SafetyBits: Braking

Make To Make Yourself a Safer Rider, Part Three

By Mark Yeager

There are a lot of misconceptions about a motorcycle's brakes: Many riders think that they know how to brake, yet they have not even scratched the surface of the braking capability of their motorcycle.

THEM'S THE BRAKES

Like many other techniques in the motorcycle world, effective braking takes some understanding of the mechanics involved. There are two types of motorcycle brakes -- the first is a drum brake and the second a disc brake. Naturally, there are advantages and disadvantages to both types; 
BRAKE
                PRO                             CON

DRUM            Sealed against water/dust       Poor heat dissipation
                Predictable at low speeds       Low power at high speed

DISC            Good heat dissipation           Open to dust/water/debris
                'Grabby' at low speed           Smooth and powerful at high speeds
If you took a look at part one of this series (Slow Speed Riding), you noticed that I advised that you not use the front brake during low (walking speed) maneuvers. This is especially true if your bike has a disc front brake, because the brake has a tendency to grab or stop suddenly at very low speeds, therefore upsetting your balance and causing (aargh!) a dab (foot down).

Your bike will most likely have discs front and rear, or a disc front/drum rear. Older and smaller bikes will have drums at both ends. Most manufacturers have gone to what is known as a "triple disc" setup (dual disc on the front, single disc on the rear). On modern bikes (past 1980 or so), front brakes are always designed to be stronger than the rear. If that makes you nervous, read on and find out why they're made that way...

POWER OF A DIFFERENT SORT

The front brake is probably the most debated control of a motorcycle. If any of you out there don't use your front brake, this column will change your riding forever. The techniques I am about to talk about are for normal riding procedures -- you know, around town, cruising down the highway, that sort of riding. (If you want to see how to use the brakes in ultra-low-speed maneuvers, see article 1 of this series.)

It is true that the front brake provides 70 to 100 percent of the stopping power of a motorcycle. To explain this wonderful phenomenon, let's go back to physics class: We have all looked at sportbikes in the recent years. The back tire is wider than most small cars' while the front tire stays relatively narrow. Why? When you are accelerating (in a straight line for the sake of clarity), the bike's weight -- which is normally biased toward the front, offering it more traction than the rear -- transfers to the back of the bike. If you have too small a tire 'footprint', the power will overcome the available traction and the back wheel will spin. If you doubt this, take a look at a motorcycle drag race. The front wheel doesn't touch down for 1/8th of a mile. This is affectionately known as a wheelie. The same principle applies when you are braking (though in reverse). As you apply the brakes (front or rear), the weight of the bike and rider transfers forward and eventually onto the front wheel. This is why a bike's front end dives when you brake. The amount of weight transfer depends on the weight of the bike and it's load, as well as the amount of braking power applied to the bike. The harder you brake, the more suddenly the weight transfers forward. However, all that weight must come from somewhere. It comes from, you guessed it, the bike. While the front wheel and suspension are busy doing their stuff, the back wheel quietly gets lighter and lighter. Now we find out why front brakes are so important. All that weight is transferring to the front wheel and off the back, so we have more traction on the front, and therefore, more braking power. And at the same time, less traction and potential braking power on the back wheel. With a good sport bike, it is possible to get 100% of the bike's weight on the front wheel so that the back wheel lifts right off the ground as the bike stops. This kind of reverse wheelie is generally only accomplished by skilled riders on a closed track. Trying this on the street can have serious repercussions if you goof it up! This trick is known as an "endo" or "stoppie."

LOCK IT AND LOSE IT

Braking in normal situations is fairly straightforward. Unless you are on deep gravel or some other really slippery stuff, use both brakes when stopping or slowing. When my right fingers go to the front brake lever, my foot automatically goes onto the rear brake. Practice using more front brake than rear. If you are stopping your bike primarily with the back brake, you are missing the point. The front brake holds the primary stopping power. Use the back brake as kind of an accessory. One nice thing about the rear brake is that it provides some degree of stability when braking. The key here is a balance between front and rear, with about 70% of the emphasis on the front. Brakes are not a sudden thing. Both brakes must be applied smoothly. That doesn't mean slowly, just don't go grabbing your front brake or jabbing your rear brake -- you lock a wheel and could spit yourself off. By squeezing the lever, it gives your brain time to judge the amount of input you are giving your bike, and what the bike is telling you about that input. Grabbing the brake is equivalent to having a switch that controlled our brakes rather than a lever. Imagine your brakes fully off or fully on with no in-between. What a nightmare! That's what it's like if you grab your brake. So you must be smooth.

By the way, almost of the power in your fingers is in the first two. There is very little power in your 3rd and 4th (little) fingers. So, use all 4 fingers when you brake -- this is a matter of preference with most riders, but it's my opinion that new riders should use all four. As you become more experienced, try using the first two fingers -- once you're good at it, this can offer you slightly more control of the motorcycle since you've still got two finger wrapped around the bar to make steering inputs.

At any rate, if you have been around motorcycles for any length of time, you have undoubtedly heard someone say that you shouldn't use the front brake because it'll lock with little provocation and you'll be horizontal in a hurry. Brake lockup is, in case you had any doubts, a bad thing. We can live with the rear wheel locked for a while, but lock the front and you'll be down. The front is one of those dump-now-and-ask-questions-later brakes. I have seen some front brake lockups recovered, but only by top-notch riders on excellent bikes in a controlled environment. Even then, the lockup was only long enough to get a chirp from the tire then he recovered. If you do find yourself in a stressful situation where you've locked up either wheel, don't panic! You can recover if 1) You're lucky and 2) When you do let off the brakes, ease them out -- don't do anything sudden, but you do want to get the wheel(s) unlocked as quickly as possible -- and make sure everything's pointed straight when you ease off the brakes. This is what causes so many crashes: People panic, lock up the brakes and either lowside, or they totally let go of the brakes and bike "hooks up" and straightens itself out and flicks the rider off. Again, make sure that the bike is straight up and that both wheels are pointed forward and you've a (admittedly slight unless you're a really good roadracer) good change to save it. Another point about locked wheels: If you lock the rear wheel and it starts to "come around" on you, ease off the rear brake and it'll come "back in."

YOU DESERVE A BRAKE TODAY

Okay now I have you thoroughly confused. Use the brake, don't use that brake. Use the front brake, don't abuse it. Generally, the front tire will take quite a lot of abuse before it locks up, and it'll warn you before it does. Each bike is different, so it's important to practice this on your own bike. Maximum braking occurs just before the wheel locks (how nice). This is called 'threshold braking'. When we teach emergency braking, we can tell when a student has mastered threshold braking because the tire will leave a very light 'gray' (skid) mark. If it's black, they've locked it. So, the object of the game is to get the wheel as close to lock as possible without actually locking it. Boy, what fun. If the rear wheel locks up, the bike will lose a bit of it's stopping power because of the lack of traction, but more importantly, the back wheel will tend to drift from side to side. If you are braking in a straight line when this happens, it's not a big deal (feels a little exciting at times, though). However if you're in a corner when this happens, prepare to pay for some plastic. Again, if the rear wheel locks, release the rear brake slowly and smoothly. If you just pop off the brake and your wheel is at all drifting to the side, the wheel will catch the road suddenly and you'll highside the bike. Not very likely but it can happen.

Okay, that covered the easy one, now onto the front brake. A number of things happen when you start to apply the front brake. First, the shocks will compress as the bike does that weight-transfer thing. This, thank goodness, puts weight and extra traction on the front wheel. At this point, you are doing normal braking. If you continue to squeeze the brake lever, the front brake will get more and more weight on it. Eventually, most of the bike's weight will be on the front wheel. At this point, you are fairly close to threshold braking. If you continue to squeeze, and front wheel will start to complain. This is where you must be familiar with how your bike gives you input. We've found that on most bikes as you approach lockup, the front wheel will start to squirm. The rider get a vibrating or light shaking sensation through the handlebars -- it's not a violent motion, rather, it is quite subtle. If you feel this, you are at maximum braking. Do not squeeze the lever any more or you'll be rubber side up! This sensation is caused by the tire locking for fractions of a second then rotating again, and the squirming is the tire sliding just a fraction of an inch or so, then regaining it's grip, then sliding again. If it didn't regain it's grip, it'd go into full lock and, well, you can fill in the blanks. You can now see how close to lockup perfect braking is.

WE HAVE THE TECHNOLOGY....ABS

I have to be really honest here. I've never ridden a bike with ABS. I have, however, practiced techniques with our local police department. We do some of their training and they let us observe and ride with them when they do the fun stuff. They ride BMW K100RT Police bikes with ABS. We were practicing high-speed emergency braking in the rain once, and the minimum speed to reach before braking was 80Km/H (about 50mph). The ABS bikes were doing pretty well, but we were consistently out braking them on our personal non-ABS bikes. ABS is not the end-all be-all of brakes. I think they are one of the biggest advancements in motorcycling in the last 10 years, but in the same breath, though, they are not meant to replace rider skill. ABS is designed to sense traction problems and react faster than a rider can. If you are threshold braking in a straight line and run over a patch of gravel (or water/oil, etc.), the front wheel will probably lock because of the sudden loss of traction. You just cannot sense (unless you see it coming and back off the brake) that loss and react quickly enough. This is where ABS really shines...in the real world. Sure, we were outbraking ABS bikes in a controlled environment, but had there been a patch of oil on our braking path, we non-ABSers might have been toast. ABS is a wonderful invention that has and will save many lives. As with most other things, it is great at what it is designed for but don't count on it to fill in the gaps where your skill level sags. It should compliment your skills, not replace them.

I've ridden ABS-equipped bikes and found that I can stop faster with the ABS disabled. But that's only from all the track time we get playing with new bikes and roadracing -- so if you don't race and can afford the extra two grand ABS tacks onto the price of a new bike, get it. You won't be disappointed. --Brent Plummer, Editor

Again, please don't be afraid of the front brake. I have been riding for quite a while, and have talked to literally thousands of riders of all sorts over the years. I can probably count on one hand the number of first-hand accounts of a front brake lock up that I have heard. Treat your front brake like a powerful engine; once you get used to it you're not afraid of it, but bite it and it'll bite back. Brakes are your friend, and if you practice these techniques they will save your life at least once in your motorcycle career.