5th wheel tire inflation

[redstickbill]

Is there a general guideline for figuring the correct tire inflation pressures in 5th wheel tires?

[griffinmike]

YES, the correct tire inflation is on the tire sidewalls, beware personal opinions.

[Kirk W]

Discount Tire company's Trailer Tire Facts states that you should always inflate trailer tires to the maximum pressure, as indicated on the tire sidewall. The website of Carlisle Tires states pretty much the same. Tire inflation tables are not common for trailer tires and most tire sellers state pretty much the same. Trailer specific tires are designed differently than those on tow vehicles and should be operated at maximum inflation pressure.

[ronmon]

Goodyear's rv tire inflation chart is published and on the web at "goodyearrvtires.com" and shows reccommended pressures by wheel weights for all their tires they reccommend for rv use.

Ron

[Big Greg]

You will get two views on your question. One is to inflate the tires to their maximum. The second is to inflate the tires based on their load carrying weight using the tire companies inflation chart. I am in the second group.

 

I believe you should first have your fifth wheel AND trucks tires weighed individually to determine how much weight each tire is carrying. This can vary by hundreds of pounds. The Escapees has a Smart Weight program, info here:

https://www.escapees.com/knowledge/smartweigh/program-info

RVSEF (RV Safety and Education Foundation) also has an RV weighing program, info here:

www.rvsafety.com

The RV weighing programs of both these organizations will help you with info on correct tire inflation.

 

Once you know the maximum weight one your RV tires is carrying use the RV tire weight chart to determine the air pressure you should use and add a safety margin. Inflate ALL the RV tires to that air pressure.

 

Here is Goodyears RV tire care info:

Goodyear "RV Tire Maintenance and Inflation Tips" http://www.goodyearrvtires.com/pdfs/RVInflationGde_Sngl_Vnc-1.pdf

 

Here is Goodyears RV tire inflation chart:

Goodyear "Load/Inflation Information" for RV tires http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

 

Our 17.5" H rated tires have a maximum inflation of 125 pounds. I have used both the above organizations over the years to weigh our rig and inflate our fifth wheel tires to 105 pounds based upon the weight the RV's individual tires carry. Greg

[redstickbill]

Thank you everyone. I am aware of motorhome tire pressures and weighing of four corners.

 

Bill B

[Jim Gell]

I did not realize, or I forgot there were two camps on this. Based on the recommendations I chose to follow, I ran at max cold pressure (125 psi for my 17.5 H) only until I was able to get the individual wheels weighed. I have been weighed twice by reputable folks I consider well informed and both suggested lowering pressure as per the Goodyear tables. I now run all 6 tires at the same pressure, about 5 psi over the weight based pressure recommended by Goodyear for the wheel with the most weight. It is better to be a little over than under. The trailer rides a lot smoother at 100 PSI than it did at 125 PSI.

My tires are rated significantly higher than the load they carry.

 

Jim

[redstickbill]

Cathy & Jim,

 

I am a motorhome guy, I was asking for a friend with a 5th wheel. I am in the same camp you are, go by weight.

 

Thanks,

 

Bill

[Ray,IN]

YES, the correct tire inflation is on the tire sidewalls, beware personal opinions.

Pertaining to ST (special trailer) tires, this is absolutely correct. Carlisle tire used to state in their warranty that if sidewall maximum pressure was not used, it voided the warranty.That statement has now been modified to be more vague, perhaps it's the lawyers talking.

To the best of my knowledge, there is only one ST tire mfgr that publishes a load/inflation chart, that is Maxxis.

 

Since the majority of ST tires continually operate very near their maximum weight rating, it's best to inflate to sidewall stated maximum air pressure.

 

My final advice is to thoroughly read CH 4 of this pdf from the Rubber Manufacturers Association, which states:

"

However, never use inflation pressure lower than

specified by the vehicle tire placard, certification

label or owner’s manual. Nor should inflation

pressure exceed the maximum pressure molded on

the tire sidewall"

 

FWIW, every major tire manufacturer is a member of the RMA, and somewhere on their website states the same admonition.

[chirakawa]

Pertaining to ST (special trailer) tires, this is absolutely correct. Carlisle tire used to state in their warranty that if sidewall maximum pressure was not used, it voided the warranty.That statement has now been modified to be more vague, perhaps it's the lawyers talking.

To the best of my knowledge, there is only one ST tire mfgr that publishes a load/inflation chart, that is Maxxis.

 

Since the majority of ST tires continually operate very near their maximum weight rating, it's best to inflate to sidewall stated maximum air pressure.

 

My final advice is to thoroughly read CH 4 of this pdf from the Rubber Manufacturers Association, which states:

"

However, never use inflation pressure lower than

specified by the vehicle tire placard, certification

label or owner’s manual. Nor should inflation

pressure exceed the maximum pressure molded on

the tire sidewall"

 

FWIW, every major tire manufacturer is a member of the RMA, and somewhere on their website states the same admonition.

 

 

Here's the load/inflation table for Goodyear ST tires. http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

 

I would agree with the quote above "However, never use inflation pressure lower than specified by the vehicle tire placard". The vehicle tire placard should be located somewhere on the RV above and in the vicinity of the tires.

 

Here is a webpage for the RV Vehicle Safety and Education Foundation which has links to load/inflation tables for Goodyear, Maxxis, and Towmax ST tires. http://rvsafety.com/tire-inflation-tables/

 

Here is a bulletin posted on Tirerack's website with information from Goodyear. https://www.tirerack.com/images/tires/goodyear/Marathon_Special_Trailer_Applications.pdf Within this bulletin is the following statement "If Goodyear tires, with the ST designation, are used at speeds between 66 and 75 mph(106 km/h and 120 km/h), we recommend the cold inflation pressure be increased by 10psi (70 kPa) above the recommended pressure based on the trailer placard for normal inflation and load conditions."

 

The whole point of my post is, there is no clear and consistent guidance on this issue. It just depends on where you look for information.

[whj469]

There is a sticker on my fiver, near the yellow sticker, that

says 80 PSI. Is that not what I should be using? I thought

that was set for the weight of the fiver?

 

2015 Wildcat 326ck

2011 F250 RWD Longbed CC diesel

[I'mdonewiththis forum]

There is a sticker on my fiver, near the yellow sticker, that

says 80 PSI. Is that not what I should be using? I thought

that was set for the weight of the fiver?

 

2015 Wildcat 326ck

2011 F250 RWD Longbed CC diesel

What is printed on the side of the tire? That is the number I would use.

[remoandiris]

There is a sticker on my fiver, near the yellow sticker, that

says 80 PSI. Is that not what I should be using? I thought

that was set for the weight of the fiver?

 

I went with sticker PSI until I replaced the tires. The dealer I used put a scale under each tire and gave me the recommended pressures for each tire based on those weights.

[Big Greg]

I would set all the tires at the same air pressure based on the tire carrying the heaviest load. I would not air up each tire differently. Manufacturers sticker air pressure is most likely based and the RVs GVWR. When in use the true weight can vary from the GVWR depending on how you load and use the RV. Greg

[D&J]

I think two kinds of tires are being talked about, one is ST tires and the other is 17.5 commercial all position tires. From what I understand the ST ties should be inflated to side wall rated psi but the commercial can be adjusted to axle weight.

 

Denny

[Ray,IN]

Keep in mind those inflation/load charts are showing the minimum air pressure to support that load, not necessarily the optimum.

[chirakawa]

Keep in mind those inflation/load charts are showing the minimum air pressure to support that load, not necessarily the optimum.

 

In your last post, you stated that those charts don't exist. Now, you're telling us what they mean?

[Big Greg]

RayIN, I always add about 10% more that the chart recommends as a safety margin.

Denny, the Goodyear inflation chart also has ST tires listed.

Greg

[chirakawa]

I once owned a 21' Bigfoot travel trailer with tandem 3500 lb. axles. The trailer was equipped with Goodyear Marathon ST 15" D rated tires. Both the axles and the tires were overkill, something not done much in the industry. I put 65 psi in the tires, like the sidewall stated. The trailer rode rough, stiff, and hard. Everything inside was bounced around.

 

On the side of the trailer above the wheel wells was a manufacturer's decal stating to inflate the tires to 35 psi. At 35 psi, the tires were rated at about 1750 lbs., half of the axle rating. I reduced the cold pressure to 35 psi and the trailer performed better, much more to my liking. Never had a tire wear or blowout issue in many thousand miles of traveling.

 

Just one example of my experience, but it convinced me to match tire pressure to load. IMO, that's what those load/pressure tables are for. But, what do tire manufacturers know?

[Ray,IN]

 

In your last post, you stated that those charts don't exist. Now, you're telling us what they mean?

You might want to reread that post.

Your last post is exactly what the Rubber Manufacturers Association states in that quote I included about going by the vehicle mfgrs. tire placard. You indeed have an unique trailer suspension setup, wish all of them did that instead of using the bare minimum to support the trailer.

[chirakawa]

Pertaining to ST (special trailer) tires, this is absolutely correct.

 

To the best of my knowledge, there is only one ST tire mfgr that publishes a load/inflation chart, that is Maxxis.

 

 

 

Keep in mind those inflation/load charts are showing the minimum air pressure to support that load, not necessarily the optimum.

 

These comments were what I was referring to. At first, you said that only Maxxis publishes a chart. Then, when I linked to other mfgs. who do, you went on to tell us what they meant. How can you know what they intended when you didn't even know they existed?

 

I totally agree that my trailer was unique in the industry, I even stated that. However, if the weight to tire inflation levels doesn't warrant lowering the pressure, you obviously would not do so. To state that always inflating ST tires to the maximum pressure as stated on the sidewall "is absolutely correct" is what I'm disagreeing with.

 

IMO, tire pressure should be based on weight load as illustrated in load/inflation tables published by the tire manufacturer's. That's what the placard on the trailer should reflect.