a bicycle mechanic in the workshop holds a cassette from a mountain bike in his hands. bicycle repair

background bicycle bike broken cassette chain circle close-up closeup cog component cycle cycling derailleur detail drive equipment fix freehub freewheel from gear gearing gearwheel hands his holds machine macro mechanic metal metallic mountain mtb new part parts professional race rear repair replacement ring service shiny spare speed sport sprocket steel technology teeth transmission transport transportation vehicle wheel workshop worn