Q: Shaking in steering wheel at 120/km

The most common reason for a vibration while driving is a tire issue. The tires may be out of balance, or just worn to the point that they will cause this. Typically, the brakes won’t cause this, unless it happens when you are applying the brakes. It is possible for the wheel bearing to cause a similar situation, but there will normally be an amount of noise heard (usually a roaring type noise). I would suggest doing a visual inspection of the tires first, to see if there is any uneven wear, which could signal that there is a fault in the suspension, or just a need for an alignment. If you feel you could use a hand in either identifying the problem, or repairing the issue, contact a certified mechanic, like those available at YourMechanic.com.