Why does the right pedal on a bicycle have a right-hand thread and the left pedal a left-hand thread?

Answer

Hi Ronny,

Indeed, by adjusting the direction of the wire, the two pedals tighten themselves when pedaling the bike.
Due to the effect of temperature differences, vibrations … the pedal could come loose during cycling, if this is not taken into account. The jamming of the roller bearing in the pedal further enhances this effect.

Kind regards,
Luc.