As already commented you can rotate the mesh in 3D modeling software.
A faster way would be to parent the GameObject that represents the wheel under another GameObject, which will be acting as a pivot then. Just position it at the exact position of the wheel GameObject, but with a the desired rotation.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…