Some special bikes have rear fenders. This tire block adapter is available for purchase and it raises your bike in the rack so the rear fender does not contact the bike channel.
This block will match your channel width you have ordered.
Rather than load a bike upside down in the rack this block makes it easier so the heavier rear wheel is kept downward. Price is for one block assembly.
It comes complete with longer wheel strap, ss bolts, and instructions.