Surly's Trailer Hitch/Yolk Assembly is the correct hitch for Surly's Bill and Ted Trailers (sold separately). This fine chromoly hitch securely and quickly attaches to your bike using the included proprietary quick-release skewer. Or, if you have a bolt-on rear wheel, you just bolt the hitch onto your rear axle. The hitch fits most bicycles whether they feature full suspension, disc brakes, rear racks and fenders, or you name it. And it works with bicycles with wheels as small as 20 inches and as large as 29 inches, while always keeping the trailer bed level with the ground. The hitch also adjusts to accommodate rear hub widths from 120 to 145mm and allows you to align the centerline of the trailer on the centerline of the bike for easy pulling. Maybe best, the hitch lets you remove the trailer quickly and easily when you don't need it. Plus, by putting hitches on all your favorite bikes you can easily move the trailer between bikes!