Hi gang. I know, I know, another tire subject. But I need help. Yes, I used the search feature, but didn't quite find what I was looking for, so here goes:I'm getting ready to purchase new tires for the TT for our big haul to Florida in June (week 1 will be at Disney- Ft. Wilderness, week 2 will be at Camp Gulf in Destin). I still have the original tires on, so time for some new skins. Size 225-75-R15, "D" range. Looking at different brands, including, of course, Maxxis. My question: Can I go from a "D" to an "E" range tire? I saw where the max air pressure is greater in an E as opposed to a D, and thought I read somewhere about it depends on how much pressure your rims will allow. I figured more is better, so I was leaning towards an E tire, but don't want to get more than what my rims will allow.Ok, another question: Plys. Is a D tire considered 8 ply, and an E tire considered a 10 ply?Thanks in advance. I greatly appreciate any help. Be gentle.

PSI rating should be stamped on the rims. If not, then there should be enough stampings that you can do a google search and ask them. Remember tire load ratings are at full rated pressure. Most tire mfgs will have a load raring chart that will show you load at PSI.

The trailer we just sold came new with D rated ST tires...something called Missions.???We replaced them with load range E Maxxis. We did not replace the wheels. Worked great. No tire problems for the 5 years we had them.I ran them at 75 psi.

Back or inside of rim will have psi stamped, if they are rated for max 65psi it would be best to stay with D rated tire and Maxxis would be your best bet as ST tires go. Got 5 years out of my last set of Maxxis ST tires in your size and our rig is about 10K# loaded for travel. Best to run ST tires at or near max psi, much lower and they will overheat leading to premature failure. Thought about going to E rated myself but rims would not support 80psi and the D rated Maxxis tires could handle over 10K# anyway. If your rims can handle the 80 psi go for the E rated Maxxis. Not sure about amount of plys but the E rated tire is heavier than D rated which is heavier than C rated and so on. Have a great time in Florida and at Disney!

Andy, Yes - is the answer to your first question. Yes - is the answer to you second question. Now, the explanation for those that need it. Load range of a tire is just interest. The tire should be inflated to match the load on the tire most of the time. Weigh the vehicle before you buy tires and have the installer match inflation to the weight. The rim strength only matters if you are going to over load the vehicle and then you will need new rims and maybe axles and bearings. The difference between load ranges (what used to be ply ratings based on the actual tire construction) is also less important these days. The difference these days is more likely (if there is a difference) to be the construction of only of the plys of the tire. Many times there is no difference. This is why D and E range 16" tires are often the same price. If the D is less, it is only because if they sell it for less, they expect to pay less warranty on that tire. Matt - Detroit OE refugee

To gain the additional carrying capacity of the higher rated tire you will need higher air pressure. That essentially will beat your coach to death unless the air pressure is correctly matched to the load. And in that case the tire might not carry more weight than the D tires. There is some research you might look at with the tire shops to see if E is better for you than D. I would not be concerned going up 10-15 percent in capacity, but not much more than that.

Tires! (yes, tires, again...bear with me) | Good Sam Community

13 Replies

Sandia_Man
Explorer II
Mar 20, 2016
Back or inside of rim will have psi stamped, if they are rated for max 65psi it would be best to stay with D rated tire and Maxxis would be your best bet as ST tires go. Got 5 years out of my last set of Maxxis ST tires in your size and our rig is about 10K# loaded for travel. Best to run ST tires at or near max psi, much lower and they will overheat leading to premature failure.

Thought about going to E rated myself but rims would not support 80psi and the D rated Maxxis tires could handle over 10K# anyway. If your rims can handle the 80 psi go for the E rated Maxxis. Not sure about amount of plys but the E rated tire is heavier than D rated which is heavier than C rated and so on. Have a great time in Florida and at Disney!
downtheroad
Explorer
Mar 20, 2016
The trailer we just sold came new with D rated ST tires...something called Missions.???
We replaced them with load range E Maxxis. We did not replace the wheels. Worked great. No tire problems for the 5 years we had them.

I ran them at 75 psi.
donn0128
Explorer II
Mar 20, 2016
PSI rating should be stamped on the rims. If not, then there should be enough stampings that you can do a google search and ask them. Remember tire load ratings are at full rated pressure. Most tire mfgs will have a load raring chart that will show you load at PSI.

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Tires! (yes, tires, again...bear with me)

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