Curt 18031 Trailer Hitch Securely holds up to four bikes with a max capacity of 180 lbs. Towable shank allows use of the bike rack while towing a trailer Towable shank accepts up to 2,000 lbs. GTW and 200 lbs. TW 3/4" trailer ball hole accepts most 1 7/8" or 2" trailer balls Bolt-on arm extensions adapt capacity from two to four bikes