CE Smith Trailer 13110 Trailer Hub Kit (1" Stud (4 x 4))- Replacement Parts and Accessories for Your Ski Boat, Fishing Boat or Sailboat Trailer 4 studs x 4" bolt circle diameter 1" straight shaft; 1250 lb. capacity 5-9/16" wheel flange diameter 12" maximum wheel size 1.98" hub inner diameter