nose of trailer made contact with cab of truck

The simple fact is to turn sharp up to 90 degrees, with a square nosed 5er. You need the pin to be at least half the width of the 5er back from the cab, less than that it will make contact at less than 90 degrees! If you have a short bed and have between 48" to 50" between pin and cab, the pin is likely aft of the rear axle.