most of the time bad allignment or not balanced tires. You could also have a bent rim.
Could be motor mounts, the tires out of alignment or out of balance, or the steering needs work.
Vibration of the car/steering which gets bad at a specific speed.
well... there are many different causes for vibrations. The most common cause for steering wheel vibration at high speed is poor wheel alignment.
A bad wheel hub searing can cause vibration on your steering. Loose or broken steering and suspension components can cause vibrations when accelerating, decelerating or changes in speed. Worn tie rod bushings, damaged struts or shocks are common causes of vibration. Drivetrain problems, such as a bad wheel bearing, damaged CV-joint (front-wheel-drive cars), a bent or imbalanced driveshaft (rear-wheel-drive cars) or missing chassis/drivetrain damper weights are all examples of speed-sensitive vibrations.
There is a Technical Service Bulletin out for this issue. The fix is to loosen the trans mount on the driver's side and reposition it.
This can be a warped rotor or tire out of balance. If it only happens when braking it is a warped rotor.
High speed vibration is often an indication of a wheel that is out of balance or a bent rim. It can also be a bent driveshaft or bad U-joint. Vibration when you brake at high speed is almost always a warped rotor on the disk brakes.
tire out of round belt shift bent rim or play in front end components. could be a rotor if it gets worse during breaking it is rotor.
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.
Bowing of the rotor from high speed-high heat conditions at peak operation.
It could be bearing starting to seize on the alternator and reducing the belt speed to the power steering pump.
The speed of the vibration. High speed vibration = high frequency = short wavelength = high pitch. Low speed vibration = low frequency = long waves = low pitch.