Changing tires from load range D to E

danimal · 09-03-2013, 07:24 PM

I have read so many posts about tire blowouts and resulting trailer damage I thought that I should inspect my tires a little closer. I always check the tire pressure before I leave on a trip and almost never have to add air. After a close look, there is some cracking in the tread area and slight cracking half-way up the sidewall in a perfect circle on the front and back of the tire. I did not buy the trailer new. I believe that I need to replace the trailer tires and am on a limited budget.

Currently, I have Duro ST225/75/15 with D load range with 50psi max. I found some Power King tires online (same size) which are E load range radials 80psi max. I know I do not need E load range tire but it is the best deal that I have found. I really don't want a discussion that these tires are are crap and I should really get some other brand I could just really use some help. I have the standard steel wagon wheels and realize that probably 65psi is max. Would it be OK to install these tires and run them at 65psi? My truck tires are E and the fronts are inflated to 65psi and rears are at 80psi, seems like it would be OK to run the E trailer tires at 65psi. Thanks in advance for any help.

**JRTJH** · 09-03-2013, 09:16 PM

Go here and check the technical specs on both the tires. http://www.powerkingtires.com/Tires/Trailer/ST%20Radial

They are "essentially" the same, and as you indicate, max pressure is 80PSI.

I have no idea what wheels you have, and they could pose a problem for you regardless of their max PSI rating. First, if they are 5 lug wheels, they probably are only 5" wide. If they are 6 lug, they are probalby either 5.5" or 6" wide. The powerking 225/75R/15 LRE require a rim width of 6", so measure that as well. Many of the 6 lug 6" wide rims are rated at 80PSI, so you may be OK regardless of what you plan to run for pressure. If you are going to run pressure below the tire recommended max PSI, I'd urge you to get a laser thermometer to monitor your tire temps. Remember the two biggest causes for ST tire failure are operating the tires with low pressure or overloading the tires.

danimal · 09-04-2013, 06:50 AM

I have 6 lug rims. They are difficult to measure but they are about 8" from outside lip to lip which does not seem right. I must be measuring in the wrong place.

danimal · 09-04-2013, 07:05 AM

Finally found the DOT date code on the tire: X2VX 1504. 15th week of 2004, oh my god! I just changed from "I believe I need new tires" to "I am going to get new tires before my next trip".

Festus2 · 09-04-2013, 07:21 AM

danimal -
I recently changed my tires (225x75R x 15D) from D to E. My previous D's were rated at 65 psi and the new ones (Maxxis) are 80 psi and the same size of course. Before buying them, I carefully examined the white, steel rims and found out that they are rated at 2800 lb and 80 psi. The stats on them are 15"d, 6"w, bolt pattern 6 on 5 1/2 centers.

Are you sure your tires are D load range with 50 psi? Doesn't matter much now in view of your recent discovery mentioned above. If your wheels are aluminum, they may have a different rating even though they might be the same size as my steel ones.

CWtheMan · 09-04-2013, 10:58 AM

Quote:

Originally Posted by danimal

I have read so many posts about tire blowouts and resulting trailer damage I thought that I should inspect my tires a little closer. I always check the tire pressure before I leave on a trip and almost never have to add air. After a close look, there is some cracking in the tread area and slight cracking half-way up the sidewall in a perfect circle on the front and back of the tire. I did not buy the trailer new. I believe that I need to replace the trailer tires and am on a limited budget.

Currently, I have Duro ST225/75/15 with D load range with 50psi max. I found some Power King tires online (same size) which are E load range radials 80psi max. I know I do not need E load range tire but it is the best deal that I have found. I really don't want a discussion that these tires are are crap and I should really get some other brand I could just really use some help. I have the standard steel wagon wheels and realize that probably 65psi is max. Would it be OK to install these tires and run them at 65psi? My truck tires are E and the fronts are inflated to 65psi and rears are at 80psi, seems like it would be OK to run the E trailer tires at 65psi. Thanks in advance for any help.

A lot of the government regulations are written so there will be an even playing field for all participants.

Rims that are rated for 65 psi are what they say they are. The manufacturing and certification processes has taken into account the amount if tire pressure increases that will be normal when the tire heats up from down the road usage. It may go as high as 80 psi before there is risk of failure. Any tire aired to 65 psi would be a safe application. However, you may not be the only owner and/or servicer of those tires that have a sidewall pressure of 80 psi. People familiar with trailer tires may just normally think they are low on pressure and air them to 80 psi. That would cause the rims to be severely over inflated when at highway speeds and cause them to be at high risk for failures.

CW

gearhead · 09-04-2013, 01:52 PM

These seem to be what folks are buying (including me):
http://www.maxxis.com/Industrial/Trailer.aspx

therink · 09-04-2013, 02:06 PM

I went from 225/75/R15 LR D Towmax to LR E Maxxis in same size on my last fiver and oh what a difference. Those Towmax tiresmare junk in my opinion (compared to the upgraded Maxxis). Just make sure your wheels can handle 80 psi and you should be good. It doesmno good to upgradeto Es if you can only run 65psi in them. Make sure you have them balanced.
Happy trails
Steve

danimal · 09-04-2013, 05:06 PM

My bad, the tires on the trailer are 65psi and I am not really sure where I got 50 from. I check the pressure every time I leave and my Corvette tires are not 50psi either. Thank you for all for the helpful info which has enabled me to make a decision.

Right now I need new tires as we have a short 160 mile trip planned to the Naval Station Mayport (Jacksonville) leaving in a week and these are the ones I can afford this week. Been a rough couple months financially (hospital, medical & dental deductibles). I bought the 225/75/R15E tires for $358 with free shipping from the internet and I know someone who will mount/balance/install all of them for $50. I realize that they may not be the best rated tires but unlike some of you folks, I don't travel 6000 or more miles a year. I average 1500-3000 miles a year mostly in Florida and since I live in the center of state none of the trips are that far. I am disabled and DW is retired and we try to camp 1 week per month. Eventually, we plan a trip out west--Grand Canyon, Yellowstone, etc. Another contributing factor is that I have about the smallest and lightest 5th wheel you can buy (6500 lbs dry), with the D tires I'm not even close to weight carrying limit of 3500 lbs so the tires are not under a great load. We don't carry that much in the trailer, not that much room, and travel dry with the heaviest items in the front compartment. I would have to park a toyota in it to reach the maximum carrying weight limit. Consequently, my guess is that the tires will dry rot long before the tread wears out. For what its worth, I have read about tire blowouts that include every single brand so I think it is a crapshoot however you look at it.

I will check the rims when the old tires are removed to see the weight & psi ratings. The rims are 15X6 6 bolt pattern so I am hoping for the best. I bought new valve stems since they need to be replaced and are good for 80psi if the rims are rated for it.

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