.boB

On this board (and others) I constantly read statements like "I always run the maximum sidewall pressure".

Which is contrary to everything I know about tires. Since I race sports cars for a hobby, I know more about car and LT tires than the average person. For cars of all kinds, you need enough air pressure to maintain a flat contact patch. That means with a heavy load, you add air, and with a light load you release air. That transfers to pretty much all passenger vehicles - including a Ram pick up.

So I wondered if sports car tire technology transferred to trailer tires, at least to the basics, if not specifics.

So, I spent a couple of hours reading various sites that appeared to be reliable. Not "Bill Jones Tire Site". But places like Goodyear and Camping World. Places that have a vested interest in good information about the products they sell.

Everything I read said the same thing: Tire pressure depends on load carried.

So, for those in the "Max Pressure all the time" camp, why do you do that? Do you have any real data or referances to support this practice?

TexasCTD

boB.....it's my understanding that the max load capacity of a tire is when it is at it's max air pressure. Anything less, reduces it's capacity and will also build heat.


I run 16'' E rated LT tires on my Toyhauler now and just like the chinese maypops that were on it before....I keep the air pressure at max...80 PSI or close to it. My trailer's GVWR is 11,100lbs....and im sure im at that or close to it when I go camping....full of water, fuel station full, 3 or more ATVs, generator, all our gear etc. I just want to have as much capacity in my trailer tires as possible....which therefore means maxing out the air pressure.


Trailers are meant for hauling stuff.....so generally speaking...they are all about getting the load safely from point A to point B.

Sports car tires....handling, traction etc.....differ...because they have a different job to do. They are built for speed and cornering with a much lighter and lower slung load.

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MikeyB

Like TexasCTD mentioned, trailer tires is designed to carry a load from point A to B. Ride comfort or cornering ability is not in the equation. Only traction duty for the tire is in braking (trailer brakes) and water dispersal to prevent hydroplaning. Max pressure lessens the heat buildup in the tire.

We run our trailer tires at max pressure with the correct load rating to match or exceed the maximum carrying weight of the trailer. It's one less thing to worry about and it's a peace of mind.

MikeyB

Totallyrad

I run 16's on my GN equipment trailer. I'm always between 75 and 80 psi because I base the tire pressure on the tire wear. A heavier load needs more air to wear the tires evenly, just like on the tow vehicle. On my truck, I'm 75 front and 30 rear.

Jeff in TD

Some trailer tire makers recommend running at max psi.

http://www.carlisletire.com/product_...ire_poster.pdf

I had one blow on my 5th wheel, and started running them at max psi and haven't lost another one since.

GAmes

I run my trailer tires at max also. Because of the floor plan on my 5er the left side tires carry more weight than the right and I've read that you shouldn't carry different pressures on the same axle. They run cooler, and face it, usually the tread isn't anywhere close to worn out when the tires reach the 5-7 year end of life.

st.rodder2

I found that running at max pressure will also help reduce any sway that you get.

dott

When you mention cornering on a sports car, what would you call it when you have to make a tight turn with your tandem axle trailer? Both tires are working in different directions in a cornering situation with (I suspect) a lot more force on them.

TexasCTD

Oh I have no doubt that when you take a sharp corner with a trailer it shifts the weight to the outside wheels. That is all the more reason to keep the tires at max pressure.

Hopefully with my trailer in tow....i'll be taking said corner a little slower than in a sports car however...

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Wild4kst8

i'm of the school of why not? if you were to have an issue, i'm guessing that the first thing someone will ask is what pressure are/were you running... i try to run as close to max as possible (plus or minus due to weather conditions)

Busboy

I understand that the tire is rated to carry a certain load at a certain pressure, reduce the pressure and you reduce the load carry capacity of that tire. 3042lbs at 80 psi reduced to 50 psi gives 3042 divide by 80 multiply by 50 = ONLY 1901 lbs. That's why most people run their tires at MAX inflation.
If towing an empty flatdeck you could reduce the pressure but would have to increase when loaded. An RV stays around the same weight all the time.

ripping r

I run max pressure on the ram for the best mpg. it rides a little harsh but i dont care. and my trailers at max for all the above. and it pulls better. since i have less rolling resistance.

Mega Ram

I too am of the opinion that you should only inflate your tires to what the manufacturer specified. If you over inflate you may run cooler, however your contact patch for stability (i.e. floating or bouncing and braking )is simply inadequate.
If all goes well the loss of 10 or 15% of performance will go unnoticed. It’s only when the hits the fan like going down a hill in the rain and you jump on the brakes when you really need 100% performance.
I race a motorcycle and have a race car. I can tell you that both under or over inflated tires are very dangerous. You may not feel the loss of stability in your trailer, but you may have seen other peoples trailers bouncing down the highway.

.boB

That is definatly a bad idea. Performance wise, you're losing your contact patch. Your braking and cornering effectivness is significantly reduced. That's a bad thing. It will really be noticable next time you perform an emergency manouver.

Money wise, you're being penny wise and pound foolish. You will get slightly better gas mileage. But, you'll only get 1/2 - 2/3 tire life. What little you save in fuel will be grossly overshadowed by rubber expense.

Mega Ram

ditto