POLINI Contrast spring 1127809

The contrast spring of the rear mobile semi-pulley is of considerable importance for the variator's adaptation to the power increase under maximum demands.
After installing conversion kits with high torque and power, the drive belt may slip on the pulley, or the rear movable half-pulley may not be able to counteract the movement of the crankshaft-mounted pulley. In these cases, it may be advantageous to install a higher-pressure spring on the rear half-pulley; the two springs manufactured have a higher pressure than the standard spring:
10% BLUE (Maxiscooters)
7% WHITE (Scooter) 50)
15% BLU (Scooter) 50)
In any case, remember that higher-pressure springs should only be installed when absolutely necessary; the best performance is always achieved by using the spring with the lowest pressure that allows power transmission. Indeed, higher-pressure springs tend to trap the belt between the pulleys, increasing belt wear and reducing transmission efficiency. Before replacing the spring, check the belt for wear and ensure the variator is functioning properly.