Change of gear
First gear is for pulling away, but should you tow in fifth?
You don’t need to be a mechanical enineer to understand that you should shift the gears as smoothly as possible while accellerating to cruising speed. Keep in mind that Lewis Hamilton’s fuel is sponsored. Driving like him may perhaps classify you as a good driver, but it will never be economical.
So it’s important to know how high your engine can rev before you shift gears in order not to damage the gearbox. This is where doing your homework comes in.
Take a diesel engine of which the optimal torque, for argument’s sake, is reached at 1 900. The top 20% of the torque curve will therefore be between 1 520 r.p.m and 2 280 r.p.m. You therefore have to paddle that gear lever like a row boat to keep the revs within these parameters.
When the revs drop as low as 1 520 r.p.m, it’s time to shift down and when they reach 2 280 r.p.m, you must select a higher gear. Continue like this until you reach the desired speed – regardless of which gear you are in.
Headwind. When towing, aim to keep your vehicle’s revs in the upper 20% of its torque curve. In this case, between 1 520 r.p.m and 2 280 r.p.m.
Just right. Aim higher. Aim lower. If the specifications on your vehicle state that optimal torque is produced at 1 900 r.p.m, this is where you get the best power. When the rev counter drops to below 20% of the curve, it’s time to select a lower...