Load range E--ST Tire

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.

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

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

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...

^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.

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.

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)

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?

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.

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.