Can't adjust the wheel collider.

Hey everyone !! So I'm new to Unity and i'm working on a bicycle racing game. i made a bicycle and now i want to add wheel colliders to it. I made an empty game object and added a wheel collider to it and then made the game object the child of the bicycle. The problem that im facing is that i cant Rotate the wheel collider so that it fits the wheel. I've tried many things but can't get it right. Any help would be deeply appreciated !!
P.S: i've uploaded a picture.

 

You should ensure that the vehicle's forward direction points to +Z (blue arrow in the position handle). This is the convention in Unity for the "forward" direction overall. If your mesh points in another direction you should create a parent object and add the mesh as child. Then rotate the child so its forward direction matches the +Z direction of the parent.