Promocycle: Some old but good studies on braking

[Motofool]

http://www.promocycle.com/etudes-eng.html

"RISKS ARISING FROM A LOCKED FRONT WHEEL
Locking of the front wheel must be avoided at all costs during hard braking because it leads almost automati-
cally to a loss of directional control and a sideways crash if it persists longer than a tenth of a second. Fear
engendered by this physical reality means that the majority of motorcyclists under-utilize the capacity of their
front brake, especially at the start of braking. Thus it is of paramount importance to become proficient at the
start of braking because the distance traveled is relatively greater than at the end of braking.
.........
EFFECTS OF DECELERATION FORCE
The mean deceleration for the group of 298 passes braking from 100 km/h to zero wa -0.898 g in a mean time
of 3.18 seconds. During these more than 3 seconds, the rider had to manage his braking while subjected to a con-
siderable deceleration force against his arms and hands which must in large measure support his upper body. A
simulator designed to recreate this force would have to incline the motorcycle on its front wheel at an angle of
64 degrees.

THE EQUILIBRIUM STAGE
Each emergency braking maneuver is preceded by a stage of stabilizing the motorcycle. Although it may be
very short, it is no less important despite the fact that it is little covered in the literature. Even when the motor-
cycle gives the impression of rolling in a straight line, the rider makes constant adjustments to maintain equilibri-
um among different forces and the chosen trajectory. At the moment of emergency braking, this equilibrium
must be perfect and be maintained for the length of the braking maneuver.

PRISONER OF POSTURE
Once the emergency braking procedure is started, because of the forces engendered by deceleration on the
arms and hands, the rider is a prisoner of his choice of the number of fingers employed on the front brake lever.
During the course of intensive braking he must not modify the position of his fingers.

DISTANCE VERSUS TIME
Although there is a correlation between braking distance and time, it
is not absolute. Thus the quickest stop from 100 km/h recorded during these tests lasted only 2.70 seconds but
covered 37.68 meters. The shortest stopping distance recorded was 36.95 meters in an elapsed time of 2.75 sec-
onds. This slight difference highlights the importance of an effective start to the braking procedure at the
moment when the distances traveled are greatest.

USE OF THE CLUTCH
Downshifting:
Should one downshift during emergency braking?
Some observers maintain that it is preferable to downshift during hard braking in order to be in a position to
accelerate again if the situation demands it. Others claim that during an emergency stop the rider must concen-
trate exclusively on braking and that downshifting can only increase braking distances.
We devoted an entire day (June 20, 2003) to this variable during which we recorded 77 tests with two differ-
ent riders on the same motorcycle.
The mean stopping distance for 31 tests during which the riders were instructed to downshift was 43.17 meters
compared with the general average of 41.71 meters for the group of 298 tests.

IDEAL SEQUENCE
These figures indicate that the ideal sequence for the most effective emergency braking possible is to succes-
sively close the throttle, apply the rear brake, apply the front brake and de-clutch completely."

[Motofool]

[Panda]

Good stuff Herman, thanks.

[Motofool]

[Motofool]

[ally99]

Liked it just as much the 2nd time I read it.
Well worth the read!

[JohnnyBravo]

Braking can def get hairy when done at the limits so far so good