Question: what size are bike pedal threads?
Answer: Most pedals have 9/16" x 20 tpi threads. Pedals for one-piece cranks are 1/2" x 20 tpi. Older French bicycles used a 14 mm x 1.25 mm thread, but these are quite rare. French-threaded pedals are commonly labeled "D" and G" (French for "droite" and"gauche" (right and left).