What tyre pressure should I use?

Based on FIAT's recommendation, your INTERSTATE motorhome should have tyres inflated at 80PSI (5.5 Bar). The is a silver label located in the driver's side door jam that refers to the pressures. 

Should the pressure drop below 50PSI, you will get a warning on the dashboard. To remove the warning, you must inflate the tyres to over 55PSI. 

Note: Different tyre pressures can affect each vehicle differently; many factors, such as the weight the vehicle is carrying and external temperature, affect this. Inflating tyres to 80PSI will usually improve tyre wear while deflating slightly will improve comfort but could result in uneven wear.