D to E rated tires

[Lon-Str]

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?

[jadatis]

Then the brands that specifie the higher maxloads at 80 psi are trying to fit the higher maxload into the stiff American system of E-load always being 80 psi.
Will put remark behind the tires in the quoted part.

Me Again wrote:

Sluggo54 wrote:
"The 225/75 R 15 tire of carlisle and Maxis ( and others like Goodyear) have exactly the same maxload at the same loadrange."

In the US, with few exceptions, the federal government specifies that all tires of a specific size and load rating (E, D, whatever) will have the same maximum load rating (3520, 2840, whatever).

That does not fully apply to ST tires, as some manufactures fumble those numbers.

Here are some examples. The advent of the 7K axle and large RV trailers was in play here!!!! The 80/3420 was the standard until there was pressure for cheap tires to cover a 7K axle. Goodyear is the only one that did not bend to that pressure.

Carlisle
ST235/80R16E inflation 85 lbs 3520 Doing it right because calculate back back with even american formula with power 0.7 gives 3374 lbs wich is lower then normal of 3420

GY Maration
ST235/80R16E inflation 80 lbs 3420 Also OK because 3420 at 80 psi as standard

Towmax
ST235/80R16E inflation 80 lbs 3520Towmax and Westlake both tried to fit the higher maximum load , most likely calculated for 85 psi into the system of 80 psi for E-load so to my opinion wrong atitude, Must be known as C-brand

Westlake
ST235/80R16E inflation 80 lbs 3520

Greenball
ST235/80R16E inflation 80 lbs 3500Greenball used the maximum load AT 80 psi the Loadstar used for 90 psi , Loadstar must be A or B brand and Greenball C-brand.

Loadstar
ST235/80R16E Inflation 90 lbs 3500

Trailer King
ST235/80R16E Inflation 80 lbs 3520Rest all used the Carlisle maxload wich is OK for 85 psi , but use them for 80 psi, wich is to my opinion wrong.
Mayby you can comfirm if all those wrong doing brands are known as C-brand.

Rainier
ST235/80R16E Inflation 80 lbs 3520

Grand Ride
ST235/80R16E Inflation 80 lbs 3520

Arison
ST235/80R16E Inflation 80 lbs 3520

Duro
ST235/80R16E inflation 85 lbs 3520Oversaw Duro with 85 psi using for 3520 wich is OK.

[Me_Again]

Sluggo54 wrote:
"The 225/75 R 15 tire of carlisle and Maxis ( and others like Goodyear) have exactly the same maxload at the same loadrange."

In the US, with few exceptions, the federal government specifies that all tires of a specific size and load rating (E, D, whatever) will have the same maximum load rating (3520, 2840, whatever).

That does not fully apply to ST tires, as some manufactures fumble those numbers.

Here are some examples. The advent of the 7K axle and large RV trailers was in play here!!!! The 80/3420 was the standard until there was pressure for cheap tires to cover a 7K axle. Goodyear is the only one that did not bend to that pressure.

Carlisle
ST235/80R16E inflation 85 lbs 3520

GY Maration
ST235/80R16E inflation 80 lbs 3420

Towmax
ST235/80R16E inflation 80 lbs 3520

Westlake
ST235/80R16E inflation 80 lbs 3520

Greenball
ST235/80R16E inflation 80 lbs 3500

Loadstar
ST235/80R16E Inflation 90 lbs 3500

Trailer King
ST235/80R16E Inflation 80 lbs 3520

Rainier
ST235/80R16E Inflation 80 lbs 3520

Grand Ride
ST235/80R16E Inflation 80 lbs 3520

Arison
ST235/80R16E Inflation 80 lbs 3520

Duro
ST235/80R16E inflation 85 lbs 3520

[Sluggo54]

"The 225/75 R 15 tire of carlisle and Maxis ( and others like Goodyear) have exactly the same maxload at the same loadrange."

In the US, with few exceptions, the federal government specifies that all tires of a specific size and load rating (E, D, whatever) will have the same maximum load rating (3520, 2840, whatever).

[jadatis]

Googled the Carlisle tire in ST 235/80R16 and found 3520lbs AT 85 psi.
Here

While the Maxislist gives for that same tire 3420 lbs AT 80 psi.

When I calculate that from 80 to 85psi then even with the formula America uses still for LT wich would give the lowest max load it would give 3580 lbs max load for carlisle.
So they even are being conservative, so not more maxload then other ST tires of same sise.
The tire below with 235/85R16 has more maximum load at 80 psi , but this is because of the slightly bigger sise.
Have not seen that sise in ST at other brands, can use this for my maxload in compare to speedcode topic because there is exactly the same sise in LT tire.

so the carlisle is not having substantially more maxload then other ST tire as is stated here.

The 225/75 R 15 tire of carlisle and Maxis ( and others like Goodyear) have exactly the same maxload at the same loadrange.

[Lon-Str]

The tires were 225/75/15. There was no damage. I was only traveling about 60 mph and was able to get stopped immediately when I heard the pop. The odds of curbing are very small ( I can see my tires in my mirrors ) but is always a possibility. There was no damage the second time either.

I didn't contact the Mfg. or my dealer as I had gotten nearly three years out of them and would not want them replaced with the same.

The trailer came with Maxxis and that was what I always replaced them with, but my great road trips were slowing down some and I decided to try a cheaper route. For the difference in price I am not that unhappy, and the only reason for me entering the fray at this point is to point out that if you think you are getting Maxxis or Mitchelin quality for Carlisle dollars you could be disappointed.

But I also need to point out that I knew that in the beginning and I did not pay Maxxis or Mitchelin dollars for them.

[Me_Again]

Lon-Str wrote:
As far as the mystery surrounding the Carlisle Radial Trail RH,I do have a dog in that fight now. Didn't know what all the fuss was about until my last trip to west TX. Popped the top off of two of them within about one hundred miles. They have rarely, if ever been over 65 mph and I am very diligent about checking air pressure. They were two years, eight months old. Maybe I've been driving to slow.

What size are they? How did Carlisle do on handling warranty? Did you have trailer damage and did Carlisle cover that? Chris

[Lon-Str]

As far as the mystery surrounding the Carlisle Radial Trail RH,I do have a dog in that fight now. Didn't know what all the fuss was about until my last trip to west TX. Popped the top off of two of them within about one hundred miles. They have rarely, if ever been over 65 mph and I am very diligent about checking air pressure. They were two years, eight months old. Maybe I've been driving to slow.

[Me_Again]

Let face a few facts here. ST tires have inflated ratings out of the box based on the speed restriction(except for the mysterious Carlisle Radial Trail RH). So manufacturers of this type of tires generally tend to say inflate to full sidewall rating.

Now for LT tires. LT tires carry rather conservative ratings that account for a lot of mis-use like overload pickup trucks. LT tires are tested to higher standards from the get go, therefore they do better in a one to one replacement of ST tires within their limits.

My trailer came OEM with the optional Kenda Klever china bomb LT235/85R16E's and the trailer manufacturer placarded the trailer at 65 lbs inflation I believe based on the base ST 15" tires.

In the first year, before a failure, Kenda gave me $110 each to remove and destroy the 5 LT's. I installed Michelin XPS Ribs and ran those at 65 lbs inflation. After a few years I could measure slight more wear on the outer ribs, so I increased inflation to 71 lbs. When I removed them after 40K+ miles and 6.5 years of service, wear was even and around 60-65% tread was left. I installed Bridgestore Duravis R250 and run those at 71 lbs inflation and wear is even across all the tires. Axles weight in at around 10K combined.

Both the Ribs and R250s run cooler than the trucks tires in hot SW weather. which I contribute to the steel ply casing and the rib style tread pattern which creates low rolling resistance. I have recorded a little higher temps on the down wind shaded side in the run from Phoenix to Palms Springs with 40 MPH wind out of the South all day. That run without wind will show the sunny side tires a bit warmer than the shaded side tires. Also the front axle tires run a degree or so lower than the rear axle tires.

Given that I will never have a trailer with ST tires, I do not have a horse in this race of inflation with them. But my advice on them is figure a way to replace them with something more reliable.

Back to the mysterious Radial Trail RH! Is it a better ST tire than others? To soon to tell and not enough in service for a good sample. But the real question is do you want a 3 year tire or a tire that will provide service for 6 or 7 years. And other question is how does Carlisle get around the increase capacity without the speed restriction of 65 MPH? The relationship between weight and speed of tire ratings has a direct reverse effect.

Chris

[SkiSmuggs]

Cummins12V98 wrote:

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.

Aw, shucks! :B

[SkiSmuggs]

I have a lot of respect for Fifth Wheel ST and use their chart. They have an excellent article on 1/2 ton trucks towing fivers.
In regard to tire pressure recommendations, mine came with D rated at 65 psi and I upgraded to E rated that I run at 70 psi, so I in no way am reducing towing safety as I am still above the OEM set up as far as tires go, but I understand and agree with what they are saying when you have the OEM tires.
If my fiver had come with E rated tires, I would run them at 80 psi.

[wandering1]

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.

[JIMNLIN]

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

[Cummins12V98]

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.

[Willcamp4]

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.