These pressure springs by Polini increase pressure by between 3% and 18% over the originals and are thus ideal for easy tuning. The spring has the task of pushing the pulley in the rear converter onto the v-belt. But it also produces the counter pressure that allows shifting at the variator. A stronger spring is necessary on tuned engines as otherwise the v-belt begins to slip. The spring is always in close contact with the Variator. If a different spring is installed, the variator must also be adapted. Spring loading original: 40 / 50mm / kg Polini spring loading: 40 / 63mm / kg wire diameter: 5.2mm overall length: 85mm. Inside diameter: 49.4mm number of coils: 5