Tires: Front tire inflation for truck with camper, Tire Pressure

Question
Barry:
I have a Ford F350 Diesel that I carry a camper on.  The placard on the door post states the proper inflation at 55lbs front and 80lbs rear. I have taken the truck/camper over scales and partly because of the weight of the diesel engine the weights are 2170Kg front axle and 2370Kg rear axle. It seems strange that with a difference of only 200Kg the front tires are inflated 25lbs less.  With the camper on the truck the profile of the rear tires looks ok but the fronts look under inflated. If I raise the pressure in the fronts to 70lbs the profile matches that of the rear.
Would you stick to the placard inflation settings or inflate to match the actual load.
Thanks.
Mike


Answer
Mike,

Look at the placard again.  There should be the letters "GAWR" with a value for the front and a value for the rear.  GAWR stands for Gross Axle Weight Rating - the maximum weight the axles are designed for.  You should NEVER exceed these values.

Also notice the letters "GVW" - Gross Vehicle weight.  This is the maximum the vehicle is designed to weigh.  If you add the GAWR's together, you'll find the sum is greater than the GVW.  This means the vehicle's weight can be slightly unevenly distributed.

For folks who need simple, easy to understand and remember answers I will always tell them to use the placard pressure.

But for folks who can deal with more complex answers - and it appears you fall into this category - I think that a bit of overinflation may be good.

A word of caution.  You may find the vehicle may not behave in a predictable manner with the 70 / 80 pressure split - and you may find a 70 / 90 pressure split more to your liking.  I would not recommend you use a pressure lower than the placard values.