Load transfer
Braking transfers load forward, acceleration transfers it rearward, and bumps rapidly change the load on both wheels.
Wheel loads keep changing
The combined center of mass of the motorcycle and rider sits above the tire contact patches. Acceleration and braking redistribute load between the wheels, which is visible in the suspension's movement.
Suspension movement shows load transfer
The front suspension compresses under braking, and the front end becomes less loaded during acceleration. Bumps change wheel loads even without any throttle or brake input.
Available grip depends on the current load
A more heavily loaded tire can transmit more force, but its capabilities still depend on the surface and tire condition. The more grip needed for cornering, the less remains for braking or acceleration.
Brake, accelerate, and change your line smoothly
The more smoothly you begin these actions, the smaller the sudden load changes and the easier it is to feel the approach to the grip limit.
Sources · 1
- Motorcycle Operator Manual
Basic Vehicle Control, pp. 10–13
Used for: Under braking, load transfers forward.
Open source
The front end takes more load
Under braking, the front suspension compresses, the front tire takes more load, and the rear tire becomes less loaded.
Build braking force progressively
As the front tire takes more load, you can increase braking force. Start braking smoothly, then progressively build the pressure.
Do not grab the brake
Grabbing the brake hard from the outset loads the front tire and suspension too abruptly. On a poor surface, the grip limit is reached even sooner.
The rear wheel carries less load
Hard braking reduces the load on the rear tire. Pressing the rear brake abruptly makes it easier to start a slide or trigger ABS.
Engine braking does not create extra grip
During strong deceleration, the rear tire becomes less loaded and can transmit less braking force. The rear brake and engine both act through that same tire. If their combined braking demand exceeds the available grip, the wheel will lock.
Sources · 1
- Motorcycle Operator Manual
Basic Vehicle Control, pp. 10–13
Used for: Increase force at the front-brake lever as the wheel loads; the rear wheel unloads.
Open source
The rear end takes more load
Acceleration transfers load rearward: the rear tire becomes more heavily loaded and the front end becomes lighter.
The front wheel becomes more sensitive
Under strong acceleration, the front wheel carries less load and reacts more strongly to bumps, ruts, and abrupt hand movements.
The surface still limits driving force
On sand, wet road markings, or another slippery surface, an abrupt throttle input can make the rear tire spin, even with the increased load on it.
Add drive smoothly
Rolling on the throttle smoothly transfers load from the front wheel to the rear progressively. That makes it easier to notice the start of wheelspin or feel the motorcycle move onto a wider line.
Bumps change wheel loads quickly
Over a crest, through a pothole, or across a series of bumps, the wheels quickly lose and regain load, even with unchanged throttle and brake inputs.
Avoid abrupt inputs over a bump
Braking abruptly, opening the throttle abruptly, or gripping the handlebars rigidly can make the motorcycle rock more over a bump.
Keep your grip relaxed
On a poor surface, support yourself with your legs rather than putting all your weight on the handlebars. Relaxed arms interfere less with the front wheel and suspension as they respond to small bumps.
Adjust braking and drive in advance
It is better to finish the main braking and changes in drive before reaching a bump. Avoid abrupt throttle and brake changes while crossing it.