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

[atomlinson]

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.

[wa8yxm]

Can you go from a "D" to an "E": YES

What about the max pressure...

Now: Many people think they should always just run the Max Pressure, and this is ... Occasionally (Very rarley) correct.. usually you should be running less than max..

How much should you run:

This is a two step question/answer

Step one. WEIGH THE trailer, idealy you weigh each side. but if you can not do that weigh the thing as it is hooked to your tow vehicle, then while you are at it drop the jack ON THE SCALE, lift it off the tow vehicle and get another weight (GVW) just for reference, we won't be using that but it is nice to have.> Weigh it loaded as though setting out on a trip, Full fresh tank, empty waste tanks.

Now divide by number of tires (The axle (hooked up) weight.

Go to the tire maker's web site and download the tire's inflation chart

So many pounds (the results of the division) = So many PSI per the chart

That is the proper inflation.. Some folks like to add a few (up to 5) PSI, Myself among them.

[RBPerry]

They're not needed on every trailer, but if you're a heavy trailer and hauling heavy loads, go with the LT tires. They still have enough flex to not beat the trailer to death.

I'm currently negotiating the purchase of the new TT, and have told the dealer I will not purchase it with the current (in my opinion cheap foreign tires). I want quality LT tires such as Good Year or Firestone. I definitely don't want a 10 ply rated tire, I fear the trailer would ride like a tank. For some reason the dealer seems very reluctant to replace the tires, but that is a deal breaker for me.

[DSDP_Don]

I have a different opinion on what to use. Ours friend bought a brand new Cameo fifth wheel which weighed 12K empty. Within the first year the poor quality foreign brand trailer tires came apart and caused some damage. I told them to skip the trailer tries and install LT (light truck) tires instead. Cameo replaced the tires with another foreign brand, that a short time later came apart again. This time they went with the LT tires and have had no issues since.

They're not needed on every trailer, but if you're a heavy trailer and hauling heavy loads, go with the LT tires. They still have enough flex to not beat the trailer to death.

[atomlinson]

Thanks so much for the replies so far, everyone. FYI my TT is the front-load toy hauler type, however no atvs, motorcycles, are being hauled in the garage area, just chairs, grill, bicycles, etc. Golf cart will be loaded in the bed of the truck. FWIW

[coolbreeze01]

atomlinson wrote:

My question: Can I go from a "D" to an "E" range tire?

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.

I have upgraded C's and D's to E's on different trailers. Having had good luck with E rated tires, I recommend them.

Yes, an E rating is what used to be 10 plys.

[fla-gypsy]

I did exactly what you are considering and am pleased with the result. My rims have no psi rating stamped on them in spite of all those who claim they do only a total load rating. I run the pressure to match the load rating listed on the tire makers website and gained some reserve capacity. The likelihood a steel rim will fail a few lbs over the original rated pressure is minuscule and a risk I'm comfortable with

[phillyg]

Seems that most tires now carry a designation of the number of plies, for example, 10 ply, but they add the word "rating," which allows a tire to be manufactured with less than 10 plies but still be the equivalent of 10 plies. Ahhhh, the magic of advertising. Generally, 10 ply is E and less than 10 ply is D, and so on. Wheel manufacturers apparently don't have standards so their PSI stamp can be anywhere on the wheel, even under the tire, and they may not use PSI, rather they'll state the max load rating, for example, 3400lbs., which would equate to a 110psi, or E tire.

[3oaks]

atomlinson, the short answer to you thinking is correct but your tire pressure will be restricted to what your rims are rated for. "E" tires will give you an extra margin against tire blowouts but will not increase your GVWR due to all the other components of your trailer. And "E" range tires have a higher ply rating than "D"s.

[jmtandem]

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.

[Matt_Colie]

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

[Sandia_Man]

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]

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]

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.