Proper PSI For Trailer Tires?

[Tumbleweed13]

I'm curious as to what you consider the correct psi, to put into your trailer tires? I have a toy hauler, 28' twin axle. Fully loaded i'm 15 - 16K lbs. The max rating on the tires, is stated at 80psi. I've always pumped them up, to 75psi. Giving me a bit of room for pressure increase, due to heat.

What do you guys think?

I have a buddy, that has a very similar set up, and he only runs 50psi. His tires have the same max psi as mine. Is this ok too?

That are your thoughts on this?

Thanks, Joe

[JIMNLIN]

Snipped from Tireman9 rvtiresafety.com blog;

*When not driving in a straight line there are special side loads on multi-axle trailers because the tires are fighting each other because they are not "pointed" to the center of the radius of the turn. These loads cause interior structural tearing. Sometimes 24% higher loads than those seen in tires on non-trailer application. Initially tearing is at the microscopic level but with time and repeated cycles these forces grow which can lead to small cracks at the belt edges as seen here at the arrows.*
and
*You can lower these forces by either decreasing the load 24% on the tire (probably not something you want to do or may not be able to do) or you can increase the inflation to stiffen the structure and decrease the slip-angle. In this case you could increase the tire inflation from the minimum inflation needed for the static load to the inflation associated with the max tire load as molded on the tire sidewall.*

Also add the fact ...many trailers can weigh more on one side than the other. Using a pressures from a minimum pressure chart may cause the tire(s) on the heavy side to run over loaded.

A severally over tired trailer has its own problems with the best psi for the good of the tire.

[TexasChaps]

mike-s wrote:

theoldwizard1 wrote:

TexasChaps wrote:
I run at max cold pressure as stated on the sidewall.. never had a problem.. ever..

Correct !

Maybe, if the original spec tires are installed, and the camper is loaded near its load capacity. If the max load calls for a LR B tire (35 PSI), but LR C (60 PSI) tires were installed, inflating to the max is probably not the thing to do. It will cause a harsher ride. A LR C tire at 40-50 PSI can provide a compromise between more load capability (margin/safety/longevity/reliability, which can be a separate argument) and an overly harsh ride.

Car and truck tires are frequently specified at less than their max load pressure, simply because the max load isn't needed.

And, some TTs may be similar - the tire/pressure label is what to go by, not what's marked on the tire sidewall.

quite right, but you will find that most OEM specified trailer tires are marginal at best.. hence all the talk of upgrading to larger sizes and or LT tires.. my TT for example has the same pressure on the sticker as the tire.. so on stock tires I would prefer a "harsher" ride than under inflated tires..

[goducks10]

I've always ran my TT tires to the max psi on the tire which was the same as the TT's tire sticker. I now had E instead of D rated tires on. I run them lower than the max psi of 80 because they have a higher weight rating. You need to run the tire at whatever psi is applicable to it's load.

[mowermech]

You can always try the "chalk test" to find the CORRECT tire inflation.
Make a chalk mark or two (or more) across the tread of the tire. Drive a few yards on a hard surface, then look at the chalk mark(s).
If the chalk mark(s) are worn off evenly across the tread, the inflation is just right for the present load.
If the chalk mark(s) are worn only on the sides of the tread, the tires are under-inflated for the load. Add air.
If the chalk mark(s) are worn only in the center of the tread, the tires are over-inflated. Remove air.
For best traction in braking and turns, the contact patch between the tire and road must be as large as possible. Over or under inflation reduces the size of that contact patch, and wears the tread unevenly.

[ReneeG]

mike-s wrote:
Tire and loading sticker on the left side, in front near the bottom.

PSI is cold pressure, if it calls for 80 PSI, put 80 PSI in when cold. 75 PSI would be underinflated. The given pressures already take into account any pressure increase from heat.

Exactly and also the advice per the tire shop.

[NHIrish]

You can weigh your trailer...all wheels...and get the answer needed to use a tire pressure chart to potentially soften the ride of the tires by using a reduced pressure....or you can get the maximum load rating of the tire by using the cold psi on the sidewall of the tire.

I'm a simple guy and want the max load rating on a trailer that is subjected to road forces, sway etc....but that's me. For my money, it does not make sense to accept a reduced load rating to soften the ride on a trailer. And yes...the sticker on the side of the trailer will tell you the pressure for the tires your rig came with...

Picking a number out of the sky or not checking the tires is not in your best interest...

[RedRocket204]

Wild Card wrote:
For example my dually rears are rated 65psig...and thats what is on the door sticker. If i am unloaded its ridiculous tonrun max psi. Sometimes too much air is a bad thing

And what you are addressing is for a motor vehicle... not what the OP asked about as the OP's question was concerning trailer tires.

[tinner12002]

Wild Card wrote:
For example my dually rears are rated 65psig...and thats what is on the door sticker. If i am unloaded its ridiculous tonrun max psi. Sometimes too much air is a bad thing

That's funny because my dually tires are rated at 80psi just as the fronts. Door sticker says to run 65psi for max load but other than ride quality if I had 4-5K on my pin I do think I would bump it up above 65psi. Just my opinion. As for the OPs question, I run anywhere between 75-80psi in my trailer tires. Tires are rated at 80psi at max load so that's what I start out on trips with, if it drops to 75psi overnite I don't worry as the psi comes up when traveling and as outside temps come up.

[mike-s]

theoldwizard1 wrote:

TexasChaps wrote:
I run at max cold pressure as stated on the sidewall.. never had a problem.. ever..

Correct !

Maybe, if the original spec tires are installed, and the camper is loaded near its load capacity. If the max load calls for a LR B tire (35 PSI), but LR C (60 PSI) tires were installed, inflating to the max is probably not the thing to do. It will cause a harsher ride. A LR C tire at 40-50 PSI can provide a compromise between more load capability (margin/safety/longevity/reliability, which can be a separate argument) and an overly harsh ride.

Car and truck tires are frequently specified at less than their max load pressure, simply because the max load isn't needed.

And, some TTs may be similar - the tire/pressure label is what to go by, not what's marked on the tire sidewall.

[Wild_Card]

For example my dually rears are rated 65psig...and thats what is on the door sticker. If i am unloaded its ridiculous tonrun max psi. Sometimes too much air is a bad thing

[Wild_Card]

Max psi on sidewall is for max weight rating.
Every tire mfg has psi to load chart

[BarneyS]

TexasChaps wrote:


I run at max cold pressure as stated on the sidewall.. never had a problem.. ever..

Ditto here also!
Barney

[ScottG]

theoldwizard1 wrote:

TexasChaps wrote:
I run at max cold pressure as stated on the sidewall.. never had a problem.. ever..

Correct !

Ditto

[theoldwizard1]

TexasChaps wrote:
I run at max cold pressure as stated on the sidewall.. never had a problem.. ever..

Correct !

[TexasChaps]

Tumbleweed13 wrote:
I'm curious as to what you consider the correct psi, to put into your trailer tires? I have a toy hauler, 28' twin axle. Fully loaded i'm 15 - 16K lbs. The max rating on the tires, is stated at 80psi. I've always pumped them up, to 75psi. Giving me a bit of room for pressure increase, due to heat.

What do you guys think?

I have a buddy, that has a very similar set up, and he only runs 50psi. His tires have the same max psi as mine. Is this ok too?

That are your thoughts on this?

Thanks, Joe

I run at max cold pressure as stated on the sidewall.. never had a problem.. ever..