Pedals

9/16” x 20 tpi (14.28 x 1.27 mm)

The 9/16” is the most common pedal thread size on the market today and is the size that most manufacturers use for their pedals. Almost all modern adult bikes have the 9/16” pedal with 20 threads per inch (tpi).

½” x 20 tpi (12.7 x 1.27 mm)

This pedal size is much less common than the 9/16” pedals, but bikes are still produced with these sized pedals today.
Typically bikes with these sized pedals are kids bikes, BMX bikes, and cheaper adult cruiser style bikes. If you have one of these kinds of bikes, then it is likely that you have a ½” pedal thread size.