Tire load range

[mabel]

I have been running 225/75 r15 tires on my trailer, load range D.

Have been considering getting load range E. same size tire, and running at lower air pressure, 60 to 65 like I have with the load range D.
Wondered what others thought of this.

[pauldub]

The load range E tires will be a stiffer tire than a load range D. Just run the one that gives you adequate load range. Maybe you need to weigh the trailer so you're not just guessing.

[Optimistic_Para]

myredracer wrote:
Roger Marble's RVtiresafety.net blog and has some posts on the new Endurance tire that are worth reading.

Thanks for posting that. I've bookmarked the site for later exploration.

[myredracer]

Optimistic Paranoid wrote:
My understanding is that lowering air pressure causes the sidewall to flex more than they would at full pressure. More sidewall flexing will cause the tire to become hotter than it would at full pressure. More heat in a tire is never a good thing.

Roger Marble's RVtiresafety.net blog and has some posts on the new Endurance tire that are worth reading.

[Lwiddis]

Any Load Range tire isn’t able to carry their max weight until inflated to max rated pressure. Is a little reading regarding tires on your menu?

So, laknox, when your tires fail and you truthfully say you intentionally didn’t inflate them correctly to manufacturers specs, will you buy lunch for your lawyer after the courts dismisses your case?

[Optimistic_Para]

My understanding is that lowering air pressure causes the sidewall to flex more than they would at full pressure. More sidewall flexing will cause the tire to become hotter than it would at full pressure. More heat in a tire is never a good thing.

[maillemaker]

I run load rated E tires, but they are derated as the rims are 65 PSI only.

Steve

[CALandLIN]

mabel wrote:
I have been running 225/75 r15 tires on my trailer, load range D.

Have been considering getting load range E. same size tire, and running at lower air pressure, 60 to 65 like I have with the load range D.
Wondered what others thought of this.

The official size designation for LT & ST tires includes the prefix. So, your tires are size ST225/75R15 and have a “D” load range letter. That size tire, no matter the brand or load range uses the identical load inflation chart. The LRE tire produces the same load capacity @ 65 PSI as the LRD tire.

Are the ST225/75R15 LRD tires the same size as the original equipment tires? Does your tire placard recommend a cold inflation pressure of 65 PSI for the original tires? If so, a proper inflation for them would be somewhere between 65 - 80 PSI.

Without increasing the inflation pressures above 65 PSI you gain nothing in load capacity reserves (PROTECTION). IMO an inflation pressure increase that would provide 10 - 15% in load capacity reserves is advised.

Note: Make sure the installer changes the valve stems when installing the LRE tires. Steel ones are recommended for all RV trailer tire/wheel assemblies. If snap-ins are used make sure they have an 80 PSI pressure rating.

[JimK-NY]

What do you hope to accomplish by lowering the pressure? I assume you are looking for a softer ride. The tires are only a small component. The stiffness of the ride is mainly controlled by the suspension: springs and shocks.

[laknox]

downtheroad wrote:
If you get E's and then lower their psi....you aren't really accomplishing anything in terms of their load carrying or their reserve capacity.

You =do= get a heavier tire. I did the same, but rarely ran at 80; usually 70-75. I'd go 80 if we were loaded heavy for a long trip, or it was especially hot.

Lyle

[downtheroad]

If you get E's and then lower their psi....you aren't really accomplishing anything in terms of their load carrying or their reserve capacity.

[time2roll]

Go 80 psi. No point in having E unless you add pressure.