at what speed gear should be changed. normally it depends upon engine sound. what is best for engine so that there is no load on engine. i used to change gears for my Mehran at following speed.
like 1 gear (Speed 0-10KM)2 gear (Speed 11-35KM)3 gear (Speed 35-60KM)4th gear (Speed above 60KM)
i am curious about 2nd and 3rd one should it be
man just don't rev it to much on gears and speed as u change is prefect
when engine start making noise u can change tha gear, after driving for sometime, u ll understand whats the best time to change them.
Different terrains, different gear ratios.Different weather, different gear ratios.Different cars, different gear ratiosDifferent fuel system, different gear ratiosDifferent drivers, different gear ratios
Conclusion: Experience will let u know
As said by Eco Driving experts, Change to a higher gear as soon as possible.