- cross-posted to:
- [email protected]
- [email protected]
- cross-posted to:
- [email protected]
- [email protected]
(Title shamelessly stolen from this comment in the crossposted [email protected] thread.)
(Title shamelessly stolen from this comment in the crossposted [email protected] thread.)
How many people can really control a bike at 28mph?
I have a Class 3 (28mph), it’s actually not too bad. That assumes the brakes are well-maintained, though, and as we know there are no inspections for e-bikes. I’ve seen some terrifyingly bad brakes on normal bicycles, so I can’t imagine what some people’s e-bikes look like.
It should be mandatory for Class 2 and Class 3 e-bikes to have hydraulic disc brakes imo. I have mechanical disc brakes, and I have to tighten them at least once a month. It seems unwise to trust that the average person would also do that. Rim brakes are right out; they have nowhere near enough braking power for the speed and weight of most e-bikes.
So, are you insured in case you run someone over?
Most people that do longer rides would be fine with that. On downhill sections you can hit that easily enough, and there’s wind too. It’s definitely fast, but it’s fine enough. It doesn’t matter what you’re driving or riding, you always drive to the conditions anyways.
Yes, you can easily get that fast, but can you also brake fast and reliably enough, too, so humanity is safe around you?
If you agree that humans can control a car going 75mph, then a bike going 28 isn’t an issue.
Yes, but a car has actually appropriate brakes for the speed they are going at. With bikes, even good brakes are not really up to such speeds.
Go ride a bike… Grab the left brake as hard as you can. You will change your mind.
I did way more than 1000km/month on my bicycle back in my time. I know what happens when you are stupid enough to break with the front wheels only. Even with disk brakes on both wheels you don’t have enough contact with the ground to ride at such speeds in a traffic-safe way. That’s why I object to the idea that a bike with 28mph would be safe, and would definitely require insurance for such a vehicle.
https://www.omnicalculator.com/physics/stopping-distance
https://www.webpages.uidaho.edu/niatt_labmanual/chapters/geometricdesign/theoryandconcepts/BrakeReactionTime.htm
Stopping distance in a car is therefore 140.22 ft.
Do you think that you can’t do equal or better on a bike?
Any situation that you believe a car can do safely, there’s no reason to believe a bike couldn’t either. FFS we have these wonderful things called motorcycles. Much less contact with the ground [than a car], much higher speeds. Works just fine.
If you look at that page carefully, it gives the full formula for the brake distance. And assumes a factor of f=0.7 for an average car.
The AASHTO gives a factor of f=0.25 for a bike. Which means: Yes, there is a difference.
The f for a motorcycle is somewhere in between, but nearer to the .7 than the .25.
The braking characteristics are not all that different from a normal bike to an ebike, provided they weren’t deliberately ignored. Ebikes having a lower centre of gravity also helps this. If you want to whine about ebikes going 28m/h, you should also be complaining about 80% of the cyclists out there.
That’s the point. That’s what makes them dangerous.
And: If cyclists only did 28 meters per hour, they would actually be quite safe :-)
I feel like you’re missing that the brakes on current (decent/non-shit) bikes are quite satisfactory. And that cyclists normally dont ride at 28mph, unless going downhill. And that regardless of vehicle, it is up to the rider to be safe for the conditions.
It is not the brakes as such, but braking, which has a number of factors. One key factor is friction between wheel and surface. Your brakes might bring your wheels to a quick standstill, but that might not stop the bike.
And the 28mph stem from the point that there are electric bikes that go up to that speed.
Yes, locking up your wheels is bad. The same is true on a car. It is good that on small mechanical systems with feedback, it is easy to not lock up the tires.
On top of that, many ebikes have regenerative breaking, which makes it easy to maintain a good speed.
I ride a class 3 and 30mph is not that bad. I regularly hit that coming down hills, even on a non-ebike. It does require your attention to be on the road and it would hurt if you wiped out. My fastest ever was 44mph
What is a “class 3”? Is that an American classification?
Its largely by state here in the US, but it is kind of staring to converge on similar guidelines.
In Colorado
Class 1: The electric motor provides assistance only while the rider is pedaling and stops assisting at 20 mph.
Class 2: The electric motor can propel the bike without pedaling, but stops assisting at 20 mph.
Class 3: The electric motor provides assistance only while the rider is pedaling and stops assisting at 28 mph.
All must be less than 750 watts, but it doesn’t specify how that is measured. Also, these rules aren’t reliably enforced.
My city just has a 20mph limit on urban trails and tolerates ebikes that don’t do stupid stuff and ring their bell for peds.
Thanks. How far does it take you to brake down from top speed to standstill?
I’ll run a test at some point. Definitely faster than a car, but my bike has nice brakes. Not every cheap Chinese budget bike is going to have these brakes.
Also, because my ebike is relatively light/average, there is a “wind wall” at around 20 mph where aerodynamics become more effective than pedaling. Sitting up and stopping pedaling when I’ve been hunched over pushing hard will quickly bring me back to 15-20 mph. I don’t know where this wind wall is on a heavy ebike with fat tires, a heavy rider, and a rack full of luggage.
To the point of braking for pedestrians, on paved trails, I always ring my bell until people acknowledge me in some nonverbal way and I slow down for dogs because they can be startled by fast bikes. I’ve had many peds thank me for ringing the bell on a trail and I’m convinced if everyone did it, 2/3 of the bike/pedestrian animosity would instantly dry up.
Cars don’t care around here. They only see their phones, traffic lights, and the back of the car in front of them.
That’s what they say about bikers (especially electrical) here in the pedestrian zone and the sidewalks, too.
Odd, may I ask about your approximate geography? My area is very suburban and bikes mix with peds better than cars here because most of our streets are 6 lane roads with 40-55 mph speed limits. (45-70 mph actual speed) If the speed limits were 25-35 mph I would probably ride on the road a lot more.
Central Europe. Most roads in the city are narrow two-lanes, a few main roads have four or even six lanes. Mayor just sacrificed two of the four lanes of one of the main arteries of the city center to bike lanes which are only sparsely used. Extensive pedestrian zone in the city center.
Car speed limits are 35mph in the city, with select roads limiting to 20mph.
Honestly the motor should be cutting off well before that speed.
Yes. Way before that.