Progressively wound fork springs from YSS in a firmer design than the original. The YSS fork springs are made from high-quality silicon spring steel. This allows for a reduction in wire thickness, making the spring more active and slimmer, while effectively preventing torsion of the spring.To minimize noise and improve oil flow in the fork, the springs are fully polished and ground at both the top and bottom.The delivery includes 2 springs for a complete fork conversion.Technical Data:Spring Type:   Progressive Length:   540 mmDiameter 1:   39 mmSpring Rate 1:   9.0 N/mmSpring Rate 2:   11.5 N/mmAir Chamber Left:   160 mmAir Chamber Right:   160 mmRecommended Viscosity:   7.5W Manufacturer:   YSS