right, theoretically the stiffer the frame / booster combo the more power should be utilised in stopping the wheel, however the more flexy, the more pwer is effectively wasted.... However, zoo pitbull 04; okay braking performance with an rb booster, better without woodstock; shite brake without, okay with coust; shite with, good without zenith; good without, havent tested it with, although i will tonight and see what difference it makes... Maybe some physicists / engineers can shed some light on this conundrum?