Monday, November 4, 2013

Braking Technique and Going "Over the Handlebars"

A couple of months ago Jan Heine posted an article on his blog about effective braking technique on a bicycle. In the post Jan talked about tests that Bicycle Quarterly had performed to learn some things about braking performance. The tests explored both the equipment (brakes, shoes and pads) and braking technique (front only vs. rear only vs. both), but in the blog post Jan talks about conclusions related specifically to braking technique.

One of the conclusions that seemed quite counter-intuitive to me is that on dry pavement, the front brake alone will stop a bike faster than both the front and rear brakes applied together. It’s easy to understand that under hard braking, the rider’s center of gravity shifts forward, significantly unweighting the rear wheel. As a result, the rear wheel has little traction and can’t help much with braking. But why would using the rear brake actually diminish braking performance? The article doesn't completely answer that question, but I get the impression that it has more to do with human psychology and physiology than with physics. That is, when we brake with just one lever, perhaps we’re better able to focus our effort on stopping the bike safely and quickly.

Jan was convincing enough in the article to get me to consciously shift my behavior from using both brakes most of the time to almost exclusively using the front brake. I still use the rear brake in certain situations, like when signaling with my left hand, braking on slipper surfaces or controlling my speed on a long descent, but otherwise I've been almost exclusively using the front brake lately.

Using the front brake alone is a bit unsettling at first for some who don’t have a lot of cycling experience. It’s easy to imagine braking too hard with the front brake and something like this happening:

But as Jan points out, it’s possible to brake quite hard with the front brake without going over the handlebars as long as you shift your weight backward and brace yourself firmly against the handlebars so that the deceleration doesn't force your weight forward.

Recently I did some real world testing of my own on this whole over-the-handlebars issue. My methods may have not been up to the same standards as BQ, but I think I came away a little smarter none-the-less.

I was coming home from work on the Burke Gilman trail, riding my single speed Trek 311 which lately has been set up with a fixed gear drivetrain. I'll admit I was going faster than I should have been as I approached an intersection between the trail and a road that generally sees very little traffic (actually, I was going about as fast as I could, trying to squeeze in some interval training on my commute home). At this particular intersection, it's very difficult to see a car coming until you're almost into the intersection. I was leaning forward, stretching my neck out trying to see around that corner a fraction of a second earlier so I wouldn't have to lose any momentum. Unfortunately what I saw just as I entered the intersection was a car on a perfect T-bone collision course with me. There was no time to thoughtfully reflect on the BQ brake tests or to consider which brake lever would stop me quickest. It was complete instinct and muscle memory that grabbed the front brake as hard as it could.

Okay, let's pause to review some of the facts we've learned so far:
  • I was going pretty fast. Definitely over 20 mph.
  • I was leaning forward on the bike, trying to "see around the corner." (yeah, like that's really going to help)
  • I was riding a fixed gear bike.
So here's a thing about fixed gear bikes. I've spent a fair amount of time riding fixed gear bikes, but I still occasionally "forget" that you can't stop pedaling on one. Generally when that happens it's a very momentary thing; the bike quickly reminds you with a strong "nudge" and you're back to pedaling, no harm, no foul. Of course that friendly nudge reminder tends to push you forward on the bike since as soon as you stop pedaling, the cranks want to take your whole body in a circular trip with them over the front of the bike.

Back to my story. So as you can imagine, the same instinct and muscle memory that caused me to grab the front brake with all my might also told my feet, "STOP PEDALING NOW!"

You can see where this is going, can't you?

In what seemed like a nanosecond I felt the back wheel of the bike lift up as I went somersaulting over the handlebars and landed on my head and right shoulder on the pavement directly in front of the car. All I remember about the impact is the deafening crunch of my helmet and body striking the pavement. There was none of the super cool time-freeze effect that Joseph Gordon Levitt's character experiences in Premium Rush. No weighing of options, no super slo-mo flight through the air. Just a loud crunch.

With my right clavicle in four pieces, four sprained fingers, and a number of other bumps, scrapes and bruises, I dragged myself and my bike out of the middle of the road and sat down next to the trail to take inventory. I knew immediately my collarbone was broken. I've broken a couple of bones before and there's a certain unmistakable feeling when your bones aren't all where they belong.

I never lost consciousness, but between being in shock and most likely having suffered a mild concussion, my memories of the first few minutes after the crash are fuzzy. I know the driver of the car got out and asked if I was okay, but I have no memory of whether they were male, female, young, old or what kind of car they were driving. I apparently convinced them I was okay, because they left me sitting by the trail trying to work out my next move. The next move of course was to call Sarah and ask sheepishly, "can you come get me and take me to a hospital?"

Okay, so what did I learn from this experience? I'm still trying to figure that out, but here are few things that come to mind:
  • Sometimes I can really be an idiot.
  • It takes about 12 weeks for a fractured clavicle to heal completely and during that time you get to see some really breathtaking bruises.
  • It's difficult to shift your weight back quickly on a fixed gear bike.
  • When your head hits the pavement, a helmet is a good thing to be wearing.
  • Leaning forward to peek into the intersection as you approach is not the same as slowing down.
  • Blowing through an intersection at high speed just because there "usually" aren't any cars there is a bad idea.
As far as braking technique, and going "over the handlebars," I'll continue to do most of my braking with my front brake. I have little doubt that it's possible to stop very quickly and safely on a bike using only the front brake, if you have time to prepare. Had I grabbed only the rear brake in the scenario described above, I would have barely slowed down as I skidded into the intersection directly into the path of the car. Luckily the car stopped in time, but if they hadn't, the rear brake would have been no help.

The key is having that time to prepare. So, if I learned nothing else from this experience, hopefully I at least learned to pay attention and always be prepared to stop when approaching uncontrolled intersections. In other words don't act like I'm Joseph Gordon Levitt in Premium Rush because, duh... that's not real.


  1. Oh my, that's terrible. Glad it wasn't worse though. 12 weeks.. how long before you will be riding again you think?

    1. The accident was 3 1/2 weeks ago and yesterday was my first day riding to work. But today my shoulder is very sore and I'm deciding that was too early to start riding again, so I'm going to give it more time. Maybe in another week or two?

  2. Sheesh, horrible. Glad it wasn't worse. Heal up quick. Cheers.

  3. Damn Steve, sounds spectacular! Hope you're well onto recovery by now.

  4. I just came across your blog and am really enjoying it. (I also left a comment following the Trek 560/760 post.) Very sorry to hear about your accident and broken clavicle. Broke one myself falling off a bike when I was 18 years old. I remember the doctor saying the break would heal just fine, it would be the joints at either end that may not be so good. How right he was. Starting in my 30s, and continuing until now, in my late 60s, the joint at the sternum has bothered me, especially after a long day. Some, but less trouble at the shoulder end. Hope your recover is complete. Don't push it too hard, although I am sure you are eager to get back on the bike. -Paul

  5. Nice read! I like the suggestions.

  6. Last weekend I was riding my Dahon TR Speed-(a collapsible) bike home and took a steep descent down 8th street in Atlanta. I can't remember why I had to break (perhaps the concussion I suffered) but I did quickly and I'm not sure which break I hit first, but used both. I flew over my handle bears right on my chin then lip. My palms had skin scraped off them so I might have broken my fall with them first. My knee was also skinned. I saw stars and after assessing that my teeth were still intact, and my neck wasn't broken I picked myself up and walked home seeing a white haze the whole time as my vision was very blurry. It all happened so fast and not remembering how I ended up on the ground or why is the scariest part. I'm glad you are doing well and thank you for your post. It's good to know there are others willing to share tales.

  7. Sorry to read about this accident :(.

    As far as physics goes, one reason that the front brake is faster than both brakes is that if you're using both, you will (1) cause the rear wheel to skid; (2) the skidding rear wheel combined with the stopping force from the front wheel causes fish-tailing.

    Having said that, there are lots of ways that panic-stopping with the front brake can go wrong. The crash you experienced was one; I've had a related problem where instead of going over the handlebars, I've instinctively backed off the front brake to avoid tipping forward, but have found myself stopping only centimeters from a fast moving car as a result.

    My conclusion is that cyclists should practice not only using the front brake to stop, but shifting our weight back rapidly, so that we're ready for panic stops when we need them. It's too easy to stop with the front brake lazily, with weight forward due to putting a foot down (or for visibility, as you experienced).