A driver pulley assembly for a continuously variable transmission (CVT) includes a roller weight guide, having an inner and outer periphery, adapted to be mounted on the main shaft of the CVT. A plurality of ramp windows extend radially along the roller weight guide. A pair of guide rails extend along opposite edges of each ramp window. A plurality of roller weights, mounted on the pair of guide rails, is adapted to move along the pair of guide rails in a radial direction of the roller weight guide. A ramp structure, coinciding with the ramp window, extends in the radial direction of the roller weight guide and abuts the plurality of roller weights. The roller weighs are adapted to move radially outwards along the ramp structure with increasing rotational speed of the roller weight guide. The ramp structures have ramp profiles. CVT systems and vehicles including the driver pulley assembly are also included.