View Full Version : tires and psi

Jun. 23, 2010, 09:08 AM
Esp talking about in the heat:

tow vehicle -- tires inflated to door sticker recommendation or the max listed on the tire itself?

trailer -- tires inflated to trailer sticker recommendation or max listed on the tire itself?

Jun. 23, 2010, 09:19 AM
The general understanding is that autos and trucks are designed for certain tire pressures.

Varying much from them will change the handling characteristics.

Under steer, over steer, etc., either of which can put you in the woods.

So use the pressures called for on the door plate.

For a trailer, I use the tire spec.

It is conceivable that tires too hard could damage a poorly built trailer due to bounce and shock on a rough road, but I doubt it and it would take a lot of miles.

Most of the time, we have no idea what our trailer weight is. Under inflation for the weight is not good.

Watch the wear on the tread. More in the center than on the edges, tire too hard for the load. Excessive wear on the outside edges, tire under inflated for the load.


Jun. 23, 2010, 03:48 PM
I recommend using 90% of max inflation pressure for most loads (e.g., if you're at max load you want max inflation) unless it markedly differs from door plate. Most of the car recs are for ride, not max weight/performance.

Jun. 23, 2010, 06:56 PM
If I'm trailering with a load, I use the PSI the tires recommend.
If I'm coming home with an empty trailer, I usually let a few lbs of air out of the trailer so it doesn't "bounce".

Jun. 23, 2010, 09:11 PM
hmmm. My truck sticker said 65 for fronts and 80 for rears so that is what I did tonight. (the tires themselves say 80). So maybe I should put a little more in the fronts? I doubt I am at max load.

The trailer tires say 65 so I was going to plan on that re:cssutton's advice. Driving up to VA tomorrow AM.

Jun. 23, 2010, 11:40 PM
As I said in my earlier post.

Trucks and cars have suspensions designed around the PSI they recommend.

Varying the tire pressure from the PSI called for on the name plate will change the handling. You may not notice it under normal driving, but a bad rough spot in the road in a curve or an emergency might change the way the truck handles, to your detriment.

I have owned several F350's and have always run 65 PSI in front.

By the way, ordinary tire gauges are junk. You will see them vary 5 PSI.

Go to Sears or a good automotive store like NAPA and buy a digital tire gauge.

My dealer will not allow his employees to use the older style gauge.


Jun. 24, 2010, 05:54 AM
ok. I'll leave as is, thanks! oh yeah, digital tire gauges definitely. I bought a new one last night from Advance. I ain't playin' :)