Fifth wheel tire pressure recommendations

[Larry]

Inflate to the max on sidewall and forget all the rest.

[drfife]

Originally Posted by Larry

Inflate to the max on sidewall and forget all the rest.

I agree, run your trailer tires at the max cold psi stamped on the sidewall of the tire.

[wingnut60]

Then for my learning give the maximum tonge weight of a 5th wheeler for law.
For travel trailers its 15% and minimum 10 % , I already learned.

jdatis,

There is a law on these tongue/pin weight percentages? Or are you referring to an industry-accepted standard?

Joe

[Cypressloser]

Originally Posted by Timay

I pump mine up to what I think feels good, then hit the road - after 5 - 10 miles I stop and check the temp of the tires...if hot I give some more air, until they run cool.



Tim

Be careful, tire temperature can easily differ by 20 deg between south side and north side

[jadatis]

Originally Posted by wingnut60

Then for my learning give the maximum tonge weight of a 5th wheeler for law.
For travel trailers its 15% and minimum 10 % , I already learned.

jdatis,

There is a law on these tongue/pin weight percentages? Or are you referring to an industry-accepted standard?

Joe

I assumed it to be law that 10 to 15% , but it could be yust industry standard. Already googled for it and 5th wheeler saw 20% coming by.
So if anyone wants to make me wiser on it, its apreciated.
Though I gathered a lot of information in time, about tire-pressure and tires maximum load, I am not a tire-specialist. More a kind of hobby project, that has gotten out of hand a bit.

In Holland, where I live, to law minimum is 1% !!! and maximum 10 %.
That is that low because the axle of trailers is placed more to the front so we are even happy if we get 4% on the towbar. 5 to 7% is adviced for riding quality.
Most tow bars are maximum 50kg/110lbs to 100/220 lbs,so thats a lot less then in America.

To give you an idea , here a picture of the "caravan" as we call it , we had ( now without caravan or camper( motorhome)).

[jadatis]

Originally Posted by Rvmagoo

The unit weight is 9500 lbs, but they not give me hitch weight, tire rating 2880@80psi. Only other info is 5000lbs per axle @ tire size 225/R7515 D rated @ 65psi. Max cargo weight 1441 lbs. will this help with your calculation using the e rated tires. I had no problems with the d rated other than they were weathered and starting to separate so was advised to change before we get a blowout. Your help is greatly appreciated as am a senior on the road.

Then I first added the 1441 lbs cargo weight to the 9500 lbs unit weight, to get 10941 wich I then asume to be the Gross Vehicle Weight Rating ( GWVR)
And combined GAWR ( A for Axle) of 10000 lbs, wich the 4 tires together must be able to bare to law in Europe and most likely also in America.
the 2880 lbs maximum load of the old D-loads is strangely the same as what I found for the E-load ( In Europe its rounded down to the lowest Loadindex-step so 117 /2833 lbs/1285 kg) But I substact even 6 LI steps to give the tire the same save deflection of an LT tire with maximum speed of 99m/160km/h. Seems high , but its only for comparing apples to apples.
Must do some work on the spreadsheet to work this into it , now it gives false warnings , so neglect the Red "these tires have not enaugh maximum load " and the speed warning of max 40 . To see if they are allowed the numbers on the sidewal count, so 4*2833= 11332 lbs so above the 10000 GAWR together.

Then it comes to an advice of 92 psi , wich is not allowed by TRA , so keep it at 90 psi. with this advice maximum reserve with long livetime 6 years if you protect against direct sunlight, because ST probably have less stuf in it to protect the tire against it, read of 3 years maximum livetime given for ST, and that is probably law that you have to keep at, so rules above my advice.

If you ever weigh , try to do it per wheel, and fully loaded.
And apart from the car the hich weight would be nice too.

Then I think it will prove to be much lower , because you had no problems with the old tires. Seached them back at a PDF of Goodyear I have and gave maximum load of 2540 lbs in D load.
So look again if all the data you gave, is right , especially of the tires, old and new . Mayby the sises are a bit different now.

[Ray,IN]

One thing no-one mentioned yet is your rims. You said your trailer came with "D" rated tires and "E" tires were installed. What is the maximum air pressure rating for your rims? If they are aluminum, the max. pressure should be cast into the inside of a web. If they are steel it should be stamped inside the rim, covered by the tire. The lower of that, or tire sidewall max. is the limiting factor.
ST tires do not have a load/lnflation chart, the mfgrs, just say they should be operated at sidewall max. Carlisle Tire goes so far as to state, if their tires are operated at less than sidewall max.the warranty is void. This is because the RMA/Rubber Manufacturers Association, says over 90% of all tire failures are due to under-inflation/overloading.
If you do ever find a load/inflation chart for your tires, remember_ that is the minimum acceptable pressure for the corresponding load.

[SultanGris]

I personally don't know anyone who only goes 65 with trailer tires. Had original tires on my 07 trailer and made it to Nevada in Jan from ND before they started to separate and bubble and I was asking the tire guy if they had better quality higher speed rated ones than just 65 and he said no but everyone down here goes 80 with them including him and doesnt have problems, lol! I replaced with a 10 ply.

[wingedone]

I see them pass me going 70-75 also, while I am tooling along at 65. In fact, I saw a pickup with a popup on I-94 east of Bismarck pass me at about 75mph. Several miles later, I passed him, as he sat on the side of the road with a shredded tire. So sometimes, I see them twice.

I have seen that a couple of times. The other time was a 30' FW

[SultanGris]

Originally Posted by wingedone

I see them pass me going 70-75 also, while I am tooling along at 65. In fact, I saw a pickup with a popup on I-94 east of Bismarck pass me at about 75mph. Several miles later, I passed him, as he sat on the side of the road with a shredded tire. So sometimes, I see them twice.

I have seen that a couple of times. The other time was a 30' FW

That could be from any number of issues and not related to speed. Likely age. I don't usually replace my tires til they start to bubble or go flat. I like getting my money's worth out of them, I have too many trailers to be buying new tires every couple years, haha!

[wingedone]

Believe what you want. I tend to believe what I read on the tire.

[SultanGris]

To each their own, with the evidence I've seen doing it myself and the people I've talked to who exceed the rating I'm not concerned about it. Worst case scenario I have to buy a new tire. I don't buy the cheapest crap tire available though, I'd follow the speed rating a little closer if that's all I could get however.

[wingedone]

Originally Posted by SultanGris

Worst case scenario I have to buy a new tire.

I don't agree. The worse case scenario is it rips off a portion of your trailers siding as is shreds.

The very worse case scenario is someone reads this, believes they can just ignore manufacturers speed ratings on tires, blows one or more tires and careens into a school bus full of kids. Yeah, I think that pretty much covers the worse case scenario.

[SultanGris]

Originally Posted by wingedone

I don't agree. The worse case scenario is it rips off a portion of your trailers siding as is shreds.

The very worse case scenario is someone reads this, believes they can just ignore manufacturers speed ratings on tires, blows one or more tires and careens into a school bus full of kids. Yeah, I think that pretty much covers the worse case scenario.

Good point about the camper and siding but the rest of my trailers are metal and nothing happens when they blow, it certainly doesn't cause your truck to go careening across the road, lol! Have you ever blew a tire on a trailer before? Its pretty uneventful. If you have tandems you better be paying attention or you might be buying a new rim too cause you didn't even notice it blew, haha!