How much speed should be reduced when downshifting from 4th gear to 2nd gear?

[VanLaura]

When downshifting from 4th gear to 2nd gear, the vehicle speed should be reduced by at least 20 kph, bringing it within the 20 to 30 kph range, which is generally suitable for 2nd gear. This is the conventional method for deceleration. However, if the purpose is to downshift for increased torque and acceleration, the speed does not need to be reduced. You can directly shift to 2nd gear, but it's important to blip the throttle before releasing the clutch after the shift to raise the engine speed to match the current vehicle speed, preventing noticeable jerking. For example, when in 4th gear at 60 kph with the engine at 2500 rpm, shifting to 2nd gear would require increasing the engine speed to around 4000 rpm. Releasing the clutch at this point ensures a smoother downshift.