Tuesday, October 21, 2008

Bodies in braking.

"Why do I always stomp down so hard on the rear brake when I'm stopping quickly?"

This was a question asked of me by a student in an advanced course. The Road Warrior part of me wanted to make some sort of flippant reply. Like this:

"Because you're a dumbass! If you know you're doing it, just don't do it anymore!"

Which would have been great for my ego but wouldn't have been of much use to the student. This student was sincere in their request for information. This person had obviously tried to quit using so much rear brake. Despite that, it kept happening. I needed to give them some meaningful feedback that would actually help correct the problem. Which I was able to do, of course. Come on, I'm the Guru, right?

In order to fully understand how things work we need to look beyond the physical. You may have heard of an athlete of whom it's said they have good mechanics but still aren't great. The key to greatness is realizing that there's both physics and physiology involved. In other words, we need to become aware of how our body reacts to certain situations. Once we've achieved that awareness, we can make our bodies work for us instead of against us. Like I've said before, successful riding is comprised of unnatural acts.

My first real exposure to delving into the big picture was provided by a past instructor. It was during firearms training in Academy. As we were being schooled in proper techniques the instructor told us to watch each other as we were shooting. We were told to look at the dynamics of the human body while drawing and firing a weapon. It was a lesson in both the mechanics and physiology of shooting. This would prove valuable in later years. Whatever your view of firearms, the same principle applies to riding a motorcycle.

With that in mind, let's go back and see how this applies to a better understanding of what's happening during maximum braking. Maybe we can take our skills to a little higher level in the process.

First off, let's look at the mechanics of braking.

We all know about weight transfer, right? As we begin braking the weight of the bike and rider moves forward. This weight gives us more traction for braking. It's not there all at once, so our squeeze of the brake lever has to be progressive and smooth. As the front of the bike weights, the rear gets lighter. Less weight means less traction for braking. In other words, we squeeze more firmly on the front lever while using light to lighter pressure on the rear brake pedal. Since the weight eventually quits moving forward and starts to equalize again, we also need to let off the front brake a little right at the end of the stop. Pretty standard stuff.

Another mechanical aspect is the position of the foot peg in relationship to the brake lever. For this particular student, the peg was close to the pedal. The student also had rather large feet. When the student applied the rear brake a large part of his boot was pressing on the pedal. This resulted in quite a bit of pressure initially, as well as a lessened ability to lift his boot for lighter pressure. The student needed to move his foot back on the peg. Actually, moving the peg permanently would be wise if possible.

Now let's look at the physiology involved. Just to avoid a separate issue, I'm going to throw in one other "p" word here. That's the word "psychology". Not that we're psycho for riding, although some unenlightened individuals might call us that. What I'm talking about is how our perceptions are altered by the physical size of the rear brake pedal.

I don't know if you've ever taken a close look, but a lot of cruisers have really large rear brake pedals. They're almost the size of the brake pedal in a small truck. This situation can create a psychological impression that there should be a lot of braking available from a pedal that size. It's just not true and a rider needs to ignore the mental picture created. Good technique is always "light to lighter" on the rear brake no matter the size of the pedal!

A definite physiological aspect to braking is where we look while stopping. I wrote a post about this a long time ago. Not only does keeping our eyes up and looking well ahead provide stability and help us stop in a straight line, it also affects how we apply the brakes. Simply put, looking down makes our bodies clench more while looking up opens up our stance and smooths things out. Try it sometime in a safe place. Notice the difference in smoothness when looking well ahead as opposed to looking down at the instruments or a few feet in front of the bike. Why not work with our body's natural reactions?

Speaking of natural reactions, consider this. Maximum braking on a motorcycle is stressful. Whether on the streets or just in front of an instructor, heart rates go up and adrenaline flows. Somewhere in the back of our minds is the thought that we're trying to avoid either hitting something or having the bike fall down due to a front wheel skid. In either case, the word "impact" is floating around in our heads. It might not be that exact word, but our body anticipates the hit. So what does the body do?

Think about the last time you rode in a vehicle with someone else and had a close call. It might have been a friend or partner who wasn't paying close attention to what was ahead. Perhaps it was teaching a young person to drive. Anyway, what did you find your physical reaction was? Didn't you brace yourself some way? Either with your hands on the dash or with your feet on the floorboards? Maybe both? Even if you were the driver and pushed the brake pedal, what was your left foot doing? Bracing your body, wasn't it? Both feet were pressing hard on something.

So what makes stopping a motorcycle any different? Our feet are called into play by the physiological reaction to the situation. The feet and legs want to brace us against the conjured up impact scenario. What just happens to be under the right foot? Riders often find themselves applying way too much pressure on the rear brake as a result. Most of the time they're not even aware of it. Such was also the case with my student.

The answer is simply to get in the habit of bracing our knees against the gas tank. This way the body can still clench and brace but the force is applied higher up. Without all the pressure on our feet we can use the proper pressure on the rear brake. The added benefit of pressing our knees against the tank is that it keeps the posterior firmly planted in the seat. That's a much better control position. With some ABS bikes, I've seen riders come quite a ways up off the seat. Better to stay seated.

Bear in mind that the correct actions aren't going to come automatically at the time they're needed. You knew this was coming, didn't you? The only way to make sure we do exactly the right thing in an emergency is to practice. Practice doing it right over and over. Notice I said practice doing it right. Practice by itself doesn't make perfect. Perfect practice is what makes perfect. Sorry, there's no other way. Repeated perfect practice teaches the brain and body to work together in harmony. Both mind and muscle will know how to apply exactly the right braking pressure in an emergency.

What? Are you still reading? You should be out riding and practicing! Get out of here!

Miles and smiles,

Dan


6 comments:

Richard Machida said...

Great analysis. I really enjoy these type of posts. Unfortunately, all of the snow prohibits any practice. Next spring, it will be like starting all over again.

Bryce said...

""What? Are you still reading? You should be out riding and practicing! Get out of here!""

Are you nuts? We had snow, heavy snow
within a half hour drive of here on Monday and Tuesday. And in many places the local to the area roads and streets are now covered with a thick layer of salt.

Riding season is over!

And locally the temperature today is well below freezing, very windy, yet the sun is out. go figure.

As to the braking...

Goldwings produced after my 1981 model has the linked braking.

And guess it is OK, however I prefer to control the braking systems. My ten year old Honda car
doesn't have ABS, something else to go wrong IMO.

I suspect down the road we all will have airbags, linked braking, ABS,
and speed controllers on our motorcycles. And motorcycle riding will be limited to those 60 years and less, over sixty you get a wheelchair, with an electric motor!

-Tim said...

Interesting write up...I never really thought of it that way. As I think of my braking habits on a daily basis, not just emergency braking, I realize that I barely touch the rear brake at all...hmm...
anyway...looking forward to being back in the good old PNWet...hope to get into an advanced course when I am back, since getting one here is next to impossible because they just don't happen...

The Snark said...

What's a rear brake pedal? I've never used one before. :-P

Steve L. said...

I developed a bad braking habit when I first learned to ride. I found that I started using only two fingers on the brake lever when riding around town and coming to controlled stops in regular traffic.
When it came to needing maximum braking force, my habit was to grab the lever with just two fingers, and as a result, I didn't have maximum braking force!
Luckily I came across this realization when I was practicing in a parking lot and quickly changed my braking habit and relearned a new one.

Practice, practice, practice. That's what creates habits and habit is what happens in an emergency.

People on motorcycle forum I frequent asked me why I bother with the downshifting while emergency braking. They think it takes away concentration that is needed for maximum braking.
I told them that if you practice downshifting to 1st while emergency braking, you don't have to even think about it - it's automatic.
The biggest concern after coming to a rapid stop is that the vehicle behind you hasn't!
Typically from a higher speed emergency stop (faster than those practiced on the courses) you have all the time in the world to downshift, as it takes surprisingly long to come to a complete stop from freeway speeds.

Antoher thought I had on why it's natural for most people to put too much pressure on the rear brake is that most people drive cars more than they ride bikes. How do you stop a car? Stomp on the brakes!

irondad said...

Richard,
Thanks for the positive feedback. I sometimes wonder if folks care about these kind of things or just want to be entertained.

Bryce,
I've been called "nuts" before. Although not by anybody as tall as you! Snow? All the more reason to practice good braking skills, right?

Tim,
For the most part the front brake provides enough stopping power. There are a couple of considerations, though. Using the rear brake helps keep the suspension set correctly. The biggest reason for always using both brakes is because that's the most effective way to stop.

When we find ourselves in a high adrenaline situation, like when every orifice in our body wants to pucker, we fall back on habit. The goal is to make our habit the one that works most effectively for us.

I was wondering how far off you are from moving. You discontinued the countdown on your blog!

Snark,
I've seen you carve corners. It's quite possible that your bikes no longer have rear brake pedals. Remember those spark showers? That was the pedal grinding off!

Steve L,
You totally get it when you say habit is what happens in an emergency. Note my comment to Tim.

Some bikes will allow for maximum pressure with two fingers. Trouble is, most riders won't stay with two fingers in a real emergency. The human grasp reflex makes us reach out with all four fingers. That's a variable that we don't need right at that time. Better to have developed the muscle memory ahead of time for modulating the front brake lever with four fingers.

Another good reason for downshifting while braking is that not all braking results in a complete stop. Something may happen where a rider needs to get off the brakes and make an evasive move like swerving. The gear selection should be keeping up with the bike's speed.

Take care,

Dan