A question from an Airstream owner.
I have a 2020 Ford F250 and an Airstream 33' Travel Trailer. I've read a
lot of discussion about tire pressure, but nothing real current. What I
mean is, the newer F250 door column states for these Michelin tires
now, 60psi front and 65psi rear. The tires max at 80psi on the sidewall
which was my experience with prior year F250's on the door column too,
but the tech at the dealership said they've changed and that with normal
driving you can run 80psi, but harsher ride and you'll run the "middles
out of them."
On to the Airstream. All four tires are Michelin LT225/75R16, Load
Range E. The Airstream sticker says 80psi for these tires. I went up
to my local Dobbs Tire Dealer and he pulled up the Michelin chart for
these tires, and said with a trailer weight on dual axles of between
7980lbs and 8600lbs, you could run the pressure between 60 -- 65psi. I
asked if I would have a problem with tire heat or wear and he said no. I
did put a 3" lift kit on the Airstream, so as to have better clearance
at gas stations and various road conditions. The dealer puts in 80psi,
but from time to time I get popped rivets, (if ride is the cause).
My question is this: With an approximately 8200lb trailer, 1300lb hitch
weight, and just me and some luggage, (300lbs of luggage), what would
you recommend on tire pressure on both vehicles for mostly interstate
driving, despite the door stickers, (if recommended)?
Not sure why you think the information on appropriate tire pressure is different today than it has been for the last 10 years.
Car companies have teams of engineers that work closely with the team
of tire engineers to select tires and inflation numbers that will
deliver the best overall tire and vehicle performance. The consider and
test for ride, handling, steering response, fuel economy and safety in
emergency situations. The inflation on the sticker along with tire
inflation information in the owner's manual should be followed.
Mechanics and service people at the car dealership are not involved with
the selection or testing and evaluation of the new tires that were
selected for the new vehicle. While they have some knowledge I see no
way they can know the performance features of the tread rubber or the
construction features of the body of the tire that was designed,
selected and manufactured for that specific vehicle.
While I am not aware of any similar testing and in vehicle evaluation
on tires for trailers in the RV world, there are still some requirements
the RV Certification Label aka Tire Placard sticker has to meet BY LAW.
Tires selection is the responsibility of the RV mfg. The inflation
specified on the sticker along with the tire type and size must be
capable of supporting at least 50% of the stated GAWR per DOT
regulations for each tire. A few years ago RVIA decided that having at
least a 10% load capacity margin would be a good thing and that having
such a margin should improve tire reliability so the sticker inflation
for the specified tires must provide AT LEAST 110% of the GAWR and
assumes a perfect 50/50 end to end of each axle oad split. So if your RV
is RVIA certified the sticker as applied by the manufacturer must meet
I think a point of confusion
is the wording on some tires concerning the Max Load capacity of a tire
and the appropriate inflation needed to provide that load capacity. Each
tire has an absolute Maximum Load capacity number and that is the
number stated on the tire sidewall. The confusion comes in when people
think that they can obtain more load capacity if they increase the
inflation but that idea is incorrect once the maximum load capacity of
the tire has been reached. While it is possible to increase the
inflation doing so will not increase the laod capacity and that is why
some tires say "Max" inflation but everyone should know or realize that
tires warm up when in the Sun or when driven and that pressure increases
with temperature (about 2% per each 10F) BUT when discussing inflation
numbers or when setting tire pressure we are ALWAYS talking about the
pressure when a tire is at the prevailing Ambient temperature i.e.
temperature in the shade and the tire has not been warmed by either
being in the Sun or being driven on for the previous 2 hours. i.e. "Cold
As an experienced tire design
engineer I can only advise that people follow the car company and RV
company recommendations for tire inflation unless they follow the
specific guidelines provided by actual tire engineers if they want to
fine tune tire pressure based on actual scale measurement and include
the suggested tolerances and margins on load and inflation.
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