The Motorcycle Back Brake Is There For A Reason. Use It!

For many riders, the back brake of their motorcycle is the anatomical equivalent to the appendix. They perform a very minor function overall and if they’re removed you wouldn’t be any worse off. Yet, your back brake is another arrow in your quiver when it comes to reducing your speed as rapidly as possible.

For many, the back brake is used only when travelling at low speed. Think parking your bike at the shopping center carpark or filtering slowly between traffic. Most riders are taught that the rear brake assists the motorcycle with low speed stability and if you remember your training or have been involved with motorcycle gymkhana, you’ll know this is true.

Unfortunately for a lot of riders this is where it ends. Carving through the canyons on a sportsbike – no need for a rear break you hear. Even when coming to an emergency stop in a straight line, there are a huge number of riders who don’t even consider using the rear brake and I have a theory why.

The premise of this theory is located at page 104 of A Twist of the Wrist II. Here’s the quote under the subheading Rear Brake:

The obvious mathematics of the situation are that the front wheel can do 100 percent of the braking and the back at that point just locks up no matter who you are.  Learn to totally rely on the front brake for quick, clean stopping; then, if you still have a use for the rear, go ahead and use it. But realize that the rear brake is the source of a huge number of crashes both on and off the track. I’ll leave the final decision up to you. While it is true for most riders that a motorcycle will come to a full stop quicker with both brakes applied, in racing, you don’t come to a full stop until you’re done.

Now, it’s reasonable to say that what Keith Code was focusing on here was the use of rear brakes at the track where the need of the rear brake is definitely lessened (although not eliminated). Some have taken this passage so close to heart they’ve turned up at track days with the rear brake system removed to save weight!

We would however argue that rear brake lock-ups are a result of poor technique rather than an inherent flaw in motorcycle design. You also have to remember that A Twist of the Wrist II was published over 20 years ago and not only has technology improved so that rear brake locks-ups are less common, they don’t even happen at all on an ABS equipped bike.

Unfortunately, many riders decided to transfer the above quote from the track to the road. They told their mates that you don’t need to use the rear brake on a sportsbike and the wrong information ended up being presented as fact.

The short of it is that using both your front and rear brakes together when coming to a complete stop will reduce your stopping distance. That’s why Honda, BMW Motorrad and other manufacturers offer some bikes (even sportsbike) with a combined braking system – a system whereby pulling the front brake lever activates both the front and rear brakes simultaneously.

We did a test to prove with numbers what the difference in stopping distances are between using only the rear brake, the front brake and both combined. This test was done at a speed of 80 kph, or 50 mph

Motorcycle Back Brakes Are There For A Reason. Use Them!

As you can see, by using both the front and rear brake, stopping distance reduces by around 4 meters or 13 feet. Put another way, a reduction in stopping distance from the front brake alone of over 23 percent. In an emergency situation that’s a fairly significant amount of distance reduced, especially when you consider that 4 meters is the length of a small/medium car.

Like just about every input in motorcycle riding, the key to good use of the back brake is:

  • Do it consistently
  • Do it smoothly

If you never use your back brake, come the moment when you’re hurtling towards a car that’s run a red light, there’s little chance your muscle memory will respond by moving your foot to actuate the rear brake lever. So be consistent – whenever slowing to a complete stop, always use the rear brake.

Smooth application in this instance applies both to the front and rear. If you’re not smooth on the rear brake you’ll lock the rear wheel (even on a bike equipped with ABS you want it to be smooth). Perhaps just as important is the smooth application of the front brakes, especially in higher end motorcycles with massive stopping power – the rear brake will do absolutely nothing to reduce stopping distances if you’ve lifted the rear wheel in the air which will happen if you’re too forceful on the front anchors.

So remember, motorcycle companies install rear brakes for a reason. Use them.

Motorcycle Back Brakes Are There For A Reason. Use Them!

 

ABS Motorcycles vs Non ABS Motorcycles – Do You Need Motorcycle ABS?

The ongoing ABS motorcycle vs non-ABS motorcycle is a strange thing. I would wager that it is impossible today to buy a new car in the western world without ABS. It’s a standard feature on the most high end of sports cars down to family sedans and small hatchbacks. It’s only not used in motor sports like Formula 1 because it took away from the required skills of the driver and made braking too easy. Despite all of this, there is still a large percentage of brand new motorcycles that either don’t have ABS at all or as an option. So if ABS on four wheels is good, why do some consider it on two wheels to be bad?

It’s especially baffling because braking on a motorcycle is much more difficult than for a car. First of all, you have separate controls for both the front and rear brakes on a bike with a requirement to apply differing amounts of force to each – one with the right hand and one with the right foot. On a car, if you lock the front brake it’s easy to release the brake pedal and reapply pressure. On a bike, a front wheel lock like will almost always result in a crash. Ironically, a study by the Association of European Motorcycle Manufacturers (2004) showed that many riders, fearing a front brake lock didn’t apply anywhere near maximum braking force which resulted in longer stopping distances and therefore avoidable accidents.

Bosch ABS

So is it necessary to have ABS on a motorcycle? Can a skillful rider brake faster on a bike without ABS then with it? We’ve combed through a variety of published journal articles as well as motorcycle magazine testing to find out just that. And we’re also going to refute some common claims around ABS that Joe Squid likes to trot out as to why he doesn’t have ABS on his bike.

Firstly a quick summary on how ABS works from BMW who were the pioneers of making ABS standard on motorcycles:

Wheel sensors measure the rotational speed of the front and rear wheels and identify when the wheel begins to lock. The sensors pass on a measured impulse to a processor, which activates a pressure modulator in the hydraulic brake circuit of the front or rear wheel. The activated pressure modulator reduces brake pressure in a fraction of a second and then increases it once more. This means that the ABS applies just the right amount of brake pressure within the ABS range to the appropriate wheel as required to keep the wheel just short of locking point.

Want to know how many times those wheel sensors measure for a wheel lock per second? On the latest ABS systems, it numbers in the hundreds of measurements per second.  And when it kicks in, brake pressure can be adjusted up to 10 times per second. A human being cannot replicate such performance.

But I’ve seen tests where a rider is able to brake faster without ABS than with ABS?

Yes, that’s very true but think about why. If a bike engages the ABS system, it’s because a situation is detected where the front wheel could otherwise lock. But ABS on a bike will only engage when needed, it’s not as if ABS engages when you casually slow at a traffic light. Older ABS systems on motorcycles (especially those that were pretty much a copy of car ABS systems) may engage too quickly and unnecessarily, but we’re a long way down the road from those today.

Therefore a bike with ABS will brake just as quickly as the same bike without ABS if the ABS isn’t activated. It is only when ABS is activated that it may result in longer braking distances and that is because the sensors are adjusting brake pressure on and off (or to put it better, more and less pressure is applied) to prevent a lock up.. If you were to lock a wheel when on a bike without ABS (and not crash), your stopping distance will also increase and will itself will be further than that of an ABS assisted stop. What you’ll find in the tests we go through further in is that ABS is intentionally engaged (in other words, a wheel lockup is induced) to measure the stopping distance, whereas for the non-ABS bikes, the rider is instructed to brake as best as possible without a lock up.

Just remember these two things:

An ABS equipped bike will stop just as quickly as a non-ABS bike if ABS isn’t engaged.

A non-ABS equipped bike will take longer to stop if a wheel locks than an ABS equipped bike when ABS is engaged.

Bosch ABS

I’ve locked my front wheel before and not crashed. It just takes good reflexes

Here’s a breakdown of how a human reacts to something:

  1. Mental Processing Time: This is the time it takes for a person to actually realize something. In our case, to realize that the front wheel has locked.
  2. Movement Time: Once the brain has registered a situation, a person must physically react. For us, that means releasing the front brake lever with your right hand.
  3. Device Response Time: The time it takes for the mechanical device to respond to the human input. Here that means the  calipers releasing the disc.

So that’s what is required to unlock a front brake. The average human reaction time to audio stimulus (the sound of a locked front wheel) is 0.17 of a second. The time to then fully release the front brake is around 0.11 seconds. And the time for the bike to respond would be close to 0.02 seconds. That’s a total time of 0.30 seconds to unlock a brake – best case scenario.

But guess what? It only takes between 0.2 and 0.7 seconds to cause a crash from a front brake lock up. Once the gyrostatic forces of the bike reduce and the motorcycle starts to oscillate around its axis (those are fancy sounding words for how a motorcycle stays upright at speed), the bike becomes unstable and falls over.

So, at best you can unlock a front wheel in just under a third of a second. But even that might not be enough to prevent a crash when it only takes as little as a fifth of a second for a crash to occur.

Bosch ABS

Learners shouldn’t have ABS because it means they don’t properly learn how to brake.

This is another classic phrase you often read or hear. It’s a bit of a chicken and egg situation, because if a new rider doesn’t have ABS, they may not build up the desired skill necessary to brake properly when they first need it, resulting in a crash that may put them off bikes prematurely.  Whereas if they had ABS that same situation might be forgotten as just a ‘moment’ and they’ll continue to gradually gain the required skills.

I suppose there’s a touch of logic to the idea it in that a new rider may not bother learning how to brake properly if they have ABS, whereas a non-ABS bike would force them to learn.  Again, this misses the point that ABS is only ever activated if the onboard sensors detect a locking wheel. Practicing to learn on a bike with ABS is the same as one without – it’s just that the ABS is a backup. I would argue that the same people who don’t bother to properly learn or practice braking would do so whether their bike had ABS or not. Here’s a great summary from Bosch, one of the largest suppliers of motorcycle ABS systems on how one should brake on a bike with ABS:

The first rule of braking with ABS: brake as though you did not have ABS.

  • Begin braking using the foot brake as far as possible.
  • Pull the brake lever quickly, but not abruptly. Once the brake pads have fully engaged, increase the braking pressure quickly, and in significant amounts.
  • When performing a full braking maneuver, brake on straight course within the ABS control range. Depending on the model, you can tell that the ABS has kicked in through a gentle pulsing on the hand and foot brake levers, as well as a tacking noise.
  • When performing a full braking maneuver, always disengage the clutch at the same time.
  • When braking in bends, increase the braking pressure gently to prevent the front wheel from slipping to the side.
  • Always pay attention to the rear of the motorcycle when performing a full braking maneuver. If the rear wheel lifts up, you should reduce the braking pressure on the front wheel as quickly as possible.

All those above points are the exact same way you brake, ABS or no ABS. There is not a differing skill set.

Bosch ABS