Airing down the trailer tires?

[SimRacer]

OP, might I suggest searching for and reading posts/blog from Roger Marble (Tireman9). HE is the expert on tires !
Minimum does not equal best or safest. Safe travels !!

[RVPioneer]

Originally Posted by Dave Pelletier

sort of; you can deduct the tongue weight which at a low 10% puts the 21RBS at 30lbs.....again, not that I'd go that low


Dave

That would put you at 1609 per tire, which rounds up to 35psi.

[Dave Pelletier]

Originally Posted by RVPioneer

That would put you at 1609 per tire, which rounds up to 35psi.

😆 well since the tongue weight would actually be well over 10%, we can forget about the 9 lbs and go with 30psi.....but again, I'll likely run at least 50 anyhow.

Dave

[JIMNLIN]

This from Goodyear tires "weighing tires on rvs" pretty much sums it up what Goodyear "SAYS" on the tire/trailer/psi subject. Goodyear is assuming the tire on a trailer are fitted per FMVSS 571 safety requirements for tires/wheels and axles.

SpecialConsiderations
Unless trying to resolve poor ride quality problems with an RV trailer, it is recommended that trailer tires be inflated to the pressure indicated on the sidewall of the tire. Trailer tires experience significant lateral (side-to-side) loads due to vehicle sway from uneven roads or passing vehicles. Using the inflation pressure engraved on the sidewall will provide optimum load carrying capacity and minimize heat build-up.

Now if a newb has over tired the trailer, say 25 + percent above axle/wheel load requirements then max pressures won't work.

[RVPioneer]

Originally Posted by JIMNLIN

This from Goodyear tires "weighing tires on rvs" pretty much sums it up what Goodyear "SAYS" on the tire/trailer/psi subject. Goodyear is assuming the tire on a trailer are fitted per FMVSS 571 safety requirements for tires/wheels and axles.



Now if a newb has over tired the trailer, say 25 + percent above axle/wheel load requirements then max pressures won't work.

Agree that max sidewall pressure is a standard recommendation for ST tires. ORV literature shows ST235/80/16E as the factory tires on the OP’s trailer. The OP has stated that ORV recommends 70psi. That pressure would support ~6200lbs per axle. Axle ratings are 5200lbs each, GVWR just under 10K.

My hat is off to ORV for equipping their trailers with tires that are capable of supporting more than the GVWR of the trailer. More often than not, trailers are equipped with tires that can barely support the weight at max pressure. Personally, I wouldn’t consider the trailer over tired and if it were mine, I’d be more likely to run them at 70psi as opposed to 50psi.

[Dave Pelletier]

Originally Posted by RVPioneer

Agree that max sidewall pressure is a standard recommendation for ST tires. ORV literature shows ST235/80/16E as the factory tires on the OP’s trailer. The OP has stated that ORV recommends 70psi. That pressure would support ~6200lbs per axle. Axle ratings are 5200lbs each, GVWR just under 10K.

My hat is off to ORV for equipping their trailers with tires that are capable of supporting more than the GVWR of the trailer. More often than not, trailers are equipped with tires that can barely support the weight at max pressure. Personally, I wouldn’t consider the trailer over tired and if it were mine, I’d be more likely to run them at 70psi as opposed to 50psi.

Yep, the tires are just another reason why ORV came out ahead on my purchase decision. I'd suggest that ORV's are indeed "over-tired" which I think is a good thing. The OP's trailer with a max GVWR of 9995 and using a low tongue weight of 10% shows that his tires can support his max load of 2248lbs/tire using as little as 40 PSI (good for 2270lbs) BUT I'd never run them that low;

When the pressure is too low;
- increased heat
- increased wear on the tire edges
- more sidewall deflection, less stability

when the pressure is too high;
- premature wear on the tire center
- less traction/grip
- harsher ride.

Now, a harsher ride isn't an issue due to no occupants but it can increase wear/damage on a rough/dirt road. Certainly it's better to have too much pressure than pressures that are too low as the consequences are far more severe......when in doubt, air up.....even to max inflation pressure if you must. The better answer is probably to check the chart to ensure you have AT LEAST that much pressure and to do a loaded chalk test to optimize traction and tire wear. Personally, I am comfortable trying my trailer at a pressure between 60PSI and the max 80psi noted on my sidewall.

As far as the OP's orginal question, there should be no concern with running as low as 40 PSI for temporary offroad, low speed towing if he want's to reduce wear/damage to the trailer in rough conditions.....I'd air up before hitting the highway......how much to air up, I'll leave to you after digesting this thread! :-)

Happy Holidays and Merry Christmas everyone; may 2021 be a great year with fabulous camping!

Cheers,
Dave

[Gammel]

Thanks to all! I think my minimum will be 50. Now who’s gonna remind me to air back up? On second thought I think I’ll leave ‘em at 70 and do a high speed run on some good washboards regularly to convince any recently boarded rodents that they picked the wrong trailer to invade.

Merry Christmas and a Happier New Year!

[xc-mark]

Originally Posted by Dave Pelletier

Yep, the tires are just another reason why ORV came out ahead on my purchase decision. I'd suggest that ORV's are indeed "over-tired" which I think is a good thing. The OP's trailer with a max GVWR of 9995 and using a low tongue weight of 10% shows that his tires can support his max load of 2248lbs/tire using as little as 40 PSI (good for 2270lbs) BUT I'd never run them that low;

When the pressure is too low;
- increased heat
- increased wear on the tire edges
- more sidewall deflection, less stability

when the pressure is too high;
- premature wear on the tire center
- less traction/grip
- harsher ride.

Now, a harsher ride isn't an issue due to no occupants but it can increase wear/damage on a rough/dirt road. Certainly it's better to have too much pressure than pressures that are too low as the consequences are far more severe......when in doubt, air up.....even to max inflation pressure if you must. The better answer is probably to check the chart to ensure you have AT LEAST that much pressure and to do a loaded chalk test to optimize traction and tire wear. Personally, I am comfortable trying my trailer at a pressure between 60PSI and the max 80psi noted on my sidewall.

As far as the OP's orginal question, there should be no concern with running as low as 40 PSI for temporary offroad, low speed towing if he want's to reduce wear/damage to the trailer in rough conditions.....I'd air up before hitting the highway......how much to air up, I'll leave to you after digesting this thread! :-)

Happy Holidays and Merry Christmas everyone; may 2021 be a great year with fabulous camping!

Cheers,
Dave

I have to agree with Dave on this, running 30 PSI on a trailer or car tire is just asking for sway issues. True max side wall tire pressure may be a rough ride and there is some room for improvement but I would never run more then a 20 lb reduction of tire pressure . I would suggest you look into a center trunnion that can help mitigate the impacts of holes. The Morride RE3000 or 4000 is very good . I have personally used the Dexter part that has a rubber block in the middle , it was noticeable better after. trailer shocks is also a great upgrade. the LCI CenterPoint that has a airbag is very good to smooth out the ride but these should be a starting point to keep your trailer from falling apart not dropping the tire pressure to a unsafe level like 30 psi.

[tuffr2]

How fast are you towing on the bad road. I believe airing down is an ok idea. That is if you are towing at 25mph on this bad road. If still towing at 70mph then no? Don't air down as too much heat might desinagreate the tire.

[Dave Pelletier]

Originally Posted by tuffr2

How fast are you towing on the bad road. I believe airing down is an ok idea. That is if you are towing at 25mph on this bad road. If still towing at 70mph then no? Don't air down as too much heat might desinagreate the tire.

Agreed; I'm assuming he's not going 70mph on these rough dirt roads with washboard.

Dave

[Gammel]

I ALWAYS keep it under 90 on the dirt!

I can't imagine towing a trailer on anything but the best dirt roads at more than 25 or 30. On even lite washboards 15-20 would be about my max.

[tileguy]

I believe the problem if you air down on a gravel or dirt road with rocks or pot holes even going slow wouldn't be the heat or bad wear but a pinch flat or a blown side wall from a rock or the pot holes due to the wieght of the rv. A pinch flat happened to me a few years back, hit a pot hole just right with a low tire and loaded you hauler and instant pinch flat. For those that dont know of a pinch flat, it's when your low tire gets pinched from the rim due to the weight of the vehicle and a rock or pot hole. So I would recommend always run your tire pressure as needed for your wieght

[NevadaNick]

I live and play where we travel gravel roads for miles. When i had my TT i ran E rated tires in place of the D rated and never ran 80psi ever, same goes for my enclosed trailer, replaced D with E and have always ran 70psi on it and the TT have been down the same dirt roads at 50-60 mph. One reason i never run full pressure is to prevent rock punctures but i have also never aired down below what i always run. The same trailers with 70psi have been pulled 75-80mph on the highway (legal speed limit) and other than one small cargo trailer that i hit something with on the highway late at night have never had tire issues. If the road is wash board speed will smooth it out some, but you have to remain in control. I realized that when i travel these roads that there will usually be a drawer or something that opened and its just a fact of life of where i travel. I ran my DP motorhomes down these same roads the same speeds with the same outcome. Like it or not conditions determine the outcome most times.

[xrated]

Here is something to think about, and seriously consider BEFORE deciding to "air down" tires. This is a quote from USTMA....United State Tire Manufactures Association.....

"The USTMA says a tire found to be 20% below it's recommended cold inflation pressure is in a run flat condition."


So if you do the math on a tire that has a sidewall psi rating of 80, that tire would be considered to be in a "run flat condition" if the pressure was 64 psi or below! So do you really want to run your tires at reduced pressures.