Over-inflate Tires to save fuel?

[ldetsf]

A hitch salesman told me that to save fuel, he over-inflates his TT and TV tires by 5 lbs. I'm sure there are a few opinions out there in this regard. Love to hear them. Also, Lots of controversy about whether to fill TV (truck) tires to max load or unladen load rates when TV is either empty; loaded or partially loaded. Seems at least in part depends on tongue weight. Like to hear your thoughts on this as well. Thanks

[2airishuman]

hi edfos2

we've written entire libraries of info on these topics...
tire inflation pressures
tow vehicle tire pressures
trailer tire pressures
trailer tire ratings
tv tire ratings and pressures
impact of inflation pressures on tires

and UNDERINFLATION as the primary cause of tire failures...

so search a little you will find HUGE amounts of info...
some is very useful
some not
most is user experience so take it as it's offered...
and unique to each trailer, tv and tire...

one should NOT inflate tv or trailer tires past the MAX cold inflation pressue listed on the sidewalls...

if your hitchsalesman was running lower pressures...
appropriate for the under loaded trailer
then yes adding 3-5lbs would improve mpg....

but IF the trailer tires are already inflated to 50psi for c rated or 65 psi for d rated marathons...

that's the limit.

all the above also applies to t.v. tires...

cheers
2air'

[moosetags]

We run at or 1-2# over the mfr recs on both the TT and the TV. We run 65-67# in the Airstream tires and 80# (rear) and 50# (front) in the Sub.

I don't know about increasing mpg; I just feel much safer with cooler running tires.

I don't bother with reducing TV inflation when not towing the TT. I did that for a while and didn't notice any appreciable ride quality increase. Therefore I quit bothering with it as it was a pain.

[davidz71]

I run my C rated Marathons a half pound over max (50.5) but do not put more than 72 psi in the rear tires of the truck (80 psi max D rated). It has worked fine.

[thecatsandi]

I run all tires at recomended pressure by the manufacture. That would be 45 on TV front, 70 Rear. 60 for the Trailer.

[LI Pets]

I run at the max air pressure with a load on my old truck this was a E-450 cube van 14,500 gvw .

But when empty or lite load the front end would steer funny, I'd drop it 10 lbs in the front and it it would feel great.

So I think you have to get to know the feel of the TV not just blindly set to the max.

I would not go over the max.

[steelbird312]

Isn't it amazing what we Airstreamers as well as other people do?
Like running pressures different from recommended.
Tire companies, especially the big ones, spend much time and effort producing tires, and then testing them for the tires optimum performance. They then publish these figures, and normally, the pressures go up as the weight does. However, remember that the sidewall gives a MAX pressure for MAX weight carrying capabilities. To get the best performance from our tires, we need to know the trailer weight and pressurize accordingly.
Then some guy installing hitches, or we, on a whim think we know better than do the engineers and their test results, decide we will run something different! The benefits of increased MPG (if it actually does increase it) are offset by earlier tire replacements due to worn center treads. Higher PSI also reduces the contact patch, traction capabilities (don't forget traction is needed for lateral stability as well as braking effectiveness) and ride softness (defined as stress on the trailer and its structural components). Tires have polymers and UV inhibitors added to the compounds to protect the tires, and they need flexing as well as heat to migrate through the tires. Yes, the least rolling resistance would be a steel-hard donut, but all the other qualities and performance needs our tires provide would be totally nill. Just my thoughts.
and on and on the debate goes...........

[silverback]

I have never pumped up the rear tires on the 2500 HD (TV) to 80 PSI which Chevy recommends. Even with the most gear I have ever crammed into the bed and the AS hitched up the rear suspension never dropped and the E range tires never squashed. I'd do 70 PSI max. My towing MPG doesn't change with tire PSI. Non-towing MPG does go up when the tires are inflated to my towing air pressure.
-KL