機器
aluminum
background
bicycle
bicycle chain
bicycle parts
bike
biking
chain
chrome
circle
closeup
cycle
derailleur
equipment
frame
gear
gearshift
industry
iron
machinery
macro
mechanism
metal
metallic
outdoors
part
pedal
pedal system
race
rubber
rust
sharp
shift
shiny
spoke
sport
sprocket
star
steel
technology
teeth
tire
transport
transportation
vehicle
wheel