Have the tires balanced and rotated.
Tires need to be balanced
wheels off van raised engine shakes side to side at 40 kmh
One or more tire out of balance, a bent wheel, or defect in a tire.
Your rims are bent and/or your alignment is off. Bent rim, bad tire, loose suspension/steering component.
cuz
its chasis could be loose or its just old chasis being he thing that holds the wheels to the car.
Tire out of balance, failed u-joint in drive shaft, engine misfire, transmission malfunction,
I needed new brakes when my 2003 Vue shook at 50mph. Once I had the back brakes changed the shaking stopped.
40 km/h is 24.8548 mph
40 mph = 64.4 kph
Average speed is 50 mph [(40+60)/2].
An electric moped will not be able to go 40 MPH.