D to E rated tires

old guy wrote:
your tire man would know the answer to this question.

Ditto. If not, do a search on the forum, there are thousands of posts on this subject.

Now weigh your truck/trailer combo in fully loaded trim, as if you are on a trip, then fit the inflation into the tables. Remember how many tires you have on the trailer and divide the weight by the number of tires. That is how much load each tire will have to carry.

I've towed trailers since the early '60 for recreational and mostly in my hauling business using same size trucks and trailers we RV with.
Pressure needs on our trucks vs tire pressure needs on a trailer are apples vs oranges. Completely different operational environment.

A couple of points on using just a minimum pressure from minimum pressure charts.
One is loads on tires on a trailer unlike tire on the truck, constantly change especially in strong side winds can over load the tires on the down wind side. Using minimum pressure doesn't account for the over load.
Another point is simply dividing the trailer gross axle weight by 4 tires doesn't take into account one side of the trailer is heavier or one end of a axle is severally over loaded. Minimum pressure charts doesn't account for that over load either.


fifthwheelstreet.com

Step #5..
Selecting the Correct Tire Pressure for Your Trailer
We at Fifth Wheel St. no longer recommend adjusting trailer tire inflation pressure below the maximum load PSI rating molded on the sidewall (and only if the wheel/rim is appropriately rated) regardless of the measured scaled weight of individual tire or axle positions for all multi-axle trailers.

However, we do strongly recommend weighing individual trailer tire positions to ensure none of the axles or tire positions are overloaded. Reports have shown that trailers do not have equal weight across all tire positions. Some RV load configurations may reveal as much as 20% difference between the front and rear axle. This especially true for Toy Haulers. It is possible that mismanaged trailer load distribution will cause one end of an axle or a tire to be overloaded. It has been stated, but never confirmed by any RV Weighmaster, that there are many RVs traveling on the road with at least one tire or axle side overloaded. The only way to ensure tires and or axles are not overloaded is to weigh each tire position on your trailer. Unfortunately, attempting to obtain accurate individual tire position weight is practically impossible at all truck scales. View our list of recommend RV Weighmasters here.

- See more at: http://fifthwheelst.com/step5.html#sthash.FIAc3k0Z.dpuf

SkiSmuggs wrote:
The Load/Inflation chart from Maxxis indicates the tire pressure should be adjusted for the load. When upgrading from D to E, you get additional capacity from the additional air pressure but there is no need to go to a higher pressure than required. FYI, higher pressure makes punctures more likely. I run my E-rated at 70-75 lbs and get a smoother ride than at 80.
Maxxis Load/Inflation chart

What a concept using the charts! Good for you.

My 2 cents, based on many years of RV travel. There seem to be three limitations on tires and their ability to carry a load. Of course these are changed by the user and how we use them.

Each rim has a designed ability to carry weight and hold pressure. They should be stamped into the rim somewhere. If not, contact your RV manufacturer, if they are those that came with the RV (if they are still in business) and they will have that information. If they are after-market wheels contact the wheel manufacturer. As all of us should know, never exceed either rating.

Each tire has a different load rating that is affected by inflation. Each tire manufacturer publishes a tire inflation guide that is available on-line.

Now weigh your truck/trailer combo in fully loaded trim, as if you are on a trip, then fit the inflation into the tables. Remember how many tires you have on the trailer and divide the weight by the number of tires. That is how much load each tire will have to carry.

So, the three variables are; the wheel and its designed limitations on weight and maximum pressure, the individual tire and its construction/weight ratings at different pressures, and the load to be carried.

We should also always be aware of the limitations of age, wear and tear, and deterioration on wheels. They won't last forever and can even break, or be recalled.

Of course, I am not an engineer and this is my opinion.

The Load/Inflation chart from Maxxis indicates the tire pressure should be adjusted for the load. When upgrading from D to E, you get additional capacity from the additional air pressure but there is no need to go to a higher pressure than required. FYI, higher pressure makes punctures more likely. I run my E-rated at 70-75 lbs and get a smoother ride than at 80.
Maxxis Load/Inflation chart

My wheels are 6 hole steel. Thanks for all the info. I am still undecided -- got a little time to decide.

If LT tires you probably need for E-load about 70 psi to get the same loadcapacity as the old D-load. but if you have ST tires you probably would have needed even 75 psi for the D-load/8pr tires to give the tire a deflection , so heatproduction and fuel saving , a comparing LT tire would have .
Then going from D to E-load ST tire would need that 80 psi .
Steel valves is not absolutely needed for E-load , there are also HP rubber snapp in valves that are made for up to 95 psi cold pressure ( so warm higher ). those are yust as easy to fit in the rimm and about same price as normal rubber snap in valves, and can be replaced with every tire chanche.

Ofcource the rimms must be allowed 80 psi then, but that is also given for cold pressure , so must have some technical reserve above that in absulute pressure. So my conclusion is that rims have such a reserve above what is given that using a little higher cold pressure wont damage the rimms that soon.

For that reason I would rather risk going over rimm allowed pressure, then using to low pressure wich can damage the tires and give accidents with damage to trailer or worse injured or dead people.

With this I wont legalise to put a 80 psi tire on a 65 psi rimm, but when putting 65tire on 65rimm , using 75 psi wont give damage to the rimm.

Only found one message about leaking rimms from Dutch rimm maker Prins, that went leaking when going from normal tire ( P-tire with At-pressure of 36 psi in EUR system) to D-load/8pr ( 65 psi AT-pressure).
There the link between allowed rimm-pressure was not made, so I wrote it in the topic. Using 6PR/C-load ( AT-pressure EUR 55psi USA 50 psi ) would probably have given no problems for that rimm.

All my own opinion, burn me down, but with good arguments.

amxpress wrote:
Do you have aluminum or steel rims?
ST tires perform best when inflated to their maximum pressure. Goodyear and Discount Tires states this on one of their sites.
Install steel valve stems.
Balance your new tires
This is the truth.

Best answer!

Especially steel stems.

Lon-Str wrote:
Thinking of going from 8 ply tires on my fiver to 10. It will involve upping pressure from 65 to 80 psi. Nothing but mfg. date on my wheels. Should I be concerned about the extra pressure as far as my wheels are concerned, and the added roughness in the trailer ride?

All wheel mfrs put their stamps in different locations. On =my= Al wheels, they =are= stamped on the back side with "80 psi max". I have also seen wheels, usually steel, that are stamped in the valley so the tire has to be dismounted to find the info. Also, if you have 5-bolt wheels, they are 65 psi max pressure. I upgraded from D to E tires and usually run 80 psi, though, if I'm running particularly light, I will drop to 70 psi.

Lyle

Dtank wrote:

Vulcan Rider wrote:

Lon-Str wrote:
Thinking of going from 8 ply tires on my fiver to 10. It will involve upping pressure from 65 to 80 psi.

What exactly leads you to believe that an increase in pressure would be needed ?? It probably isn't needed at all.

The Max. stamped on the sidewall is NOT the recommended pressure in all applications. It sounds to me like you are putting on tires with a higher capacity and since your actual load does not change, neither should the recommmended pressure.

BAD info!..:(

OP - try checking for the rated pressure on the *back-side* of the wheel. Common location for aluminum wheels.

If it's not there - it might be on the inside of the wheel - but that's doubtful.
The wheel mfgr might be a source - if you know who it is.

(Steel wheels = another doubtful on mfgr source)

Also doubtful that "asking a/your tire man" may help - other than selling you some wheels you may not need.
(However - he might be a good source for the Taco Bell menu from his previous employer..:R..)


Bottom line -
*YES* - you *DO* need to run psi at -or real close- to the max indicated on the sidewall (which is usually 80psi for LR E tires).

.

Totally agree! Why would anyone go to an "E" or "G" rated tire for extra load carrying capacity and then not put the recommended PSI????