Rotation values problem


I have a wheel initially rotated at 0,0,0 euler angles (the front is oriented towards z-). By pressing the up key RelativeTorque is added, so that it rotates the wheel around the x axis by a certain amount. But what I noticed is that the other global euler angles (y and z) are changing too. The x rotation firstly decrements from 360 to 270 and when it reaches these 270 degrees, the y and z angles instantly become 180 degrees. The process of rotation continues - the x angle starts to increment from 270 and when it reaches 90 degrees y and z angles instantly equal 0, then the x angle decrements from 90 degrees to 360 degrees. And the process starts over. It all takes place with only the up key pressed.
This is extremely frustrating, as I want to add Torque around the y axes, but the y angle changes resulting in irregular rotation around all global axes.
Does anyone know any solution for this problem?

If you are using a rigidbody try locking the Rotation of the axis’s you don’t wish to rotate. You may want to look at this instead of torque.