tettnanger said:
I recently purchased a used TT and have used it exactly one time.? Everything went well and in the next few weeks I'll be using it a lot.? One question I had though concerning tire pressure.? The owner's manual said that I should inflate my TT's tires to their maximum PSI.? This seemed kind of strange to me and definitely not what you typically do for a car or truck.? I did what they asked and didn't have any problems.? However, the manual also said to overinflate my tow vehicle's rear tires.? I don't recall the exact amount amount of overinflation they recommended (I don't have the manual in front of me), but I think it was something like a x # of PSI on top of the normal PSI.? I didn't feel comfortable doing this on my tow vehicle.? Is this normal and do most of you out there do this?
thanks!
Beg to gently and slightly differ with Gary. On a trailer, ride is irrelevant, there is no one in the trailer to "enjoy" the ride. A tire is rated to bear its maximum load at that pressure, lesser pressures lesser loads. And yes there are tables that give a pressure vs. load figure for an acceptable range of pressures. However, for a bloody trailer that is cutting things awfully fine. I just use the max load pressure in all axles.
As regards the truck tire inflation, the recommendation to raise the pressure of the rear tires should be unecessary just from the aspect of the trailer's presence. A weight distributing hitch system does just what its name suggests -- it distributes the tongue weight of the trailer evenly over the front and rear axles. It returns the relationship of the axle loads to the same proportion as before the trailer is hitched on.
What raising the pressure of the rear tires over the front does is to increase the
understeer of the truck. That is the truck will try to steer
out of turns. Reducing the pressure relative to the front increases
oversteer. That is the truck will steer
into turns. Understeer is the more desirable condition in a truck and in fact in most street vehicles. A vehicle that oversteers tends to feel, and be, unstable responding disportionately to steering inputs. A vehicle that understeers responds less to steering inputs and wants to resist turning motion. In extremes it will 'plow' into turns. This is safer than an oversteer situation where the vehicle snaps in to the turn. Snapping into turns is great in a sportscar -- it is really bad in a loaded truck.
OK where this leaves us is that you should follow the
truck mfr's. recommendations on tire inflation and the differential between front and rear.
Myself, since my mfr recommends no differential, I just inflate to the maximum sidewall pressure. I am using all terrain flotation gumballs with a LT rating. These have stiff 4-ply sidewalls so that a max inflation does not do too much to an already stiff ride. But then your experience may differ.
So