The BMW drive and serpentine belt is made specifically to transfer the kinetic motion supplied by the harmonic balancer to all of the other pulleys located at the front of the engine. The serpentine belt is the new type of belt system now being used on all BMW models. This replaced the cumbersome and complicated multiple accessory drive belt system used in the past. There are many advantages of using the serpentine belt system over the previous type. One of them is the reduction in the time required to change this belt. With one point of tension being applied, the removal now only takes about 30 seconds. Another advantage of having a serpentine belt is that tension is applied evenly over all of the pulleys. No longer is there a danger of over stressing any of the pulleys, especially the alternator pulley and prematurely wearing out the bearing because the tension is too great. The inspection of the BMW drive and serpentine belt is also very easy to inspect. By slowing rotating your BMW engine, the entire surface of the belt can be inspected by a qualified technician or owner of the vehicle. An inspection should look for cracks, stretch marks, and missing portions on the belt. If any or all of these are seen, it would be advisable for the accessory drive and/or serpentine belt to be replaced with a quality replacement. The replacement of the drive belt on your BMW is part of the important periodic maintenance that should occur on a regular basis. This will ensure your vehicle is safe for you to use when you venture onto the roads that cover the American country side and urban areas.