The drive belt system consists of the following components:
|     •  | The drive belt tensioner | 
 
|     •  | The crankshaft balancer pulley | 
 
|     •  | The accessory drive components | 
 
|        -  | The A/C compressor, if equipped | 
 
The drive belt  is thin so that it can bend backwards and has several ribs to
match the grooves  in the pulleys. The drive belts are made of different
types of  rubbers (chloroprene or EPDM) and have different layers or  plys  containing
either fiber cloth or cords for reinforcement.
Both sides of the drive belt may be used to drive the different accessory  drive
components. When the back side of the drive belt is used to drive a   pulley, the
pulley is smooth.
The drive belt is pulled by the crankshaft balancer pulley across the  accessory
drive component pulleys. The spring loaded drive belt tensioner       keeps constant
tension on the drive belt to prevent the drive belt from   slipping.     The drive
belt tensioner arm will move when loads are applied   to the drive     belt by the
accessory drive components and the crankshaft.
The drive belt system may have an idler pulley, which is used to add  wrap to
the adjacent pulleys. Some systems use an idler     pulley  in place  of an accessory
drive component when the vehicle is not equipped      with  the accessory.