I have to say I'm a bit puzzled with all these responses essentially saying "I manage to do it without too much difficultly, therefore it must be safe". Driving a car while drunk isn't that difficult to do either, but that doesn't mean it's safe.
Really? I find it difficult to drive when I'm tired, and being drunk gives me similar difficulties doing everything else. I suppose I've just assumed that driving drunk was pretty difficult. Isn't that why we're not supposed to do it?
Difficultly has absolutely nothing to do with it. The point is not whether or not one can manage to simultaneously operate brake levers and steer. The point is that when your reflex and coordination abilities are pushed to the limit by an emergency situation it's best to have all essential operations as easy as possible. Not, easy enough under most circumstances, but as easy as possible. Not sober enough to manage driving with practice, but eliminating all potential difficulties by being as sober as possible.
So you're concerned that your hands and arms can't handle steadying and minorly directing the handlebars while squeezing the breaks? You should watch kids play video games. I really don't think this is too taxing for the appendages in question or our reflexes.
The beautiful thing about the human reflex system is the way it sort of abstracts things for you. After years of martial arts as a kid it really is amazing how your muscles go from the movements you're used to to a complex strike being a thoughtless operation. I imagine the same sort of thing happens in cycling. Your muscle memory probably knows a surprising amount about how to brake and steer. So doing both at the same time becomes not only possible but easy.
Depending on skills that must be learned with practice in emergency situations is a recipe for disaster. When the adrenaline starts pumping, learned practiced skills go out the window and basic instincts take over. For example, when most people get angry they start talking in their native accents. Practice can not help and, therefore, all essential functions necessary to survive emergency situations should be as easy and instinctual as possible, which means that you shouldn't need to use your hands to do multiple jobs.
This isn't correct. You're contradicting a thousand years of martial arts and other related things which depend on, quite literally, learned reflexes. Driving is probably one as well, and so is the most basic act of balancing a bicycle.
I don't think speaking differently when you're angry has anything to do with reflexes. It probably has to do with the way the brain forms different centers of speech for different situations.
Of course you don't need to grip the bars to steer. You can steer with your elbows while holding a pizza, but that doesn't make it the safest way to ride.
But the pizza tastes so yummy.
Which is exactly why it's a bad idea to either commit your hands to braking by putting them over the brake levers or commit them to steering by putting them under the brake levers. Using different extremities for braking and steering allows you to switch between the two more quickly, but if you are stuck being committed to one and can't switch fast enough then you might be tempted to do both simultaneously because you can't do either one with the necessary precision.
I still don't get this. I brake by squeezing the levers. I don't steer by pulling the handlebars or pushing the handlebars (at least not consciously). And I have never had a problem keeping the bike under control with maximum pressure on the brakes (maximum defined by as much as I can do without the bike and I exchanging positions of authority).
Steering your bike with your body's balance is steering with your hands. Your body weight rests on your butt, your feet, and your hands. So to change your body's balance you need to use your butt your feet and your hands. Now, since your butt isn't very maneuverable and your feet are resting on cranks which are unstable due to freewheeling, your hands are your best option....unless of course they're too preoccupied with the brake levers.
No, that's not how you shift your balance. Sit in a chair and hold up your hands high in the air. Then lean each way. Now hold your hands together in your lap. Lean each way.
If you used your hands (literally) to shift your balance on the bike you would steer in the opposite direction you leaned. Here's what happens:
1. You push with your right hand to shift your center of gravity to the left.
2. This happens, at the same time you turn the wheel to the left (your right hand moves forward because it's putting more force on the handlebars than the left).
3. This causes counter steer -- Your bike turns to the left then leans to the right abruptly and begins turning right.
This is the only way one can turn a motorcycle (according to wikipedia) because of the weight of the vehicle. But on a bicycle you can just lean (you do weigh 10 times as much as the bike which is on 1/2" to 2" tires).
I'm just asking the question of whether or not handbrakes are dangerous. The lack of safe alternatives is another discussion.
No, they're fine. You're listening to dozens of cyclists telling you we feel we have maximum stopping power and control with them and would not prefer a pedal based alternative.