[throwaway76543]

Are you thinking only of riding on roads? I often ride on paved bike trails. They're usually maybe two meters wide with mixed pedestrian and bike traffic.

Even in a bike lane you're still passing stationary objects. You asked "when would there be any" and then immediately gave one of the most common examples. An even more commmon example, of course, is the ground you're riding over. You have a 25kph speed differential to the earth.

There is no serious threat to your life from a bike going 35kph. I've crashed at that speed or faster numerous times on downhill courses. No need to be so melodramatic.

[davrosthedalek]

No, you haven't. You maybe have fallen at 35 kph. That's different. If a car hits you standing still at 35 kph, that's about the same energy as you crashing into a wall riding a bike at 35. I would not recommend it.

[throwaway76543]

I think you might be confused. We are talking about the danger involved with two bikes going the same direction with a 10kph speed differential (25kph / 35kph). When crashes like this happen, people fall off their bikes.

I mentioned that I have fallen off at this speed with relatively minor injury. People generally do not die from falling off a bike at 35kph.

Nowhere did I say anything about being hit by a car at 35kph not being dangerous. No one is saying that.

[davrosthedalek]

Actually, I think you are confused. You spoke about passing stationary objects, and you wrote you crashed at 35. I wrote that you didn't, you fell down with 35 (which you seem to concede). If you would have crashed with 35, in something hard, parked car, tree, wall of a house, or another stationary object, it's as bad as if a car hits you with 35, which indeed is very dangerous. (It's actually slightly worse, because a) the car is designed to minimize damage, and the wall is not, and b) a house is often heavier than a car, car and house building practices in the US non-withstanding)

[throwaway76543]

I spoke of the ground being a stationary object (the most common one anyone will encounter, as I put it). I did in fact fall onto the ground.

Crashing into stationary objects is indeed a much greater danger than a fellow cyclist riding with a 10kph speed differential. That was my point, which you are now re-stating.

Hope that clears up any confusion!

[gnulinux]

I witnessed a bike crash just last week (in Boston) where the convoy was biking (around ~30 kph I think) and some asshole opened his car's door without looking his surroundings, and the biker in the front bumped into the door and flew over her car. Luckily, the road was clear (so she wasn't crushed by a car) and she had a helmet. She was fine but she had a concussion. Clearly, if we were going at 25, the likelihood of she dying would be even lower, and if we were going 50, it would be significantly higher (her bike could break door's glass and she could have permanently injured herself).

I don't understand this whole thread. If you're biking in a city like Boston or SF early in the morning or around 5pm, you're trying to go office/home. What's the point of biking at 50 kph? This is not recreation. This is something I do every day and my highest priority is doing this as safe as possible. Similarly, would you drive significantly faster than speed limit with your car, because you arbitrarily think "it's not dangerous"? It's nice that you think bumping into things at 30/50 is not dangerous, I respectfully disagree and consider it absolutely dangerous and kindly invite you to stick to whatever speed limit you have in your city. People are just trying to get to their work or kids and be done with their days, please don't try to be Superman.

[throwaway76543]

Where are you getting 50kph from? Nowhere did I suggest that was a safe speed for daily riding.

We've been talking about 35kph, or 20 miles an hour, which is a perfectly reasonable speed for a bicycle. You're unlikely to be seriously injured if you crash at 35kph. People regularly ride 35kph throughout parts of their ride. It's normal, common, and entirely legal.

Your comments about "sticking to the speed limit" make no sense whatsoever. We're talking about speeds far, far below the speed limit even on residential roads.

I'm flabbergasted that you're having such a freakout over a bicycle going 20mph. I'd hate to see your reaction to an actual gas powered motorcycle or scooter.