Upgrade tires from D to E

[DC8Captain]

My current TT is setup with tires and wheels with a D rating. I was wanting to purchase a set of Goodyear Endurance tires, 225/75/15, but that size only comes in an E rating now. The E rated GY tire has an inflation psi of 80 while my D rated tires are inflated to 65. I know I will need E rated wheels. The new setup would have stiffer tires and a higher inflation pressure. I'm concerned that with an E rated setup that the ride might be too jarring on my TT. The weight of my trailer won't be matched to the stiffness of the higher rated tires with 80psi in them.

[keymastr]

Not that much difference in ride. And your wheels are probably rated for 80 PSI already.

[BFlinn181]

You don't have to run them at the maximum 80 psi. If your trailer is light, it won't cause as much sidewall flex in the E rated tires. I'd start at 60 psi, then feel the tire heat after 20 miles or so. If they are really hot, increase pressure. If not, keep on rolling. Running them at maximum psi with a light load could cause the center tread to wear faster than the edges.

[memtb]

You will have a far superior tire, rims will probably be rated at or near 80# and you were already only 15# differrence. Air the E's to 70# and be a Happy Camper!

[mpierce]

Run at the same pressure as before. It will carry the weight. And, you will have a better stronger tire. Good move, just do NOT inflate to the 80#. That is MAXIMUM if needed to carry the full rated weight the tire can carry. You are not that heavy, so do NOT inflate that high.

[IC2]

Most if not all tire manufacturers have an inflation table that will show the psig to capacity value. This is Goodyear's:The Inflation Loading - Goodyear RV (you'll have to do a click or two on the RHS to bring it up). As far as your wheels - if they are steel and have a bolt in valve, may be rated up to 94 psig. Aluminum, possibly to 80 psig. You do not have to inflate a tire to the sidewall max though you will lose some capacity level but be well in range of the trailer weight. Additionally, a higher letter number doesn't mean that you will compromise ride but may in fact help the overall handling and ride as well as tire wear and longevity. RV manufacturers traditionally use the minimum tire possible for the rated maximum load shown, usually on a sticker, left hand side of the unit.

[RedRocket]

I just did the same thing by going with the Endurance tires with the higher speed rating along with load rated E. I run mine at 80 psi. Just talk with your tire dealer for their recommendation so long as you trust their opinion. I'm sure it might be in my head, but my TT seems to roll better on the higher pressure tires and I would not consider running lower pressure in them. Also, make sure the wheel stems are rated for the higher pressure.

[monkey]

Our 5vr came with "D"'s.. (china bombs) Before our first trip I upgraded to Maxxis E's, the alloy wheels (15") were rated for the load carried by E's.... So far it was a great choice... No probs, I run the speed I want, (Safely) I've run them from 77-80 PSI, no noticeable difference in temps on our rv. But its not real heavy,,,
Monkey

[SkiSmuggs]

Originally Posted by memtb

You will have a far superior tire, rims will probably be rated at or near 80# and you were already only 15# differrence. Air the E's to 70# and be a Happy Camper!

This is the crux of it. When I upgraded from barely adequate D-rated to E-rated, I ran them at 70-75 lbs and had a stronger tire and better ride with a much larger safety margin.

[Gary RVRoamer]

You don't have to run the E-rated tires at max (80 psi) pressure if you don't want to. They have the same load capacity as a D if inflated to the D max of 65. If that was sufficient before, it's still ok now.
And if you don't use the higher inflation, your existing wheels are fine as well.

[Modersical]

Well, glad I found this discussion. Just bought a 2014 Keystone Outback 310TB that appears to have a weight of 7550 pounds, and I am assuming that is dry weight. It has 2013 year tires, and they have had maybe 1000 miles of road wear. Tread looked new. 65 PSI. I guess they were D rated . . . I could not find a rating listed on sidewall. There was info that said single tire would hold up 2540 lbs, & as a dual, should hold up 2200 lbs.

So my first question is how should I use these numbers to calculate their total weight capacity . . . and, yes, I know I multiply the the above numbers x 4 total tires, but do I count on each tire holding up 2540 lbs? There are 4 single tires on tandem axles, but no actual dual wheels. I've been given to understand that tandem trailer wheels get stressed much more, with sideways pressure as you go around curves and corners; so would it be more accurate to use the dual tire rating??

I headed out for home ~225 miles away. All tanks empty. No toy in garage. Maybe loaded with 150lbs of tools and clothing . . . actually, except for the tools, the same 3 cloth bags of clothing that fit the 3 bags on my Modersical.

I got maybe 20 miles and had a blowout! Tread separated and peeled off, then tire went off like shotgun, fracturing crosswise, from inner bead to outer bead, like it was sliced by knife!

Made it another 180 miles, not quite home, and not sure where it happened, but when I got home, one tire was missing (the right rear, which held one side of trailer up after first blowout), with little left except about a 2" ring of inner bead area, and a few shreds hanging from bent skirt brackets . . . and the upper part of wheel well had the cardboard worn down/up into styrofoam . . . and yes, I realize I need to seal this back up with something! What? Oh, and little fringes of plastic thread hanging in wheel well, like the remains of a cheap plastic tarp that the tire shreds shredded!

20 miles after first blowout, I stopped and got a replacement tire. Their minimum rated tire was an E with 80 PSI MAX. I had them put 65 lbs in it to match others. This is what held up one side of the trailer, for up to 30 miles when the second tire disintegrated/disappeared! So glad I had fresh new E rated tire in this position!

There appears to be rough areas around the outer edges of the empty rim, but the area where the beads seal appears to be unblemished. Does this mean I can just file off the rough scuffed area on edge, and put this alloy rim back in service?

I am familiar with the long standing opinion that tires are subject to dry rot after about 10 years, but I had not considered the beginning of dry rot, starts somewhere earlier. I guess, factoring in the info that the manufacturer has installed the cheapest, tires with barely above minimum weight carrying capacity, that the beginning of the dry rot process does not have to progress very far before your load is at risk for collapse!

Is E rating the heaviest? I never want to go through this again. A flat, I can handle, but a blowout, with tire separation and shredding is some strong destructive forces! The first blowout took out a fender skirt bracket and the wiring to a curbside, lower clearance light. The second blowout/disentigration took out another bracket, and severely goughed out the innerfenderwell, leaving it in definitely an unsealed condition.

Why should the manufacturers not be required to warn the consumers that the bare minimum tires that come on a new trailer, are just "Delivery Tires" and not fit for highway use after 3-4 years?!?!?

I am not as ignorant of TT Tire Safety as I was a week ago, but wish I had had my enlightenment before these two tire failures and concomitant damages!

So is E rating the best, and is it good enough? I am a bit Gun shy now of future tire failures! Hope to find some good sales on Friday after July 4th holiday, but want to make informed decisions.

[jadatis]

Your 80 psi tires would need a bit higher pressure then the 65 psi tires , because they are stiffer and give a smaller surface on the ground at the same deflection.
And the deflection is what counts for producing heat.
Pressure advice is to give the tire a deflection that wont produce to much heat.

The old 65 psi tires where probably also ST ( special trailer) tires , wich are calculated in maximum load for 65m/h , wich gives more deflection allowed.
The new 80 psi tires are also calculated in maxload for 65 m/h so same story.
An LT tire is calculated in maxload mostly for 99m/h , so it gives lesser deflection.
This gives , if you use them for lower speed, a reserve is build in, wich is never bad.
But I can calculate the pressure for you so the ST tire gets lesser deflection, same as LT tire of that sise would have, and still no terrible bumping.
And mayby it then would come to that 80 psi cold.

Already is written here, that your rimms are most likely 80 psi allowed, you can find it on the inside , so have to remove the wheel from the car to find it.

But I rather would take the risk of rimm damage then tiredamage.
In any case, if on inside pressure is given , its cold pressure, and rising of pressure by temperature-rising in tire, is calculated in.
This also counts for tires and valves, maximum allowed is always cold.

One time only , i found a topic about rimms that went leaking because of not having the right pressure rating. Was because of little crackes by to high forces . Gave slow leak, wich was noticed before the tripp.

If tire damages , you notice it when it blows, and then mayby even accident, and injuries, or even death.

So even if you cant find pressure rating of rimm, I would take the 80 psi Endurance, or maiby even beter comparable sise LT -tire with enaugh maximum load to carry the same load.

EDIT: @ motersical
Your tires too also where destroyed by using to low pressure,and not by time.
If to much heat is produced at any part of tires rubber, to many sulfur bridges are created, wich make the rubber ereversible hard, and every next bending of that rubber then tears it a bit further loos, and in the end the tire blows, as happened to you.

This happens at the parts that produce the most heat, so bends the most, and that is where the sidewall goes over to the treath, or even the treath itself, because the iner rubber there has more heat isolation by the surrounding rubber.

So best is to take all tires to that 80 psi tire E-load, and then from the beginning use a higher pressure, wich I can calculate for you , but need accurate determined weights , and no estimation as you do.

As long as you cant produce that accurate weights , give them all the 80 psi , wich nowadays is also the maximum allowed cold pressure.
In earlyer days , they allowed 10 psi higher then that , and even prescribed it for maximum speeds of 75 m/h.
I think that mother nature, still allows that higher pressure then AT-pressure, and once read that tires have teststandards of being able to can stand a presssure ( so also warm) of 2 to 3 times the AT-pressure ( maximum load xxxx lbs AT yyy psi, here the 65 and 80 psi)

If you would have given the already damaged 65 psi , then a pressure of for instance 80 psi too, they would have blown sooner, because damage to structure of rubber was already done, and you new tire , you also gave 65 psi , probably is also already structurally damaged, so I would not trust anymore.

[Modersical]

Thanks, Jatatis, for the insight. The stock tires that blew were D rated and had 65 PSI stamped on sidewall, but you say it is ok ( & should have) to run them with 80 PSI?

The single new tire was an E rated tire, and service center recommended running air pressure the same as the standard issued tires of 65 psi, since that was the tire pressure suggested for supporting the load. ???

My brother has suggested that I get a new set of 4 matched E rated or above tires, and make the single newer E rated tire my spare. ???

[monkey]

NO !!! Do Not run D rated tires at 80PSI !!! Get you some E rated tires. I had trouble finding 15" tires so I went with Maxxis tires (E) So far we have 1 year and several thousand miles at highway speeds, and I'm very happy. Everybody has their favorite brand,, but never heard of anybody liking those 'cheapo china bomb' things. When you get better tires, go ahead and replace the valve stems with better metal ones. Ours are rubber with a metal stem,(new with the new tires) but If I had it to do over, I'd get the bolt in all metal ones so I could some day install a TPMS . But its still a lot better than what came on it.
Monkey