Mixed Tire PSIs

[bwessale]

I have a double-axle trailer and replaced the rear axle tires. I now have Carlisle RH on the front axle and Carlisle HD on the rear axle. The RH has a recommended pressure of 65 PSI and the HD has a recommended pressure of 90 PSI.

Should I run the two sets of tires at their recommended pressure, or should I run the rear tires at 65 PSI to match the front tires?

My concern is that if the back tires have 90 PSI and the front tires have 65 PSI, won't the back tires end up carrying 30%-50% more load than the front tires?

And if they do, does that matter?

I called Carlisle tire, and they recommended running each set of tires at their recommended PSI until I make the permanent fix and replace the front axles RHs with HDs.

Thanks,

Bill

[wa8yxm]

How did you get the "Recommended Pressure"
Method 1: Sticker inside trailer
Method 2: Molded into sidewall of tire
Proper method: Scale the beast and use the chart from the tire maker

The pressure on the side wall is at the end of a sentence.. READ THE ENTIRE SENTENCE and you will understand. If you switch from a low load range tire to a higher one,,, You may see a higher pressure on the sidewall

BUT unless the load also increased, the recommended pressure likely will not have changed.

[AniJet]

bwessale wrote:
...........At least the tires are both radial, from Carlisle, and have the same tread pattern.

Thanks everybody!

If they are also the same size and, the 65 psi tires are rated to carry the weight, run the fronts at 65 psi and backs at 75 and you should be fine. The traction and stability will be very close.

Different size, radial mixed with bias, and in some cases, different manufacture would be a no go.

[JohnG3]

To add an additional layer to this discussion, there is an RV mobile weighing fellow who uses computer flat plates to weigh each tire. The RV needs to be loaded as it will generally be driven. He then recommends the tire pressure for each wheel.

Full disclosure I don't buy into that sales pitch. I can see a small difference in weight from left to right (just the sofa on the right side VS kitchen with refrig/water heater/pots and pans/etc on the left side. I don't see any difference front/rear on the same side. His rational is that the proper PSI will extend tire life.

[Sport45]

If you lock up any trailer wheels when braking on dry pavement your controller is set too aggressive. I wouldn't loose any sleep over having different rated tires on the two axles of a trailer as long as the lesser rated tire will carry the load. I would definitely match tires side to side on each axle and my preference is to have the newer tires on the front axle.

[bwessale]

Thanks for the quick responses!

Overall, it sounds like I might be OK until I brake hard, but I really should replace the other two tires on the front axle so that I have four identical tires.

We have a short trip (200 miles each way on interstate) planned next week, so I am going to risk it and tow it with the two different load rating tires (and hence PSI) - to avoid the hassle of changing the tires and $275. Ben Franklin's words are echoing in my head: "Pennywise and pound foolish". At least the tires are both radial, from Carlisle, and have the same tread pattern.

Thanks everybody!

[JIMNLIN]

At one time Carlisle website recommended not mixing load ranges/tire sizes or tread types for tires on a trailers.
They came out with a new different website when the RH tire hit the street.

Then just a few months back Carlisle tire and rubber became Carlstar group along with the new HD with another new web change.

Now for some reason I can't get any Carlisle or Carlstar group websites to come up other than their store.
Anyone have a link to Carlisle warranty/FAQ/etc...other than their trailer tire store ??

[tinner12002]

I think if the OP weighs his trailer and knows what weight he has on the axles could make a diff. Some manuf say you can run lesser pressure based on weight their carrying, not sure about Carlisle. If the OP has a TPMS system he could play with the pressures some based on his tire temps. Personally I would have put the same tires all the way around even if it meant biting the bullet so to speak.

[ken56]

Just put the HD's load D1 on my trailer and the sidewall says 65psi....Load E1 is 80psi and load F is 95 according to the web site.

[colliehauler]

Lots of vehicles recommend different air pressure in the front vs the back tires, my Excursion is one of them. Would do what tire mfg recommended until you can replace the front two.

[DrewE]

ScottG wrote:

Boon Docker wrote:

I did think about it and a panic stop is not going to do what you say if the tires are both radial and the same size.

Radial is only the half of it. Tire tread and especially, air pressure play a big role in how a tire grips the road.
Ever have one low tire and not realize it only to slip sideways unexpectedly? If not then you just havent had the experience but it does happen. (Happen to me twice)

I would think (and hope) that the poster is thinking of keeping the tires of the same type paired across axles, not having one side at one pressure and the other at the other pressure. That should even out any tendency to go sideways unexpectedly, or so I think.

My motorhome has 65 psi in the front tires and 80 psi in the back tires, as appropriate for the loading and recommended by the maker, and it doesn't have a tendency to suddenly slip sideways or otherwise have poor handling.

[Boon_Docker]

With a vehicle, yes. With a tandem axle trailer, I've never had that experience.

[ScottG]

Boon Docker wrote:

donn0128 wrote:

Boon Docker wrote:

ScottG wrote:

donn0128 wrote:
No matter what IMHO you asking for trouble. Before towing at hiway speeds you really need all 4 tires the same size/rating.

X2.
One good panic brake and your going to be all over the road.

Why, what would cause it to do that?

OH gad, think for a minute.
Mismatched tires can cause all sorts of handling issues, from wonder/sway to improper loading. If you have ever had a mismatched set of tires on a car you would understand how squirlly things can become. Add a sudden panic situation and you can find yourself in real trouble in a hurry.

I did think about it and a panic stop is not going to do what you say if the tires are both radial and the same size.

Radial is only the half of it. Tire tread and especially, air pressure play a big role in how a tire grips the road.
Ever have one low tire and not realize it only to slip sideways unexpectedly? If not then you just havent had the experience but it does happen. (Happen to me twice)

[Boon_Docker]

donn0128 wrote:

Boon Docker wrote:

ScottG wrote:

donn0128 wrote:
No matter what IMHO you asking for trouble. Before towing at hiway speeds you really need all 4 tires the same size/rating.

X2.
One good panic brake and your going to be all over the road.

Why, what would cause it to do that?

OH gad, think for a minute.
Mismatched tires can cause all sorts of handling issues, from wonder/sway to improper loading. If you have ever had a mismatched set of tires on a car you would understand how squirlly things can become. Add a sudden panic situation and you can find yourself in real trouble in a hurry.

I did think about it and a panic stop is not going to do what you say if the tires are both radial and the same size.

[jwandvassie]

goducks10 wrote:
I highly doubt that trailer will know it has different tires on. All those tires are doing is carrying the trailer and following the truck. Unlike a car or truck where they're required to stop, turn and accelerate. I would air them as per the sidewall. If you were mixing different size tires and load ratings then, yes you could encounter an issue.
The tires are going to carry the same load regardless of how much air you have in them. Think about it for a minute. If you let the air out of the front or the back tires, will the axle load weigh less? No. The weight on the tires will remain the same. The only thing that's changed is that the rear tires are more capable of carrying the same load as before.

This is the correct answer.