Steering Wheel vibration only at certain speeds.

Make sure your tires are balanced and check for defects in them. Also make sure that the front steering parts are not worn, IE tie rod ends and ball joints. Might need to look at adding a steering stabilizer if nothing else is found to be bad.

If the steering wheel is vibrationg it may be that the wheels need balancing. If the whole vehicle is shaking you need to check that wheel bols are properly tightened first. You might need to get steering/suspension checked .... before there is a bad fault developing

Have your tires checked for tread separation and your wheels checked for balance. Out of balance tires will go through harmonics such that at one speed it will vibrate a lot more than at another (higher or lower) speed.

That turning of the steering wheel puts lateral pressure on CV joints. IT can also put a load on the axel bearing. If the vibration stops then you have an idea where to look. IF it does not stop then it is most likely tires.

If you are turning the steering wheel all the way to the "lock" position, you are probably putting too much pressure on your power steering pump and you are most likely getting som drive-belt slippage.

If you get a bad vibration in your steering wheel at low speeds without braking it is either a bad tire or a bad rim. If you get a vibration at speeds around 45-50+ and goes away you probably have a balance issue. If the vibration only occurs while braking then your rotors are warped. If low speeds it shakes i'd take it to a shop to check your tires.

Tie rod ends do not have bushings (ball and socket like your hip). If vibration begins at 50-55 but goes away at slightly higher speed, it could be caused by wheel balance. Once balance has been checked jack up each front wheel and shake them back and forth and check for any loose steering components. If reasonably tight, My guess is that you have a bad hub bearing. If you don't know how to change them, get a manual to guide you (chiltons or haynes are OK for this). Pretty much it is a bolt out bolt in procedure and not terribly difficult except that sometimes the hub is rusted in and is a bear to get out. Need any help with that, just ask.
Note...many bad hub bearings show no obvious defects...but can create a strong vibration...just determine which side is noisy and change it. Scrapyard parts are inexpensive and generally fairly reliable as replacements.

check tyres for wear-wheel balance needed if visibly ok-have a wheel alignment after a tyre rotation-best even tyres to be put on fronts-they will carry out a safety check all suspension and steering before doing the wheel alignment

if its more of a whining its your power steering pump.

if your vibration comes and goes with different speeds, most likely problem is balance in tires/wheels. a bent wheel often vibrates more with higher speeds. if the vibration is stong in the steering wheel, the problem is normally in the front end, if you feel in more in the seat or body of the car then look to the rear end.