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Tires
inflated to match the load they carry provide optimal
handling while preventing premature wear.
 In
the last issue we went over how to weigh your combination
or motorhome on a truck scale. Many people weigh their
units just to check and see if they are overloaded,
but accurate weight information can helpful in other
ways as well.
In the old days the tires on RVs were often borderline
at best, so there was little question about what pressure
to carry. You just kept them as hard as possible.
Every trailer has a GVWR sticker which lists the tire
pressure, but this pressure is what is necessary with
the tires loaded to their maximum weight capacity.
What we often run into now are tires that have much
more capacity than they need. When a tire is run at
its maximum pressure but is carrying far less than
its maximum load, the tire will wear in the centre,
have less traction and be harder riding. The ideal
is to have the tires inflated to properly match the
actual load they’re carrying.
This was brought home to me last summer we took a
33-foot HitchHiker fifth wheel on vacation with G-rated
tires, which will carry 110 PSI. The combination seemed
fine on a short test drive, but after about 100 miles
we noticed that the ride was somewhat aggravating.
I drove to a scale and weighed the combination. The
next morning when the tires were cool, I adjusted
six of the eight tires on the rig. The trailer tires
were at 105 PSI, but it turned out that 82 PSI was
all that was required for the load they were carrying,
The back tires of the truck had 80 PSI and that was
close enough to be correct; the front tires had 65
PSI in them but only required 40 to carry the 3,600
pounds on the front axle (I always leave some margin
for error when adjusting the fronts tires on the truck).
So I took the front truck tires down to 45 PSI and
the trailer tires down from 105 PSI to 85 PSI. That
20 PSI difference may not seem like much of a change,
but the improvement in the ride was immediately noticeable.
Even the family, who had no idea I had changed anything,
commented on how much smoother it was. Later on the
trip we were running in 100 degree temperatures and
the tires never ran warmer than 135 degrees. With
45 PSI in the front tires of the truck, steering feel
was a little less direct than I would have liked,
so I experimented a bit finally, settling on 52 PSI
as being optimal.
... (with handy charts "Load/Inflation Information
For RV Tires")
(Read Andy's full article in the magazine.)
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