Mixing Load Range D and E on TT

I am with Grit Dog, that is no biggie. I did it once with D's on one axle and E's on the other. Was on a two tire budget then. :W

Now that is something that I wouldn't do. If I were to mix "D" and "E" rated tires on my trailer, I would want a matched pair on each axil.

I would run 75-80 in the E tires and run them on the driver's side, because it is dangerous working on the traffic side. Put 65 in the D tires and run them on the passenger side.

80 psi isn't going to wear the center of your E tires. I have run 3 sets of E's thousands of miles and they showed even wear.

Roll resistances are different between them

Braking will be different between them

Roll-over of the side walls will be different between them

Slip angle will be different between them (this is seldom understood
and less how it affects tire handling...even longevity)

Of course weight carry rating will be different between them. You
have to air up the lower rated tire higher to match the carry capacity
of the higher rated tire in order to balance the load carrying



Then at what PSI each tire is at will factor *ALL* of the above



A bit better or less risk (on the good days out there) since no steer axle on
this trailer, but if there is a steer axle, then dangerous...

Dangerous...mainly on the day Mr Murphy crosses your path...either you have the
right stuff spot on or not. No time to go back to the store for proper stuff

Note that all things engineered and specifications/ratings/limits/etc written
are NOT for the good days out there...but for the worst case situation(s)...



Have no skin in the OP's situation, but am writing mainly for the
lurkers who might think this is a good/okay thing...it is NOT and a
risk management decision (AKA gambling) that Mr Murphy won't cross
your path...

http://www.rvtiresafety.com/2013/11/interply-shear-and-other-techno-babble.html

Check out Tireman9 tire safety website. Eliminates rooky mistakes that we all make about using a minimum pressure from a tire chart in our tires in a trailer position vs tires on our tow vehicles. Apples vs oranges. Trailers can be over tired unlike our trucks.

Tires on a trailer perform best for long term use when properly matched to the trailers GAWRs with say 10-15 percent reserve capacity. This way the tire can be ran at max pressures and doesn't have to be derated.

Now if your the type that runs say 6k-10k in 5-6 years then run the tires the way those that poo poo tire advice if that benefits you the most.
Or if your the type that puts 40k-60k miles on a trailer and expects them to last 5-10 years then pay attention to tire experts/tire engineers like Tireman9 rvtiresafety.com blog.
Spend some time looking at his advice on tire tech for trailers.

It's fine. As long as the trailer tires are all up to the weight you're putting on them and if you have torsion axles they need to be same diameter. If leaf springs them diameter is not n issue within reason.

JIMNLIN wrote:
Also due to braking rotational forces the rear axle brakes tend to lift the front axle a bit through the equalizer bar on hard braking events. If I had tires different in diameter I ran the larger diameter tires on the front axle. Doing so helps eliminate flat spotting.

I hadn't thought about this. Do you think spread axles would behave differently? I would have guessed that the front axles would get more weight on them in a hard stop similar to what happens with a car where the rear tires unload.

scbwr wrote:
I would go ahead and buy two more Maxxis tires and not have to be concerned about any potential problems from running different tires on each axle. On the other hand, you could take it down the road on a trip and see if you have any problems.

Right now the jury is still out on these tires. Just one went bad. If I catch a second one going then the other two will be gone.

Here's what the bad one looked like:

mkirsch wrote:
You can run the E-rated tires at 65PSI no problem. They are only carrying a D-rated load, and only need to be inflated to D-rated pressure to carry it.

In fact at 80PSI you will probably see abnormal wear in the middle of the tread.

I know I can run them at 65 PSI. I didn't consider that the wear might be an issue. I suspect that the tires will age out before they wear out though.


Isn't heat the biggest enemy of these tires - and higher PSI == less heat?

Also, when backing and scrubbing the tires, won't more pressure keep the tire more stable and give a slightly higher chance of preventing damage from side pressures?


I had individual wheel weights done with full fresh water and packed for a trip. Here are the readings:

Left Front 2000
Right Front 1900
Left Rear 1800
Right Rear 200

Maxxis has a load chart for ST225/75R15 tires:


PSI Weight
25 1430
30 1600
35 1760 (B)
40 1880
45 2020
50 2150 (C)
55 2270
60 2380
65 2540 (D)
70 2620
75 2720
80 2830 (E)


Why not just run the tires at 50PSI since I know the max weight with full water tank ready for a trip is 2,000 lbs per axle?

mkirsch wrote:

People need to understand that the maximum inflation pressures are not law. There are no "tire pressure police" lurking in the bushes waiting for you to only put 79psi in those load range E tires, so they can drag you and your family off to a gulag in Siberia.

Ha. Not worried about tire police. Only interested in maxing out the life of the tires.


Also, I did check and the rims do support 80 PSI as well....



I also found this:



Goodyear: Weighing Your RV

Unless trying to resolve poor ride quality problems with an RV trailer, it is recommended that trailer tires be inflated to the pressure indicated on the sidewall of the tire. Trailer tires experience significant lateral (side-to-side) loads due to vehicle sway from uneven roads or passing vehicles. Using the inflation pressure engraved on the sidewall will provide optimum load carrying capacity and minimize heat build-up.

Thanks.

People need to understand that the maximum inflation pressures are not law. There are no "tire pressure police" lurking in the bushes waiting for you to only put 79psi in those load range E tires, so they can drag you and your family off to a gulag in Siberia.

mkirsch wrote:
You can run the E-rated tires at 65PSI no problem. They are only carrying a D-rated load, and only need to be inflated to D-rated pressure to carry it.

In fact at 80PSI you will probably see abnormal wear in the middle of the tread.

Exactly!!!!!!!!!!!!

You can run the E-rated tires at 65PSI no problem. They are only carrying a D-rated load, and only need to be inflated to D-rated pressure to carry it.

In fact at 80PSI you will probably see abnormal wear in the middle of the tread.