Why does my car steering wheel vibrate at high speed?

Vibration of the tire is caused by a uniformity parameter called "variation of radial force". Usually a vehicle's steering wheel will vibrate (called torsional nimble) at a certain speed. This vibration is caused by the harmonics of this radial force. Picture the side view of a tire with different size springs within it. The force of these springs cause a distortion of this force and you feel this distortion in the steering wheel.