Useful Terms - Yamaha 2012 TMAX XP500A Service Manual

Useful terms

• Wheel speed:
The rotation speed of the front and rear wheels.
• Chassis speed:
The speed of the chassis.
When the brakes are applied, wheel speed and chassis speed are reduced. However, the chassis
travels forward by its inertia even though the wheel speed is reduced.
• Brake force:
The force applied by braking to reduce the wheel speed.
• Wheel lock:
A condition that occurs when the rotation of one or both of the wheels has stopped, but the vehicle
continues to travel.
• Side force:
The force on the tires which supports the vehicle when cornering.
• Slip ratio:
When the brakes are applied, slipping occurs between the tires and the road surface. This causes
a difference between the wheel speed and the chassis speed.
Slip ratio is the value that shows the rate of wheel slippage and is defined by the following formula.
Chassis speed –
Wheel speed
Slip ratio =
Chassis speed
0%: There is no slipping between the wheel and the road surface. The chassis speed is equal to
the wheel speed.
100%: The wheel speed is "0", but the chassis is moving (i.e., wheel lock).
× 100 (%)
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