A common myth is that bicycle stability comes mainly from the spinning wheels acting as gyroscopes. Gyroscopic effects help, but they are actually not the dominant factor.
The major sources of bicycle stability are:
1. Steering geometry (trail)
• The front wheel naturally "falls into" a turn when the bike leans.
• This automatically steers the contact patch underneath the rider's centre of mass.
• The bike performs a kind of continuous self-correction.2. Large wheel diameter
• Large wheels roll smoothly over imperfections.
• Small steering disturbances produce gentler changes in direction.3. Long wheelbase
• Reduces sensitivity to perturbations.
• Creates slower, more manageable dynamics.4. Rider position
• The rider's mass is located relatively high and centred between the wheels.
• Subtle body movements can effectively influence balance.At speeds around 10-20 km/h, many bicycles are remarkably self-stabilizing. If you've ever seen a bicycle coast for a surprising distance riderless, that's evidence of these effects.
@adub it's, um, evidence of something else too...
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*Why bicycles are surprisingly stable*
A common myth is that bicycle stability comes mainly from the spinning wheels acting as gyroscopes. Gyroscopic effects help, but they are actually not the dominant factor.
The major sources of bicycle stability are:
1. Steering geometry (trail)
• The front wheel naturally "falls into" a turn when the bike leans.
• This automatically steers the contact patch underneath the rider's centre of mass.
• The bike performs a kind of continuous self-correction.2. Large wheel diameter
• Large wheels roll smoothly over imperfections.
• Small steering disturbances produce gentler changes in direction.3. Long wheelbase
• Reduces sensitivity to perturbations.
• Creates slower, more manageable dynamics.4. Rider position
• The rider's mass is located relatively high and centred between the wheels.
• Subtle body movements can effectively influence balance.At speeds around 10-20 km/h, many bicycles are remarkably self-stabilizing. If you've ever seen a bicycle coast for a surprising distance riderless, that's evidence of these effects.
@adub Isn't the self- stabilizing going away (at least in part) as soon as the rider touches the handlebar? You still need to learn to ride a bike and steer for balance.
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@LunaDragofelis i'm a big fan of my Razr kickscooter. it folds easily, has 20cm diameter wheels which go over tram tracks, and it's really nimble. a great little conveyance for all the reasons you mention. i wear a skateboarding helmet when i ride. great for up to 3km rides, for me. i haven't tried longer trips.
@adub I haven't ridden mine anymore since I gained even more weight (it's a skating tricks scooter designed for 100kg and my body is beyond 150kg now)
It has tiny wheels, but it's not really a problem if I pay attention to the ground in front of me (avoiding rocks and potholes for example). It doesn't fold, but even the few bus drivers who asked me to fold it were fine with it when I told them this model can't be folded.
It is very robust though and has very light rolling wheels so it's easy to go fast (except for my poor stamina). -
everyone should realize that e-scooters are a physically risky form of transport, especially when driven above about 20km/h. if you fall off, you're going to have facial trauma at a minimum. just ask my 50-something brother who got stuck with a big dental bill. ALWAYS wear a FULL FACE HELMET on these things - a bike helmet isn't enough. and NEVER EVER ride with MORE THAN ONE RIDER on board.
https://www.cbc.ca/news/health/e-scooters-pediatrician-survey-9.7305210
@adub
iirc, riding a bicycle is *the* most efficient way of muscle-powered movement.
And you also get versatility: You can accelerate quickly, and still coast efficiently, if you can use the gear shift properly. -
bicycles have always struck physicists (e.g. me!) as almost miraculous. they are simultaneously:
• dynamically elegant,
• mechanically simple,
• energetically near-optimal, and
• extraordinarily cheap, as a conveyance.YES I DO LOVE BICYCLES. so should everyone, tbh.
with the added proviso that not everyone can ride a bicycle and that's OK. humanity will always need other transportation options. we just aren't anywhere close to bikemaxxing yet and we should be.
@adub@beige.party I would really love a trike, or even better a velomobile, that I can ride between the mountain villages I live in. An electric assist would be great (and a requirement at my current fitness level). -
@adub@beige.party I would really love a trike, or even better a velomobile, that I can ride between the mountain villages I live in. An electric assist would be great (and a requirement at my current fitness level).@adub@beige.party I will probably end up getting an e-bike, even though I recently fell off one pretty badly because the back brake locked up because of dirt, and fishtailed me off the bike.
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@wsslmn @geonz @adub I've read articles about that before and they haven't ever addressed the issue with I've seen: freezing and refreezing. You plow perfectly and move the snow off the path. Then it warms up over the day, melting that snow and forming a lake in the path. It them freezes overnight and you've got a very smooth ice sheet.
This is why when I was biking between the two buildings at my university I stop after the first snowfall, that would happen all fall and most of the winter
@Canageek I bike year round in Southern Finland, and we get a lot of that most winters. With studded tires, I've never had any problems. Perfectly smooth ice is a joy to bike on, better than freshly laid asphalt.
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@adub
iirc, riding a bicycle is *the* most efficient way of muscle-powered movement.
And you also get versatility: You can accelerate quickly, and still coast efficiently, if you can use the gear shift properly.@libewa i mean, velomobiles (bikes with streamlined shells) do better, but those aren't available to most of us
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@libewa i mean, velomobiles (bikes with streamlined shells) do better, but those aren't available to most of us
@adub
They are essentially bikes. -
@sammallammas @wsslmn @geonz @adub Good to know! Can you ride on normal asphalt and concrete with them, or do they damage them?
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@sammallammas @wsslmn @geonz @adub Good to know! Can you ride on normal asphalt and concrete with them, or do they damage them?
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* Why e-scooters are less stable*
Most e-scooters move in the opposite direction on several of those factors.
1. Tiny wheels
This is probably the biggest issue.
• Typical bicycle wheel:
~66-74 cm diameter (26-29 inches)
• Typical e-scooter wheel:
~20-30 cm diameter (8-12 inches) if that
A bump that's trivial for a bicycle can represent a significant fraction of a scooter wheel's radius.
Consequences:
• Easier to be deflected by cracks and potholes.
• More sensitive to rough pavement.
• Higher likelihood of "catching" on obstacles.
• Faster steering reactions.
This alone accounts for much of the subjective feeling that scooters are twitchy.2. Short wheelbase
An e-scooter's wheelbase is often around half that of a bicycle.
The result:
• Quicker pitch motions.
• Greater sensitivity to weight shifts.
• More rapid response to steering inputs.
In control-theory language, scooters tend to have faster unstable modes and less passive damping.3. Higher steering sensitivity
The handlebars are directly above the front wheel.
On a bicycle:
• Hands are farther from the steering axis.
• Steering motions are somewhat filtered by body posture.
On a scooter:
• Small hand movements can create substantial steering angles.
This is one reason inexperienced riders often exhibit slight "wobbling" on scooters.4. Standing posture
Standing has advantages, but it changes the dynamics.
The rider's center of mass is:
• Higher above the deck than a cyclist's center of mass is above the bike frame.
• Less constrained by a saddle.
This means:
• Greater potential leverage on the vehicle.
• More body sway.
• More active balancing required.
The rider becomes part of the control system in a stronger way.@adub
the tyranny of tiny wheels -
bicycles have always struck physicists (e.g. me!) as almost miraculous. they are simultaneously:
• dynamically elegant,
• mechanically simple,
• energetically near-optimal, and
• extraordinarily cheap, as a conveyance.YES I DO LOVE BICYCLES. so should everyone, tbh.
with the added proviso that not everyone can ride a bicycle and that's OK. humanity will always need other transportation options. we just aren't anywhere close to bikemaxxing yet and we should be.
@adub Far more people can ride bicycles than drive cars, so no need to excuse your love!
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@dplattsf oh no, that's awful!
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@dplattsf we have tram tracks on a number of major arterials in Toronto too. i once got my bike wheel caught in a track on a rainy day and - by the grace of god or whoever - there wasn't a car to run me over from behind when i splatted. i got up very quickly but the outcome could have been so much worse!!
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@adub I'm frustrated by how much money we put into bikes. We could put that into decent transportation like a train or more buses! Things that don't involve showing up at work exhausted and sweaty and with horrible helmet hair, that don't become dangerous due to ice most of the year
Bikes are a rounding error on pretty much every budget when compared to the money put into car infrastructure.
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