section_path: Maintenance and repair/Maintenance
section_name: Maintenance
paragraph_text: Maintenance
  
  The most basic maintenance item is keeping the tires correctly inflated; this can make a noticeable difference as to how the bike feels to ride. Bicycle tires usually have a marking on the sidewall indicating the pressure appropriate for that tire. Bicycles use much higher pressures than cars: car tires are normally in the range of 30 to 40 pounds per square inch (210 to 280 kPa), whereas bicycle tires are normally in the range of 60 to 100 pounds per square inch (410 to 690 kPa).
  
  Another basic maintenance item is regular lubrication of the chain and pivot points for derailleurs and brake components. Most of the bearings on a modern bike are sealed and grease-filled and require little or no attention; such bearings will usually last for 10,000 miles (16,000 km) or more. The crank bearings require periodic maintenance, which involves removing, cleaning and repacking with the correct grease.
  
  The chain and the brake blocks are the components which wear out most quickly, so these need to be checked from time to time, typically every 500 miles (800 km) or so. Most local bike shops will do such checks for free. Note that when a chain becomes badly worn it will also wear out the rear cogs/cassette and eventually the chain ring(s), so replacing a chain when only moderately worn will prolong the life of other components.
  
  Over the longer term, tires do wear out, after 2,000 to 5,000 miles (3,200 to 8,000 km); a rash of punctures is often the most visible sign of a worn tire.