The optimum tightening torque 
for a worm gear hose clamp depends on the diameter and the material of the hose.
From experience we know that the optimum thightening torque is for rubber hoses with a diameter up to 25 mm is about 2,5 Nm.
If the recommended tightening torque
value is significantly exceeded the hose becomes compressed, thus endangering the seal.
The below torque gauge indicator shows the importance of exactly defined tolerance ranges in respect of idle torque (free turning torque) and tightening torque. If these ranges overlap the function of the clamp would not be guaranteed. The degree of efficiency of the clamp is constant when these values remain constant.
Correct fitting:
Incorrect fitting caused by excessive tightening:
