What causes a shaky steering wheel?

Here are opinions and answers from contributors:
Tires out of balance or the “bushings” (not sure the technical term) are worn in the steering system.
It could be faulty steering dampers. This is a shock that crosses from left to right connecting to tie rod ends. The shock is very firm and you will not be able to actuate it by hand if working properly. usually causes left to right steering oscillation at low to mid speeds.
Warped brake rotors for cars with front disk brakes. The rotor hits the caliper every tire rotation causing a small bump in the steering wheel each time.
Your tires might need to be rotated and balanced.
In my “94” Intrepid it was worn out rubber isolaters which the bolts on the rack & pinion steering mounted through on the firewall. It was noticed at speeds over 35mph & resulted in feeling a violent shaking of the front tires felt through the steering wheel.
Check tires should be balanced, alingned or probably a bent front tire.
Most of the time its only bad front tires now the one guy was right it can be bad brake rotors but what he didnt tell you is there is 2 things for that 1 is the steering wheel shaking when you are braking if so then you have warped rotors another thing when you brake does the car pull to the right or the left if so that will determine what rotor is bad and for but if it doesnt shake while braking that could mean your tires are cupped in the front or there not balanced properly.
Depends when the wheel shakes. If it is during braking then your rotors are warped. If it is durinig normal driving then yes it could be bent rim, loose/worn suspension components. A balance problem is usually indicated by vibration in the vehicle not usually a shaky steering wheel. It may also be that the steering gear is badly worn which causes greater than normal spaces between the meshing parts.
Out of balance wheels, bent rim, shifted belt in tire or other defect in tire including irregular wear (tire rotation under these conditions will on move the vibration felt), loose lug nuts, worn inner tie rod end bushings like mentioned on Chrysler product above, loose mounted or internal play in the rack and pinion steering gear. Wheel Alignment or Front end Alignment will not cause a vibration.
CV joint could cause this.
Or a bent rim, which balancing will not fix.
Check the lug nuts on all your tires. That did it for me.
Shaking could also occur from camber being ofset as well as all! The other answers given above.
Just had the same thing and it turned out to be worn struts which had caused my tire to wear unevenly (flattening one side of the tire). That caused shimmy at higher speeds.
Also try new CV boots or a driveshaft replacement