TOTW: Engine braking: cool sound. Poor practice

The riding tips on these pages are my personal opinion about matters related to motorcycle riding. They are not the official position of any organization, and are for your consideration only. They are not hard and fast rules, they should not necessarily be applied in all circumstances, and they should not be applied without thinking. Always use your judgement and take all current safety factors into account while riding. You are responsible for your riding, not anyone else (especially me). These tips were originally published by a motorcycle riding course, called “Tip of the Week” (the reason for the TOTW in the titles).

How does “engine braking” work?

Should you downshift to slow your bike? Let’s review how it works, why you would want to do it, and why you might not.

Suppose you are riding at a constant speed, then close the throttle. The engine’s inertia will fight the bike’s forward motion and will “drag” the bike to a slower speed. Now do it over but adding a downshift. This forces the engine speed higher and the “drag” will increase.

Why would you do that?

Among riders who believe Engine Braking is an advanced technique (I disagree), you’ll hear several reasons:

  • It’s a habit from driving a standard-transmission car, where it can sometimes be a good practice (e.g. on ice).
  • It sounds impressive. You get a cool “brmmmmmm” from the engine, just like you hear when you watch motorcycle racing on TV. You think racers must be doing it.
  • It’s a challenging skill.
  • It saves wear on brake pads.
  • In conditions where you want to brake using mainly the rear wheel (rare since the front is the more effective brake) engine braking makes rear-wheel locking less likely than using the rear brake.

Why would you not do it?

Despite the attractions above, engine braking is not good practice, for several reasons.

  • It trades brake pad wear for engine wear. Brake pads are made to wear and cheap to replace. Engines aren’t.
  • It applies braking force to the rear wheel (the one connected to the engine). As you will learn from rider training, your front wheel is the important one for braking. Rear-wheel braking will slow your bike, but not much.
  • Your brake light won’t come on, and you really should let the car behind you know you’re slowing.
  • You’re not hearing racers do it. They’re doing something that sounds similar, described below.

Recommendation

You should not downshift to make the bike slow down; you should downshift because the bike is slowing down — so you are remaining in the appropriate gear for the speed you are going. You will adjust the throttle position (using a little “blip”) to match the new engine speed so your downshift is smooth and does not cause braking action on the rear wheel. (It’s this throttle adjustment you’re hearing racers do.) There are two good ways to slow your bike:

Braking. That’s what your brakes are for, and they’re very good at it. As you’ll learn from rider training, use both brakes, using only light pressure on the rear and squeezing the front with sufficient pressure to get the braking effect you want.

Scrubbing. This is the fancy term for just backing off the throttle and letting the bike slow down. If you back off the throttle and then let the bike “coast” to a slower speed, you’re “scrubbing some speed”. It’s a more impressive term than “coasting” — impress your friends with your expert vocabulary.

One more time: downshift to remain in the correct gear. Because you are slowing down, not in order to slow down.


One Comment

  1. First sorry for my English… I’ve an reason for that, I’m french…

    I just spent sometime over your articles. I ride since years and years and years… May to be too much years.
    I ride so much different type of bikes, so much different brand of. as per now my 53 years old and since I’ve started at my 14 years old I guess we can agree that I’ve experienced. I do more or less 20K kms/year… With my HD or my Triumph (or with my very old other bikes – 1932 & 1954) I crossed some much people on bike that surely need tips that I than you for your idea and how this web site is didactic and easy to read.

    But, I’m sad to don’t fully agree about some technical that you not recommends or critics…

    Just two examples, who a bike steers. You know, your article on this missing something really important. On bike, you never turn, you just control the fact that you falling down. That is a better explanation of your picture, and what your tires look after taking wide angles.
    Combination of gyroscopic and centrifuge forces helps the rider to control the fall. When you push on the right bar, you just imbalance the bike. And when then the gyro and centri forces plays to give direction to the bike.

    Second point is about the current article. Again here something important sound’s missing for my point of view. I mean, the mass transfer is completely blinded for your article. Why ?
    As your rightly said, the role of the front wheel and the weight that is on is the most important to keep a cap. But a good spread of the weight between front and rear wheel ensure you the best reaction on the bike in case of unforecasted event. You know, transfer of mass means lost energy, and lost energy means increase of times. Lost of times in bike when problems raising, means crash… So, using your engine to spread the weight to keep a good spread of your wheels si realy not bad. It provide you the insurance that in case of avoiding obstacle is suddenly needs, you will not have too much transfer of mass to negotiate your avoidance… If your taking your breaking system when more 75% of the weight is on the front wheels, you need luck to taking curve without loosing your front wheels…

    No doubt about everything you wrote on your articles covers a good amount of situations.
    But, as you rightly wrote in one of your article, understanding the bike is also understand the physical aspects linked too on every and single situations.
    So just a little point of regrets that sometimes, you go a little bit to strait to the point.

    Cheers,,,

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