Did you know your BMW clutch Disc is really made up of three separate parts? Okay, four if you count the pilot bushing. There's the clutch pressure plate, the clutch throwout bearing, and the BMW clutch disc. The pressure plate and the BMW clutch disc to the work of transferring the power, while the throwout (or release) bearing handles the load when you have the clutch disengaged. When your BMW clutch wears out, it's almost always the clutch disc that's shot. It's the part that contains the sacrificial friction material, and gets sandwiched between the clutch pressure plate and the engine's flywheel.

When you engage the clutch, like at a standing start, the clutch pressure plate clamps the BMW clutch disc against the flywheel. The clutch disc has little springs on its perimeter to absorb some of the force of a rough engagement, and splines on its inner hub that mesh with your transmission input shaft. As it comes up to engine speed, torque gets transferred to your transmission, and you're off like a rocket. Unless, of course, the friction material is nearly gone, in which case you're off like a freight train…sloooowly. Or, if you have oil or foreign material on the BMW clutch disc, you'll get a jerky start no matter how smoothly you engage the clutch. So heed the messages you get from your BMW clutch disc--it's what's putting the power to the ground.