Final answer:
To start a heavy vehicle with a manual transmission on an uphill grade, use the 'handbrake start' method which involves balancing static and kinetic friction for a controlled start without rollback.
Step-by-step explanation:
Starting a Heavy Vehicle on an Uphill Grade
When putting a heavy vehicle with a manual transmission back in motion on an uphill grade, it is important to use a technique that ensures safety and minimizes stress on the vehicle. One good rule to follow is to use the "handbrake start" method. To execute this technique:
Make sure the handbrake is applied firmly.
Press the clutch and put the vehicle into the starting gear, which is usually first gear for heavy vehicles.
Apply revs with the accelerator pedal to the point where the engine is just above idle to prevent stalling as you set off.
Gradually release the clutch until you reach the biting point where the vehicle begins to want to move forward, then hold it at this position.
Carefully release the handbrake while holding the vehicle with the clutch's biting point, keeping the revs steady.
As the vehicle begins to move, smoothly release the clutch fully and apply more accelerator as needed.
This method balances the static friction between the tires and the road surface with the kinetic friction that will occur once the vehicle is in motion, preventing rollback. It also ensures that you have maximum control over the vehicle as you start to move and can modulate braking and accelerating for a smooth transition. Remember that uphill starts require more power and careful control due to the effects of gravitational potential energy working against the vehicle's movement.