Suprising answer from wheel manufacturer re: wheel PSI rating. Thoughts?

[JohnRT]

I am impressed at all the great information that is backed up by Charts and MFG's facts and figures. I would like to also add something that seems to be overlooked. In the Data information following the thrad to the Transeagle tire one thing JUMPS out to me. The Speed Rating is L which relates to 75 mph max. All the stats on anyone's sheet like this is based off of Max PSI. SO if you reduce PSI you also reduce the Speed Rating. Also to feel the stiffness and beefier sidewalls and tread increases durability i feel this is a totally wrong approach. The compounding of the Rubber on sidewalls and treads is what increase or decreases durability. The Compounding in all tires for all vehicles is different for bead areas, sidewalls, tread edges and tread. I would never recommend anyone ire up with out changing wheels to match tires, changing axles which will also update studs, nuts, bearings, seals, brakes and load carrying capacity. i totally understand what owner is trying to do, just upgrading tires is not the proper fix. Here is one more thought. What happens if vehicle is sold?

[NorCal Hal]

"but now I'm tempted to throw on high-pressure valve stems and air them up to the max G-rated pressure of 110psi."

WHY would you want to, because you can???

EVERYONE should know the weight of their trailers, motorhomes, boats, etc.! You should weigh your fully loaded trailer, or add in the weight of water, clothes, equipment, food, tools, toys, etc. to the empty vehicles weight. But is FAR better to have it weighed FULLY loaded then look at the tire manufacturer's inflation guide for the weight it will ACTUALLY carry. Add 10 psi if it makes you happy. I just use the next higher weight group on the tire company's chart. Your front tire inflation and rear will most likely be different. On HOT days on HOT highways you may find over inflation is as bad as underinflation. I have a TPMS on ALL my vehicles: cars, truck, toy hauler , motorhome and a portable unit I install on my towed vehicles and rented trailers. On a recent hot day my tires, which were inflated to 110 PSI cold, were reading 140 PSI. I can actually read the difference in tire PSI on the sunny side of the vehicle from the shaded side. Had I inflated the tires to their maximum safe inflation I might have been close to 180 PSI on that day. WAY too much hot air. Pun intended.

[bluehaven]

Its still a chinese tire, that's the part that scares me. The speed rating on the tire is L, which is 75mph. The Goodyear Endurance is rated N, 87mph. Never had good luck with the chinese tires.

[Tireman9]

Originally Posted by Old-Biscuit

PSI is directly related to Load rating

Running 'G' rated tires at 80 psi is not good for the tires

Running 80 psi rated rims at 110 psi is not good

Either buy higher rated rims that are rated for 100 psi use
or Buy 'E' rated tires

Wondering where you found actual data to support the claim that running LR-G tires at 80 psi "is not good"? I agree that running a LR-G tire at 80 psi is not good if the tire is loaded higher than the tables indicate for 80 psi inflation.

[NeilV]

Originally Posted by msh45

Just got off the phone with a lady at Dexstar, who manufactured my tt wheels. I was calling to get the details on the PSI rating of my wheels (I recently purchased upgraded 14-ply, all steel radial, G-rated tires that can handle up to 110psi). Dexstar publishes load ratings (in lbs) for all their wheels on their website, but the pressure rating is nowhere to be found on their site.

Given that my 15" wheels have a load rating of 2860 lbs, I expected to be told they had a PSI rating of approx. 80lbs, but she informed me that while this is a common concern, they removed all PSI ratings from their website several years ago, as they are concerned only with the load on the wheels. "The tires will give out long before there is any issue with the steel wheels due to pressure".

Bottom line, she green-lit me to run a full 110psi on my 15" wheels with a 2860lb load rating. I was planning to run the new tires at 80 psi, given that the tires will still be approx. E-rated at that pressure, but now I'm tempted to throw on high-pressure valve stems and air them up to the max G-rated pressure of 110psi.

Thoughts?

Upgrading to load range G tires does not automatically mean you have to inflate them to a higher pressure. You have to weigh the trailer to see how much it weighs and if over the trailers manufacturers max gross weight rating then lightened it up. The stiffer load range G tires may actually be able to carry the same amount of weight as the load range E tires at the same or potentially lower PSI. Higher PSI than required by the load just adds more stress to the suspension, frame and structure of the house on the trailer along with all its contents and can cause it to drift and be more prone to sway along with prematurely wear out the center of the tire treads.


We see too many folks out there trying to increase capacity by upgrading tires, axles, adding springs, etc however that trailer frame along with the modifications made to it by the coach builder is still a limiting factor which is why we see so many trailers with frames cracking at the A frames and where the springs are mounted.


Over inflating tires beyond whats required to carry the load on them can be just as bad as under inflating them.

[Rode Dog]

As stated by Old Biscuit and others PSI is based on load carried. If you look at tire load rating chart you will see a tire pressure recommendation increases as the load increases and converse is true also. Knowing weight carried ( not capacity) by each axle will allow you to fine tune pressure. Normally increasing tire capacity or size isn't necessary unless weight carried is changed.

[Marshalone]

When I towed my 5th wheel I was advised by several other 5th wheel owners that unless my tires were G rated I should not run faster than 65 mph. If I did, I risked blowing tires on a regular basis. I had G rated tires and don't know how true this is but if it is, most people are not aware as they pass me on the highways doing 70+ on the way to their destinations.

[frizfreleng]

[QUOTE=Old-Biscuit;5848436]PSI is directly related to Load rating
Running 'G' rated tires at 80 psi is not good for the tires
Running 80 psi rated rims at 110 psi is not good
Either buy higher rated rims that are rated for 100 psi use
or Buy 'E' rated tires[/QUOT"E]

As per the OP "....but she informed me that while this is a common concern, they removed all PSI ratings from their website several years ago, as they are concerned only with the load on the wheels. "The tires will give out long before there is any issue with the steel wheels due to pressure"."

[msh45]

Originally Posted by dtucker300

Surely there must be a OEM sticker that indicates the recommended pressure. Otherwise, why not just put 30 PSI in them and call it good enough?

Not sure what you're implying, but I'm not exactly flying blind here. I've personally contacted both the wheel and tire manufacturers to get info; the latter provided load inflation chart for my exact tire. I'm doing my due diligence, quite the opposite of "just putting 30 psi in them and calling it good enough". I mean, c'mon.



The OEM sticker states 65psi. Stock D tires at their 65psi max only provided 3.5% excess capacity over GVW, and if I ever need to travel with my tanks full(ish), my actual weight would be within 7% of D-rated load limit.


That said, I've inflated these to 80psi (E rating), which matches the wheels' load rating, and gives me a bit more breathing room. I'm not trying to increase the carrying capacity of my trailer so that I can overload it, just upgrading the link in the chain with the load rating nearest to my GVW.


I'll do a chalk test, and may end up adjusting a bit more (likely down), pending the results.

[KanzKran]

Originally Posted by msh45

Transeagle ST Radial All Steel ST 225/75R15 124/121L G (14 Ply) Trailer Tire

Originally Posted by jadatis

American pressure/ loadcapacity- lists give all the loadranges of same sise in one list, and I dare to state that is wrong. Europe makes seperate lists for every loadrange( called plyrating here in Europe).

Originally Posted by Tireman9

Wondering where you found actual data to support the claim that running LR-G tires at 80 psi "is not good"? I agree that running a LR-G tire at 80 psi is not good if the tire is loaded higher than the tables indicate for 80 psi inflation.

I'd be curious to know what Tireman9 thinks of this line of reasoning. Load/pressure tables I've seen all show the same inflation pressure/load combo for all tires in the series, but limited to max load by load range, like in the table above. And if European tables are different for different load range tires, how much do they differ?

I've always just assumed more plies means higher load and pressure capability, but due to geometry (the same across load ranges), a given pressure should be able to support a given load with the same deflection (and therefore flex) as any other tire of the same geometry, regardless of ply rating. But I could be wrong.

[Tireman9]

Originally Posted by KanzKran

I'd be curious to know what Tireman9 thinks of this line of reasoning. Load/pressure tables I've seen all show the same inflation pressure/load combo for all tires in the series, but limited to max load by load range, like in the table above. And if European tables are different for different load range tires, how much do they differ?

I've always just assumed more plies means higher load and pressure capability, but due to geometry (the same across load ranges), a given pressure should be able to support a given load with the same deflection (and therefore flex) as any other tire of the same geometry, regardless of ply rating. But I could be wrong.

I agree with the "assumption" in the 2nd part.

[msh45]

Originally Posted by TRAKKER

If not mentioned, you must use a tire pressure monitor. I like the Tireminder because it displays all tire pressures at once. Otherwise the only notice of a tire failure will be someone driving alongside hollering you are on the rim.

Thanks -- I actually am not running TPMS currently, but I do check for proper inflation 100% of the time before I get on the road. Given that it's a single-axle trailer, is there a chance I wouldn't know? I'm going to get TPMS regardless, but I assumed I'd know immediately as I only have the one tire per side.

[msh45]

Originally Posted by Tireman9

I agree with the "assumption" in the 2nd part.

Thank you, I'm glad to hear your opinion on this. Your blog has been a valuable resource for me.

[msh45]

Originally Posted by NeilV

Upgrading to load range G tires does not automatically mean you have to inflate them to a higher pressure. You have to weigh the trailer to see how much it weighs and if over the trailers manufacturers max gross weight rating then lightened it up. The stiffer load range G tires may actually be able to carry the same amount of weight as the load range E tires at the same or potentially lower PSI. Higher PSI than required by the load just adds more stress to the suspension, frame and structure of the house on the trailer along with all its contents and can cause it to drift and be more prone to sway along with prematurely wear out the center of the tire treads.


We see too many folks out there trying to increase capacity by upgrading tires, axles, adding springs, etc however that trailer frame along with the modifications made to it by the coach builder is still a limiting factor which is why we see so many trailers with frames cracking at the A frames and where the springs are mounted.


Over inflating tires beyond whats required to carry the load on them can be just as bad as under inflating them.

Yes, if I could edit my first post I would add an "Update:" at the bottom of it -- I was set straight pretty quickly that I shouldn't go up to 110psi without the load. I was still learning and had read several places that "ST tires should always have max sidewall pressure in them", and I have since discovered the load inflation charts, and become convinced via conversation here and research elsewhere that this is not always the case (if it were the case I readily admit I would need to buy new D or E tires given my load).

To be clear, I am not trying to increase the load capacity of the tires because I am currently overweight, or to allow me to carry more weight -- I just want to run with a bit more operating margin for safety, and take advantage of the added durability of the 14-ply tires.