TV tire pressure (mainly the front tires)

CapriRacer wrote:
The one thing that hasn't been mentioned is that every vehicle has a vehicle tire placard that lists the original tire size and the proper pressure for that size. If you are using the tire size listed there, then that pressure has been tested by the vehicle manufacturer.

Personally, I think that is the correct pressure to use - unless there is a specific reason to deviate from that.

That's true and usually good advice. However there are other factors. The tires themselves for example. A deviation from OEM tires may not give you the same results, even at the same tire size. I put Firestone Destination LE tires on my Trailblazer. The first thing I noticed was that my mileage dropped, until I put 3 extra PSI in them. OEM pressure in the door is 30 front, 35 rear. With our new HTT I have to run 40psi in the rear and 35 in front. It made a huge difference in the towing experience and in towing mileage.

X2

My door jam says 55front and 80rear. That is what I run when towing. I will go to 55rear when not towing so the ride is not so harsh.

Cale

The one thing that hasn't been mentioned is that every vehicle has a vehicle tire placard that lists the original tire size and the proper pressure for that size. If you are using the tire size listed there, then that pressure has been tested by the vehicle manufacturer.

Personally, I think that is the correct pressure to use - unless there is a specific reason to deviate from that.

The problem with blanket statements is the the meaning gets lost and then it gets applied wrong or out of context.

Tires have load ratings and a "must" is the tire must have adequate air pressure to carry the load. This one if pretty cut and dried.

Now the shades of gray and this gets more complex as newer vehicles have changed to larger wheels and lower profile tires. When towing the tire stiffness can make or break a stable rig. P tires and even LT tires can have very flexible side walls. They ride nicer non towing and they help cushion the ride while holding the weight.

However, cushy tires and trying to control a TT can have very opposite results. They are saying to air up your tires is meant to stiffen the tire. You have to have the pressure to handle the load but you also need the stiffness to help control the TT.

There are a number of factors that affect how much extra pressure is needed all the way up to max cold pressure. And in some cases, even max pressure is not enough. Truck wheelbase, truck type of suspension, how loaded that suspension is and even more so, brand/type of tire to name a few.

If the front tires are not stiff enough, as a sway force hits the trailer, the truck tires have to resit it. If they flex very little in the side wall, the truck stays stable left to right. If the tire is soggy, the front of the truck will fell like it is shifting left to right, sometimes it feels like the back of the truck is shifting but it can be the front.

They do not create a stiffness rating for tire side walls so you sort of buying blind. Some have P tires that do very well while others can't control much no matter what they do. Even some LT tires are like this. The max pressure guide is a way to help create that stiffness. How much is an experiment. Start in 5 psi jumps above door sicker pressures all the way to max. In the LT tire you can approach a hard bounce where the truck little feels like it just jumped left or right after a bump. That is too stiff back off 5 psi and try again. A gasser 3/4 ton truck might have the hard bounce issue on the front where the same truck with a diesel up front won't. Same tire but different loading.

I have found the newer, large rim/smaller profile tire if a lot stiffer from the get go. Since there is less rubber profile the tries flexes less. They do ride harder but flex less. It's a trade off.

So while from a load stand point you may not need extra pressure, you may from a stiffness stand point.

Good luck and hope this helps

John

I use the tire pressure charts for the load each wheel carries plus 5 psi for luck.

Note tires on any one axle should be inflated to the highest needed for the two tire weights.

Personally I always make sure my front TV tires INCREASE slightly in weight with TT attached. After all they do all the steering, and most of the braking. I want front tires firmly planted, and tire to road contact patch at maximum. Worked great for over 200,000 miles so far.

A P265/70-17 tire at 35 psi or 44 psi P tire is a very soft tire at those pressures. They need all the help possible when towing/hauling.

A LT265/70-17 C or D or a E tire at 50 psi or 65 psi or 80 psi is a very stiff tire.

When towing with the wifes 1500 crew cab chevy 4x4 with the size above P tires I find max 44 psi works best when towing a trailer even though the tire placard says 35 psi.

There is no one size fits all...even socks...

Depends...

Tire PSI is more than carry weight but the main (IMHO) thing is to keep the
tire shape during all maneuvers

Also depends on the class/model/size vs vehicle spec/wheel spec/etc with the
biggie how & where you drive vs the loading for that setup

For my GMT400 Suburban, depends on which set of tires and where I'm at

For my off road setup....it is OEM steel wheels and LT235/85R16E's. On pavement
air them up to 80PSI both empty and hauling/towing

Once off road it ranges from 15PSI up to 50PSI, but go no faster than 25MPH when
at 50PSI and crawling when at 15PSI

Pavement setup is LT265/75R16E's on alloy 16x10. If fooling around empty, the
rears are about 60PSI and the fronts are 50PSI-60PSI. If towing and can get
even drop or get non-loaded weight back on the front axle (don't weigh it and
just measure and/or eyeball from experience) run 60PSI-70PSI front and 80PSI
rear no matter how much (loaded hauling or towing heavy)

If you got P rated tires on your Tundra, go max pressure on the front. They are soft enough.
If you have some good LT tires, then match the weight to the pressure.
Not really a set formula, but in general if you're adding weight toa particular axle, air up as necessary. If you're unloading the front axle, then keep it at the psi you use when empty.
Example.
I run (in the summer) 60psi front and 45-50psi rear in my Doage 2500 diesel. Loaded up with the camper and a trailer in tow, I'm actually unloading the front (Cummins makes good ballast though!)since the camper c of g is just behind the rear axle centerline combined with tongue weight.
I knocked the fronts down to 55 psi to soften the ride a bit without too much tire flex and ran 80psi in back for obvious reasons.

I go with max pressure. It's easy and there's no thinking.

If I was going to think about it, I'd go with my scaled weight, pad it slightly and go with the load table.