back view of the athlete leg inline with rear derailleur and cassette sprokets.

active and athlete back bicycle bicyclist bike cas cassette chain change cleat closeup cogs cogwheel control cyclist derailleur detail foot frame gear gears gearshift hold horizontal image indoor inline leg lever male man multiple partial pedals racer ratio rear red road shifter shifting shoes speed spoke sport sportsman sportswear sprocket sprokets system the transfer transmission transport variable view white with