- 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.)
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.