Roadstone N Fera SU1 – 245/50R18 (104W) The N?Fera SU1 is an ultra-high-performance tyre to be fitted on passenger vehicles and sporty design. Excellent dry and wet traction are supported by optimum split surface siping. By increasing shoulder block stiffness, pressure distributes evenly and ensures maximum cornering performance. It gives superior grip and excellent handling on the road.