Tires for 5th wheel

[JIMNLIN]

Originally Posted by timetogo

The D rated probably covers the GVWR of the trailer and Keystone saves a buck or two on every unit.

Keystone only needs the tires to get a new empty unit to their dealers.

Actually tires are required by 571 FMVSS safety regs to meet or may exceed the trailer makers axle ratings....not a GVWR.

[cb1000rider]

Originally Posted by JIMNLIN

Actually tires are required by 571 FMVSS safety regs to meet or may exceed the trailer makers axle ratings....not a GVWR.

Are the axle ratings required to meet a vehicles GVWR?

[Tireman9]

Originally Posted by davidki

Tireman9, thanks for the comment, but, saving money isn't what I'd want to do, if I were caring a 9000lb 5th wheel behind me. Saying that does it seem D range tires are a bit low range for the application... the model in question is the Laredo 278SRL, I think the GVWR is actually 10,000 with a ULWR in the 8,000 lb area. Furthermore it seems like Keystone likes to use D rated tires as that is what seems to be on most of the models in that range? Would you consider this a dangerouse idea?

The one trying to save money is the RV company.

Without knowing the size of the tires, I can't provide an opinion the advisability of using those tires. 'Load Range-D" is not enough info,
IMO they probably just meet the GAWR but there may be no margin and may in fact be overloaded if the actual load is not exactly balanced side to side 50/50.

[jkn1946]

It seems that trailer and fifth wheel are being used interchangeably. We have a fifth wheel. It will take some time to go through the recommendations and I really appreciate your advice. Safety is of the utmost importance.


Sent from my iPhone using iRV2 - RV Forum

2015 F350 diesel 4x4 Lariat
Northwood Arctic Fox 5Wheel 29-5T

[FastEagle]

Originally Posted by cb1000rider

Are the axle ratings required to meet a vehicles GVWR?

The FMVSS also requires the trailer manufacturer to establish a published hitch/pin weight. That established pin weight when added to the total GAWR must equal or exceed the trailer's GVWR.

FastEagle

[JIMNLIN]

Originally Posted by cb1000rider

Are the axle ratings required to meet a vehicles GVWR?

Just to add to FastEagles answer from the 571 FMVSS; (snipped)

571.110/.120
On RV trailers, the sum of the GAWRs of all axles on the vehicle plus the vehicle manufacturer's recommended tongue weight must not be less than the GVWR. If tongue weight is specified as a range, the minimum value must be used.**

[Tireman9]

Originally Posted by jkn1946

It seems that trailer and fifth wheel are being used interchangeably. We have a fifth wheel. It will take some time to go through the recommendations and I really appreciate your advice. Safety is of the utmost importance.
Sent from my iPhone using iRV2 - RV Forum
2015 F350 diesel 4x4 Lariat
Northwood Arctic Fox 5Wheel 29-5T

There are numerous posts advising the same thing. I know I have made posts saying the same thing so often I am considering just pasting a form letter reply.

1. Load the TT, 5th wheel or MH with water, propane, food, clothes & people as you would normally have to travel
2. Get on a truck scale and learn the actual laod on each tire position. There are worksheets available to help with that process. If you can't do that, use the actual load on each axle and assume one end carries 53% of the load
3. Motorhomes can use the 53% number to establish their minimum inflation and then add 10% to establish their cold inflation
4. Towables and this includes 5th wheels as they are "towed" also. need to confirm no tire is loaded more than the 53% number. In fact they should adjust inflation up to result in about a 15% margin over the 53% figure.
5. Multi axle trailers should run the inflation on the tire sidewall to lower the Interply Shear.
6 All RVs motorized or towable should run TPMS
7 TPMS should have "rapid air loss" feature to warn when pressure is lost from the higher "HOT inflation" not just after loosing air to below the level needed to carry the 53% figure.
8 All need to run no faster than the speed rating molded on the tire. If there is no speed rating on the tire then the default would be 65 for ST type tires and 75 for LT and TBR sizes.
9 All tires on each axle should carry the same cold inflation.
10 Cold inflation means the tire is at ambient and not warmed by the Sun or having been driven more than 2 miles.

If you want to learn more about tires, valves and TPM I suggest you read my RVTireSafety blog where the above points are covered in detail.

[jkn1946]

Thank you I will look for your blog. We have weighed twice. The first time we got a weight for each set of axels and the second only a total. I appreciate all the info. Jeri


Sent from my iPhone using iRV2 - RV Forum

2015 F350 diesel 4x4 Lariat
Northwood Arctic Fox 5Wheel 29-5T

[Dtwallace]

Originally Posted by Technobody

I would stick to the "ST" tires they are superior to any LT. The ST stands for Special Tire and have been designed specifically for RV Trailers. It's about the strength of the sidewall. Also always go up a load class Use G as an example rather than say E because they are more readily available.
Your take the load range of your four tires and it should equal the weight of your trailer.

Sir,
No the ST is not a better tire, but it does ride softer. However, I think the goal here is reliability.
LT's will aways handle the weight better due to heavier side wall construction, where you can always run your maximum air pressures keeping the tire running cooler in all weather conditions.

[JIMNLIN]

Originally Posted by Dtwallace

Sir,
No the ST is not a better tire, but it does ride softer. However, I think the goal here is reliability.
LT's will aways handle the weight better due to heavier side wall construction, where you can always run your maximum air pressures keeping the tire running cooler in all weather conditions.

Good points.
I would add a ST tire is made for a trailer position only vs the LT which can be used in a trailer position/steer position or drive position. In Europe the LT would be marketed as a all position tire.
At one time Carlisle advertised the ST tire sidewall stiffness as a compromise between the P and LT tire.

[Tireman9]

Originally Posted by Dtwallace

Sir,
No the ST is not a better tire, but it does ride softer. However, I think the goal here is reliability.
LT's will aways handle the weight better due to heavier side wall construction, where you can always run your maximum air pressures keeping the tire running cooler in all weather conditions.

Interesting idea that say an LT235/85R16 LR E with a load carrying capacity of 3042# is some how able to handle the load of the trailer better than an ST235/85R16 LR-E with a load capacity of 3640#.

The load placed on the tires would of course be the same as the trailer doesn't know what kind of tire is under it.

Somehow my Degree in Mechanical Engineering and 40 years experience as a tire design and quality engineer led me to believe that 3,640 was greater than 3,042.

(end of snide come-back)

[FastEagle]

Replacement tires for RV trailer axles. It’s a complicated subject in most forums and it shouldn’t be. The procedures are simple and well established when seeking information from authorized retailers familiar with your tire needs..

This is a standard and very basic statement about replacement tires.

Never choose a smaller size than those that came with the vehicle. Tires should always be replaced with the same size designation - or approved options - as recommended by the vehicle manufacturer or authorized dealer. (To me, an authorized dealer would be one that stocks the tires in question and has experienced personnel familiar with your tire fitments).

There are some very experienced posters in these tire postings. They pretty much agree that replacement tires should have 15-25% reserve load capacity above the trailer’s total GAWR.

A common misconception is “replacement tires only need enough load capacity to equal the axle’s ratings”. Who said that, and where did it get started? The FMVSS says that, problem is, they are saying it to the vehicle manufacturer (ONLY!). So it has nothing to do with replacement tires because the vehicle’s Original Equipment tires set the standard for that vehicle. When reading all of the FMVSS for manufacturer tire selections and fitments that will become clear to the reader. But, that’s time consuming and not always productive. So look at some industry standards written by tire manufacturers. They are clear and apply. Here is a simple one.

http://us.coopertire.com/Tire-Safety/Replacement-Tire-Guide/Load-Capacity.aspx


FastEagle

[Lac]

Originally Posted by SkiSmuggs

You don't say what size or load range. I replaced my Tow Max load range D tires with Maxxis load range E from Amazon and had them installed by a local tire shop. 8,000 miles with no issues. Maxxis tires are not made in China.

Your right they are made in Thailand...

"Answer directly from Maxxis…

I appreciate your comments and will not give you the “canned” response. We don’t do that. Yes, the Maxxis M8008 ST Radial trailer tires are indeed manufactured in our state-of-the-art factory in Thailand (only).

On a side note, while I do understand your position on China produced products, that is certainly not true across the board. Maxxis maintains several plants in China as well as Thailand, Taiwan and Vietnam. A portion of our Auto and Light Truck product offering is produced in China, but not our ST Radial. I can assure you the same high level of quality workmanship and materials is maintained on China produced tires, as that of our other factories. Some Chinese goods, maybe deservingly so, has gotten a bad rap in recent years. However, not all goods produced in China are of inferior quality. Maxxis is a fine example of that.
I hope this is helpful but feel free to email me directly at the address below if you have other questions. Thanks for your email and interest in Maxxis Tires. "

[Dasmoeturhead]

My trailer came with 17.5'' wheels, wrapped in Good Year G114's load range H. I love these tires, but I'm sure when it comes time to replace them I won't be so happy. The way they ride though, I've already decided I will buy new G114's when the time comes. They show no wear after 9,000 miles so far.