Load range E--ST Tire

[Bob2952]

Just bought my first RV. It's used with 2yr old tires.
I'm planning a long trip and all the talk about the tires is confusing. My travel trailer is 28ft with dry weight of 6000 lbs.
The tires say maximum cold tire pressure is 80 psi.

Because the tires are ST are they safe to use with 80psi and an average speed of 60mph? Everybody has opinions but I would like to know if anybody has the same tires with good results?
Thank you

[JIMNLIN]

shelbyfv wrote:
FWIW, Goodyear now has a load/inflation chart for the Endurance ST.https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

Goodyear also says in their rvtires website "weighing your rv"...

*Special Considerations*
***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.***

clicky link

Good advise as the first part covers those that over tire their trailer above recommendations.
The last mentions side to side loading. We see that out here in high wind areas and 40 mph side winds.
I've seen my 16" LT E tires on service trailers (3042 lbs with 6k axles) run 92-94 psi all day long in 110 degree outside temps.

[shelbyfv]

FWIW, Goodyear now has a load/inflation chart for the Endurance ST.https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

[NamMedevac_70]

For a great many years in summer high heat I always ran my heavily loaded TT tires at the full recommended max pressure with no blow outs or flats or any problems and no bouncing trailer. Some folks like extra tho. It keeps them busy.

Cheers to good camping and fishing

[Ponderosa]

Don't run an ST at anything less than the rated load pressure (80 psi in the case of and E tire). There is not a load based adjustment for ST tires.

So yes, pump em up to 80, cold, meaning before you take off, and roll. There's a couple variables like how old they are and is the rubber in good shape (no hairline cracks in the tread grooves, weather checking on the sidewalls. But otherwise...

[Grit_dog]

^Great explanation.
And I’ll add, you actually have about another 200-250lbs reserve or less load per tire than the above explanation, since reasonably, about 800- 1000lbs of the trailer weight is on the tongue and not the axles.

[JRscooby]

Bob2952 wrote:
Not sure how I put this in Class A motor homes? My first post.
Appreciate all the info. To modify my question (my travel trailer is 6000lbs dry. With added cargo 2000lbs it has max weight 8000lbs) my tires are ST225/75R15 load range E speed rating 75mph. Load 2830lbs single/2470lbs dual.
If I put 70-80 psi in my tires and average 60mph am I good to go 1000 miles?

Why would you want to run less than the Max pressure on a trailer tire? Do you want more sidewall flex creating heat? That heat is what causes most tires to blow.

[CapriRacer]

Bob2952 wrote:
Not sure how I put this in Class A motor homes? My first post.
Appreciate all the info. To modify my question (my travel trailer is 6000lbs dry. With added cargo 2000lbs it has max weight 8000lbs) my tires are ST225/75R15 load range E speed rating 75mph. Load 2830lbs single/2470lbs dual.
If I put 70-80 psi in my tires and average 60mph am I good to go 1000 miles?

OK, doing the math:

If 4 tires are 8000#, then 1 tire is 2000#, but if we account for front to rear and side to side variation (12%) we get 2240#. An ST225/75R15 Load Range E has a load carrying capacity of 2830# at 80 psi and at 70 psi, 2620#, so at 70 psi, the reserve capacity is 17%.

That sounds good to me. But here's a way to check it. It's called Pressure Buildup.

Measure the pressure and the ambient temperature right before you start out.

An hour later check the pressures and temp again!

You don't want any more than a 10% buildup excluding ambient temperature effects (2% for every 10°F)

[Bob2952]

Not sure how I put this in Class A motor homes? My first post.
Appreciate all the info. To modify my question (my travel trailer is 6000lbs dry. With added cargo 2000lbs it has max weight 8000lbs) my tires are ST225/75R15 load range E speed rating 75mph. Load 2830lbs single/2470lbs dual.
If I put 70-80 psi in my tires and average 60mph am I good to go 1000 miles?

[theoldwizard1]

Bob2952 wrote:

The tires say maximum cold tire pressure is 80 psi.

Because the tires are ST are they safe to use with 80psi and an average speed of 60mph?

ST tires (and LT tires when used on a trailer) are design and safe to run at their maximum pressure. There are speed rating for all tires, (not sure if it is on the sidewall), but I do know that unless the tire is specifically stamped "not safe for highway use", it can be run at legal highway speeds all day long !

Ply rating and letter ratings on tires are "old school". All tires sold in the US MUST have their load ratings, stated in pounds, embossed on the sidewall.

[Ponderosa]

ST tires used to be rated for only 65 mph continuous use. Today, they come in various speed ratings given by a letter code on the side wall like regular tires. L is 75. M is 81 and N 87. You don't see a lot of N's.

[NamMedevac_70]

For many years of travel in high summer heat in the western USA that began in Texas I have had excellent results with new ST Maxxis and Goodyear trailer tires on my 28 foot 5000lb TT with no flats or blow outs and only one slow valve stem leak. My TT was always heavily loaded and drove at speeds between 55 and 70MPH.

I always use LT Goodyear tires on my Dodge Ram trucks that were 1500 and 2500 V10 series. Very great experiences.

Cheers to the big wizard.

[way2roll]

The first thing I would do on any TT or FW is inspect the tires. If they are a cheap brand ST type tire I would replace them with a brand name LT tire. We had 2 blowouts on cheap OEM tires when we had our FW. The blowouts were within 5 miles of each other and did significant damage to the FW. They put the cheapest tires they can on TT's and FW's and they are a disaster waiting to happen. The term tire bomb comes up quite a bit on various RV forums. Now if the previous owner replaced the tires then that could mitigate the issue.

[MFL]

ScottG wrote:

Bob2952 wrote:

Because the tires are ST are they safe to use with 80psi and an average speed of 60mph?
Thank you

Yes.

Agree, yes, but to last part of OPs question, many have run E-rated ST tires with good success, and some, not so good. Reason...all ST tires are not created equal, and by design, some more dependable than others. What brand tires are they? If just 2 yo, could be a quality, newer, improved ST tire, with higher speed rating.

Jerry

[opnspaces]

Bob2952 wrote:
Just bought my first RV. It's used with 2yr old tires.
I'm planning a long trip and all the talk about the tires is confusing. My travel trailer is 28ft with dry weight of 6000 lbs.
The tires say maximum cold tire pressure is 80 psi.

Because the tires are ST are they safe to use with 80psi and an average speed of 60mph? Everybody has opinions but I would like to know if anybody has the same tires with good results?
Thank you

If the tire is rated at 80 PSI COLD then yes it's safe to run them at 80 PSI COLD. Cold means first thing before you pull the trailer. the tires will heat up as you drive and that will increase the PSI. That is normal and expected. The engineers have figured that expansion and pressure increase into their design. Never let air out of a hot tire to bring it back to the Max Cold rating on the sidewall. If you do that then you will be underinflated when the tire is cold.

Same thing with your car tires and the pressure rating on the sticker on the drivers door jamb. The rating on the sticker is for a cold tire not a hot tire. Don't let the oil lube guy let air out of your tires to bring them down to the sticker pressure. If so you'll be underinflated when cold.