c# - Car wheels not rotating properly, how to fix? -

i have basic car model. far have managed wheels rotating in 1 of 2 ways:

• the wheel rotates on local z axis when turns
• the wheel rotates on local y axis when drives forward or backward

they both work fine, cannot them both work @ same time. absolutely stumped , starting piss me off! have been trying follow video (https://www.youtube.com/watch?v=0jvj2fmvbbs) , have following error:

• cannot modify value type return of 'unityengine.transform.rotation'. consider storing value in temporary variable.

could take @ code , show me i'm doing wrong? in advance.

code:

public wheels[] wheel; public float enginepower = 20f; public float turnpower = 20f;  void fixedupdate () {     float torque = input.getaxis("vertical") * enginepower;     float turnspeed = input.getaxis("horizontal") * turnpower;      //4 wheel drive     wheel[0].move(torque);     wheel[1].move(torque);     wheel[2].move(torque);     wheel[3].move(torque);      //front wheel steering     wheel[0].turn(turnspeed);     wheel[1].turn(turnspeed); }  void update () {     wheel[0].transform.rotate(0, 0, wheel[0].getcomponent<wheelcollider>().rpm / 60 * 360 * time.deltatime);      //only 1 wheel shown simplicity      wheel[0].transform.rotation.y = wheel[0].getcomponent<wheelcollider>().steerangle - wheel[0].transform.rotation.z; } 

the "rotation" variable of transform quaternion trying in second line of code in update break rotation. instead, you'll have use transform.rotate again , access z value of rotation transform's local euler angles.

wheel[0].transform.rotate(0, wheel[0].getcomponent<wheelcollider>().steerangle - wheel[0].transform.localeulerangles.z, 0);