Nice captures, just the right amount of background blur and blurring on the wheels to give a sense of movement, whilst the bikes/riders are nice and sharp. My only crit is that they all look a little dark, so assuming it was an overcast day. Might have been tempted to lift them a bit during pp and maybe next time, use similar settings but open the aerture a little wider if pos, and if not, push the iso up a notch just to get a bit more light. However, they look pretty damn good for a first effort