You need to see a mchanic
BADLY!!!!
Sounds like a loose wheel But it could be a bad tire with a "Lump" in it. Both are very dangerous so you need to have your car checked and repaired.
Warped rotors is the most likely cause. Seek professional help.
you steering wheel starts shaking because you probably have warped roders your shaking will get worse at higher speeds and when pressing the brake
What is the answer
1. out of balance tire 2. Steering out of alignment 3. bad wheel bearings
Sounds like it may be a rear tire with a hard spot or a patch of tread missing. You said nothing if the steering wheel was shaking so if I may, I suggest you move the rear tires to the front and see what happens, if it is the tires you should feel something on the steering wheel.
Tires need to be balanced and re-aligned
Tire out of balance, bent wheel, defective tire, or worn steering parts.
At highway speed, tire out of balance or bent wheel. When stopping, warped rotor.
If your steering wheel is shaking you probabley messed you wheels or axel up
A shaking steering wheel means something is wrong. Can be a tire out of balance, bent wheel, or suspension problem. Whatever it is, the shaking it putting stress on other parts and can cause other things to wear out. It is especially hard on wheel bearings. have this diagnosed and repaired asap.
That is typically a wheel balance problem.