Originally Posted By: mjoekingz28
On my door jam it states to use 50f/80r tire pressures. I aired them up to 40-45psi and figured i would use the door's recommendation when loaded to the gills.
It rides pretty good at 40-45.
First, you should read your owners manual and see what it says there.
Second, just pulling a number out of thin air is just a bad idea. Do some math and figure out what the vehicle manufacturer was intending when he specified the inflation pressure he did. Then figure out what MIGHT be an appropriate alternative.
I am NOT a fan of using inflation pressures different than what the vehicle manufacturer states.
First, It has been 14 years since the Ford/Firestone thing - and everyone involved learned quite a few lesson from that - and one of those was being careful not in specify low inflation pressures.
Second, ALL vehicle manufacturers test their vehicle at the inflation pressures specified on the doorframe. If you use something different than what is their, you are going into uncharted waters.
Third, one of the things that pops up regularly is that when a vehicle specifies different inflation pressures front to rear, then in order to maintain the handling characteristics, you need to maintain that relationship. That may mean that you can't quite do what you think you can.
And lastly, if you are going to do something different that what the vehicle manufacturer specifies, for heaven's sake, do some investigating. Test the handling, look at pressure buildup, calculate the load carrying capacity. Don't just do it and hope nothing will happen. That method has a way of turning people into Darwin Award winners.