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Texastbird · 05-16-2014, 11:12 AM

Ok, I have done a lot of research on the forums and Google, but still have a question for which I haven't found a definitive answer. I have 225 15 inch load range D tires as standard equipment. Is there a good reason for or against to go to the load range E tires even if the OE tires are well within the load range for my rig? I've heard suggestions of more heat, less sway, and all kinds of unsubstantiated reasons for and against going to load range E. My rims are rated for load range D so I would not run the pressure over 65psi, as I have with the original tires. Anyone care to tackle this one again?
Thanks, Tim

Skip426 · 05-16-2014, 11:49 AM

Although I'm a believer in a good , heavy tire and have replaced with higher load ratings several times with no ill effects. I'd never gone with a tire that was capable of more pressure than the rim was rated for.
You might even have trouble getting a tire store to mount the tires on an under rated rim.
Note: A big reason for tire failure can be the rubber valve, I'm a believer that, any tire and rim combo that requires more than 50 PSI. should have a metal valve installed.

Texastbird · 05-16-2014, 12:10 PM

Yeah, I would bet that is something a lot of people don't think about (me included), the correct valve stem for the type of tire and service. MY TT came with the "el cheapo" Akuret tires made in China. I have gotten good service out of them, but with the outer edges starting to wear down, I am about ready to move to something better before I tempt fate too much. I won't even go into the which tire is best arena. Personally I rate all mainland China tires about dead even. I was lucky to get a set that has served me ok, even with all the blowout and separation stories I have read about the Akurets. So I will probably go with the tire rated the same as the factory rims, which is load range "D". Maxxis, if I can find some locally here in the Houston area.

nomad297 · 05-16-2014, 05:11 PM

How do you find out what your rims are rated for?

I have asked this question many times here and elsewhere and nobody has given me an answer.

Thanks,

Bruce

Franka548 · 05-16-2014, 07:28 PM

nomad297,
Somewhere stamped on the rim is the load rating and the maximum pressure for the rim.
Frank

DavisK · 05-16-2014, 07:43 PM

Quote:

Originally Posted by Skip426

Note: A big reason for tire failure can be the rubber valve, I'm a believer that, any tire and rim combo that requires more than 50 PSI. should have a metal valve installed.

Rubber valve stems can take as much pressure as rubber tires. My Silverado came from the factory with E rated tires and rubber valve stems. I run them with 70 - 80 PSI all the time with no problem or loss of pressure.

JIMNLIN · 05-16-2014, 08:43 PM

There is no benefit of a E tire at 65 psi over the D tire at 65 psi.

Having up to 5 trailers on the road at one time and close to a million miles towing trailers I found the folly of derating a tire with less pressure. It was a expensive lesson and one that my truck tire dealer warned me not to do. Being 30 years old I knew different. LOL
I wound up with hotter running tires and we all know about heat and tires don't mix well.

This from Tireman9 (Roger Marble who is a actual tire engineer with some very good advise for new folks to pulling trailers in his tire blog)

Tireman9
rvtiresafety.com

The question of load capacity and Load Range gets asked a lot, so it seems to be a bit of a stumbling block for a number of RV owners. Here is an example:
"I need to replace the ST235/75R15 tires on my trailer. Currently have load range C tires which is sufficient for the maximum trailer weight when inflated to 50psi but allows almost no safety margin. I want to change to either load range D or E tires. My rims are only rated for 65 psi so if I went to the load range E tires I would only be able to inflate them to 65 psi. My question is this. Is there any advantage to a load range E tire used at 65 psi vs a load range D tire at 65 psi?"

Now just because he is asking about a 15" trailer application and considering a change from LR-C to LR-D it does not mean the general answer does not apply to others, even if they are considering a change from LR-G to LR-H on a Goodyear 295/75R22.5 Class-A tire.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>

The answer to the question is;
He will gain a safety margin if he increases his inflation to 65psi with LR-D but if he stays at 65psi there is nothing further gained by going to LR-E as there is no difference in the capacity at 65psi.

Texastbird · 05-16-2014, 09:29 PM

I think my aluminum rims came with a little sticker on them advising of the maximum load and pressure, but it may be stamped in the metal also. Thanks for the info Jim, that is the conclusion I had come to, but I am not an engineer, by any stretch. I will make sure when I get the tires, I will ask about the valve stems being of the correct type and rating.

Texastbird · 05-16-2014, 09:46 PM

Nomad, I went out and looked at my spare. It is a steel wheel, and the DOT info is stamped inside of the rim. I couldn't see it in the dark on the Aluminum wheels.

Cumminsfan · 05-16-2014, 09:50 PM

They don't put PSI ratings on newer rims anymore. Only load ratings. Load ratings correspond with psi. IE my rims have 225/75/15 D rated ties on them which carry a load rating of 2540lbs per tire. My rims are rated for 2830lbs which corresponds with E rated 225/75/15 tires. I could then move up to E rated tires and run them at 80 psi.

nomad297 · 05-17-2014, 12:34 PM

Ok. I found on my rims where it states 2,600 pounds max. Does this mean I can't inflate my E rated tires to 80 psi? What can happen when a rim is over inflated?

Bruce

Texastbird · 05-17-2014, 05:15 PM

So Bruce, did your TT come with E rated tires, or did you put them on yourself? I can't figure out how they decide what rim gets what rating. They all look about the same to me, unless you move up to the next larger size, say from 15 to 16inch. Logic would dictate that one wheel of 15" diameter would have to be built stronger to receive an E rating as opposed to a D.

Ste · 05-18-2014, 03:03 PM

Davis, your truck tire tire valve stems are also the tpms sensors and have a brass tube in the center with rubber molded around it. They're are high pressure valve stems for D and E Load ranges that are also rubber molded over brass.

Steve

JIMNLIN · 05-18-2014, 07:23 PM

Quote:

Originally Posted by nomad297

Ok. I found on my rims where it states 2,600 pounds max. Does this mean I can't inflate my E rated tires to 80 psi? What can happen when a rim is over inflated?

Bruce

Looking at Dexstar wheel catalog shows a 15" 2600 lb capacity steel wheel is good up to 75 psi.
Never assume any wheel can carry the higher pressures. I see 15" steel trailer wheels rated at....
.. 50 psi and 1820 lbs capacity
.. 65 psi and 2050 lbs capacity
..75 psi and 2600 lb capacity
.. 80 psi and 2830 lbs capacity.

Many of the imported trailer wheels have no pressure ratings stamped or a sticker. My truck tire dealer sells steel wheels and will not accept a shipment of wheels without a pressure rating. Big liability issue for the retailer if he mounts a E tire on a wheel not rated for that pressure.

Having pulled equipment/flatdeck trailers for a living I've seen many split and cracked truck and trailer wheels from using the wrong pressures and carrying heavy loads. Over pressuring a wheel is best left to cars and hot rod trucks.