In the old days, you would drive at 30 in top gear (at that time, 4th).
Modern engines, more gear ratios and traffic levels demand a different approach.
I would not attempt to drive 30 in fourth, always third for me, and that also has the benefit of being able to judge your speed by the sound of the engine.
I always adopt the principle of: 30 in third, 40 in fourth and 50 in 5th. |