Emergency Braking: Clutch or De-clutch?

What is meant by clutch and de-clutch?

Clutch = engaged (rear wheel is coupled mechanically to engine)

De-clutch = disengaged (rear wheel no longer coupled to engine)

Squeeze clutch lever and engine operates without power being delivered to the rear wheel (de-clutch). Release clutch lever and engine engages rear wheel (clutch).

Two Schools of Thought (there may be more I’m not really sure)

1. Disengage the clutch with the first instance of braking (rear wheel is disengaged from the engine).
2. Leave clutch engaged as long as possible for shorter stopping distance by effectively using front rear and engine braking.

Use of the Clutch

Some riders clutch during emergency braking some riders declutch. It depends on how you were taught. During our basic police motorcycle training, we were taught de-clutch (rear wheel no longer coupled to engine) during braking.

Keep in mind, not every rider using the same technique is going to produce the same stopping distances. I was producing some great stopping distances because I was testing the limits of how much pressure to apply to the front brake. I was the only rider to produce the shortest stopping distances. I was also the only rider to low-side from locking the front wheel (not recommended).

In 2004, the Promocycle Foundation published “Task analysis for intensive braking for a motorcycle in a straight line.” On page 9, the very subject was tested. The thought there was a rear wheel remaining coupled to the engine is less susceptible to lock.

The mean (average) braking distance recorded over 35 passes with the clutch engaged was 41.51 metres (136 feet).

In the 11 passes for which the rider was instructed to declutch, that is to pull the clutch lever and disengage the rear wheel from the engine, the mean (average) stopping distance was 39.95 metres (131 feet).

The rest of the report is an interesting read if you want to look at it click on the link above.

Conclusion

As part of our investigations we often take plenty of photographs (thanks to digital cameras). People want to know what kind of camera we use or what is the best camera to use. My response is always the same, the best camera in the world is the one you have with you.

When you need to take a photo, like right now, the $5,000 Nikon back at the office is of no value. In that situation my iphone camera is the best camera in the world.

Emergency braking is similar. What is the best technique in the world? The one you have with you, or rather, the one you are familiar with. The one you have practiced is going to yield the better stopping distance for you.

Whatever you choose or feel comfortable with is the right technique for you. Practice, practice and then practice some more.