Athletes on a standard bicycle with mild-to-moderate impairment, e.g. a single below-knee amputation or mild coordination impairment.
C4 athletes ride a standard bicycle and have a mild-to-moderate impairment, such as a single below-knee amputation ridden with a prosthesis, or mild coordination problems. Their impairment has a smaller impact on cycling than for C3 riders. The C4 and C5 classes are frequently combined into a single C4-5 race.