Emergency Stopping
 

What do you do?

I had to do one the other day and ended up locking both wheels and skidding to a halt about 2ft behind they car. I presume using my breaks a bit better would have probably helped somewhat, but how much does that actually work if you really have to stop stupidly fast?

I have posted this further down, but the whole thread rarely gets read (I know I don't quite often), but I do know how to break. As much as anything I'm curious as to what has happened to you when you've been in the type of situation where you stop fast or see the underside of a car.

Another option is to the steer around the object that is stopped.

Better off using your brakes!

I practice panic stops every once in awhile; sometimes to be cool, sometimes to know how the bike will react.

I bailed out into a rosemary shrub the other day when a father teaching his very young son how to ride a trike got in my way despite my approaching them at the very minimum speed required to remain upright. (On a street w/a cul-de-sac and a gated ramp into a park with paths leading to major streets.) I think the kid got distracted by the shiny bike and just drifted over and stopped right in front of me. You do whatcha gotta do. Of course, this wasn't a panic stop so much as a bemused slapstick stop.

In terms of real panic stops, this Sheldon Brown page might be helpful reading.

First thing I'd advise is to take the earplugs out and keep your eyes on the road at least 50 yards before any emergency.

Who mentioned earphones? Or did you just stop in to grind your axe?

When you have to stop stupidly fast?

Apply brakes. Hope for the best.

To the OP, practice in a parking lot. Learn your stopping distances.

How much difference does feathering your barkes make compared to just locking both wheels, kinda curious.

Agreed on practicing maximal braking. If you get to the point that the rear wheel lifts AND you don't skid the front wheel or go over the handlebars, you can do no more. If you crash because you did skid the front wheel or went over the handlebars, then that pain you are feeling is irony, where you injure yourself developing skills that you need to prevent injuries. Swerving is also a valuable skill.

Just know that the act of braking transfers weight and traction to the front wheel, up to 100%, so that the front brake is very, very important to reduce stopping distance. Transfer your weight to the rear as you brake so that you can use that wheel to brake when it is on the ground, and so that you won't go over the bars if it isn't on the ground.

The bike takes longer to stop when skidding. If you keep the wheel or wheels on the ground rolling, and progressively squeeze the brakes to the point just short of a skid, you will stop in a shorter distance.

You want to avoid locking the front wheel as doing so makes the bike stop steering. Small steering corrections are how you keep the bike upright, and locking the front wheel can make you fall down hard.

Best bet will be to shift your body rearward as much as possible to avoid pivoting over the bars and then squeeze both grips. The rear wheel almost always will lock on hard braking as it is unloaded. When I stop very hard my rear wheel typically leaves the ground.

Btw, I do know how to brake, that question halfway down was satifying my curiosity. I was more wondering what you guys actually ened up doing when you get to a point where you either stop fast or die.

Obviously mine wasn't quite a perfect as it could have been, but it worked, slightly worrying trying control the bike with a locked front wheel but not too bad.

First I try to avoid the object while applying breaks, if I can't and I'm about to hit, I apply the back break a tiny bit harder than the front (so I can still steer), I lift my backside off the saddle and position myself behind the seat (like mountain bikers do when going down a steep hill), to try to slow down the bike with my body weight and to also not be propelled, head first, over the handlebars of the bike.

If I cannot stop in time, I prepare to release the handlebars, jump off the BACK of the bike and land on my feet or butt. I'd rather my bike hit the object WITHOUT me on it than to either be forced head-first over the bars or crash into the object while on the bike.

I had a near-ditch situation once but I held onto the handlebars while landing on my feet, behind my bike. with the front wheel of the bike lifting up (my bike was completely vertical at that point). It saved me from having to hit a crazy ped that ran out into the bike lane between a large SUV and a delivery truck. The ped didn't even look. Ugh.

You should practice emergency stops in a safe place with a helmet (and any other protection like elbow, wrist and/or knee guards). A little practice could save your life.

if you load up your rear rack with at least 10lbs of stuff in it, you can really jam on the front brake without having to worry about going over the bars :p

In a turn I will start off as far to the inside as safety allows. If I am going too fast while leaned over and am in danger of running off the road / hitting something and getting injured, I will stand the bike up straight, brake maximally for as long as I can, then lean the bike back over to avoid running off the road / hitting something. Using the brakes while leaned over is questionable, you need the tire traction for staying leaned over - lock up any wheel while leaned over and it will slide out from under you faster than you are going to correct for it. Leaning over more is an option at times, but when you get to the point that you can't or won't lean over more, do the above.

If I am going straight, the bike is upright, I grab the front and rear brake equally at first while I transfer weight to the rear, then start squeezing the front brake harder and harder until I stop or run out of room. If the front wheel skids let go immediately, if the rear wheel skids you can modulate or just keep it locked up, a rear wheel skidding isn't necessarily going to make you crash. In a panic situation I might let off the rear brake a tiny bit as the front takes over, I am not sure. I haven't locked up the rear wheel in a long time, I have raised the rear wheel off the ground on occassion, so I presume I might be modulating the rear to adjust for lower traction as weight is transferred to the front wheel.

There isn't any thought involved in any of this. Through practice and years of riding two wheeled vehicles, its somewhat automatic.

I think it's fair to say that in an emergency, you will react as you've trained -- whether it's a medical emergency, a self-defense situation, or things going random in traffic. There's some excellent technique advice in this thread, and I plan to do some practicing before I need it for real.

The BSS is a valuable skill for separating the girls who love Britney Spears from those who dig Buster Keaton.

both wheels?!?! WoW, can I have YOUR breaks?
I always test my breaks a bit so i know what i am in for when i need them.

In emergency stopping situations, only the front brake matters. If you are using your front brake to maximum efficiency, there won't be enough weight on the rear wheel to make any difference anyway.

You should practice in a parking lot or something until you can judge how much to pull your front brake so you're stopping as fast as possible without flipping over the front wheel.

Also, you'll get more stopping power if you can shift your weight back. If you have the reach for it and practice it, you can even drop your butt off the back of the seat and drop your weight way down. I wouldn't suggest trying that until you're pretty good at modulating your brakes though.

I understand the logic behind this statement, but think that cyclists are better served to use both brakes. First, there is a period of time for the weight and traction to be transferred to the front wheel. During this period of time, the rear wheel is rolling and in contact with the road, available for braking. Why ignore it? it might be 40% of your braking power very early on? Secondly, lets say you are going 25 mph and need to stop quickly. Do you really think you can do a "stoppie" from 25 mph down to zero? I know I can't. The best I can do is get the rear wheel off the ground for the last few feet. Up unitl the end, that last bit where I finally get the wieght and traction all the way onto the front wheel, that rear wheel is helping me stop.

But I whole heartedly agree that if you are going to use only one wheel, it should be the front. And if you can ride one wheel all the way to being stopped, then I guess you know what you are doing, and are just worlds better at it than me.

Here we go again:bang::bang::bang:

Both brakes matter in maximum stopping efforts. The front brake does the bulk of the braking work but the rear brake is still offering a not insignificant fraction...10%... of the overall braking ability of the bike. If you are braking so hard that the rear wheel isn't involved in the equation, you passed the limit of maximum braking power. Ask any mountain biker and they will tell you the same thing - once the rear wheel starts to skid, release pressure on the front brake. This puts the rear wheel back in contact with the ground and increases the overall braking ability of the system.

You can also increase the deceleration capability of the bicycle system by moving your center of gravity down and back as you brake the bike. This does not increase the front wheel's ability to brake but increases the rear wheel's ability to slow the bike. A tandem, for example, with it's longer wheelbase and greater weight over the rear wheel will decelerate a bike at 0.8 g vs 0.5g for a single rider bike. Moving back and down while braking makes your single bike more like a tandem.

If you want to learn how to brake, Dheorl, get a mountain bike and go use it like it was intended...off-road. The kinds of riding conditions that you find will much worse than any conditions you'll find on pavement. Learn how to brake on mud, loose dirt, roots, rocks, gravel, etc. and you'll never need to worry about panic stops on the road.

Hey cyccommute -

got any references for those braking pie quotes? I only have Motorcycle Safety Foundation info, and it sounds remarkably similar. I was reluctant to offer it up because the speeds, mass, braking power, and tires of motorcycles are so different, I figured there could be significant differences.

But your assertion that someone stopping a bike 90/10 front rear is a shorter distance than someone who gets to 100/0 has drawn my attention. I know that 90/10 works real well for myself, because the handling of the bike is very predictable when you keep both wheels on the ground, and that makes me more likely to keep progressively squeezing harder and harder.

Live eat and breath cycling. Dream about cycling. Become one with your cycle grasshopper and your questions will be answered.

I think it's possible that off-road braking is significantly different than road braking. In off-road braking, you could easily exceed the traction of the front wheel and cause it to start skidding; at that point you've certainly lost your most effective braking; sliding friction is a fraction of static friction. With a loose surface, you absolutely want to use both brakes and de-emphasize the front brake, because you need square inches on the ground to provide traction to brake with.

The same would be true on any surface where the front wheel's traction was not sufficient when braking to lift the rear wheel from the ground; gravel roads, wet pavement, snow, ice, etc. In fact, on ice and loose gravel or sand, it can be very dangerous to use the front brake at all. However, once you get to the point where you've got so much traction on the front wheel that you can flip the bike over it, I don't really get how the physics could support anything but maximum braking on the front wheel, just to the point where there's hardly any contact on the rear wheel. If I'm braking 90% front, and 10% rear, and I increase the front braking power a bit so it's 100%/0%, and I still have not started skidding the front tire, I don't believe that I'm slowing down SLOWER than I was before I increased the braking power on the front.

It certainly is not a good idea to go all the way 100%/0% in almost any situation though, since you'd have almost no control left. But if I'm anywhere near that, I'm going to let go my rear brake, because the rear wheel would skid with almost any brake pressure when that much weight had shifted forwards, and I do NOT want either of my wheels skidding in emergency situations; skidding = loss of control and much less traction.

I am not insisting that I'm right, but I can't visualize how the physics would support the partial-rear-brake balance as stopping faster. I'd like to see the study, or if someone wants to draw up the force vectors of the two situations, I'd be very interested.

Applying some pressure on the rear brake can also help maintain control of the bike if you are swerving sharply while braking. Although that seems pretty instinctual.

I would offer only statistics - as in only a fraction of the time will 100/0 braking be achieved, and an even smaller fraction where it is done safely and correctly. However, 80/20 or even 90/10 can be achieved a lot easier, repeatably, and with confidence. Therefore, training riders in keeping both wheels on the ground using mostly front braking will cause better results and shorter stopping distances as a whole.

This would not benefit those riders who are at the very edge of the bell curve who can brake and handle a lot better than most - just like the motorcycle racers demonstrate when they lift the rear wheel slowing down at speeds over a hundred miles an hour. However, asking your average middle aged Harley rider to practice a stoppie would keep the emergency rooms full all summer. The MSF (Motorcycle Safety Foundation) taught that motorcyclists were widely afraid to use the front brake. Just getting the average rider to go to 60/40 or 70/30 made them incredibly more safe than relying on the rear brake primarily. My Honda goldwing is so large (900 + pounds) that the rear brake can not be activated independently - hit the rear brake and one front brake gets squeezed as well, maximal braking requires both front and rear simultaneously by design. I have yet to see any data or references for bicycle riders, and have no idea how many apply what brake and to what extent, nor how the lighter bicycle/rider system and slower speeds affects things.

I think that the difference between 90/10 and 100/0 might not be all that large anyway, so having either skill would be considered darn good braking.

Interesting about the interlock on the Gold Wing. Do they make a point of telling you that when you buy one? (Just wondering.)

i agree with others practice and use the front brake. if possible get a buddy and an empty parking log. have them bump into you at slow speeds and higher speeds. practice making bank turns, hairpin turns, picking up water bottles and being able to bunny hop them.

in the last month i've had to make alteast 3 emergency stops. just yesterday a car almost right hooked me merging into the bike lane just 4 feet infront of me when i was going 17mph into a business parking lot. i applied my front brake and rang my bell served into part of the right lane, then shouted cause they didn't seem to notice. it wasn't a textbook emerceny monover, but i felt i did an ok job. if you want to get better practice and ride more.

and yes the front brake has twice the stoping power as the rear brake. i almost never use my rear one