Surflogic Surfboard Bicycle Racks | Black | 2021  The new Surflogic Surfboard Bike Rack fits with an easy under seat attachment. It fits all bikes with 25mm to 32mm round seat post. It has adjustable arms for different size boards so no matter what your are riding (fish or performance boards) you will be able to get your equipment from one destination to the next. It has retractable elastic tie downs to safely secure board for a better journey. Features Padded arms for surfboard protection Easy to detach when not in use Lightweight sturdy aluminium frame