First turbo. How tight should it be against wheel? Do I need to change tyre pressure?

[jase_31]

How tight should it be against wheel? Just tight enough so it turns the roller and does slip, or tigher?

Do I need to change tyre pressure?

 

[CXRAndy]

If its a narrow road tyre, around 100 psi.

Pressure on roller, just enough so it doesn't slip. You might get the odd slipping but that's ok

 

[screenman]

Depends if the roller is spring or not.