Looking for advice

[Michael W]

So I got around to buying a set of rims for my 26 foot Argosy. They are the Outlaw11 15X7. I just purchased a set of Goodyear Marathions D rated for the rims. My Argosy weighs 4700 lbs per the CAT Scales. Rear axle is 2060 and the front axle is 2640. The Max load per tire is 2540. My Question is if I inflate the tire to max pressure (65 lbs) does this seem a bit much for the rims which have a 1900 lb max. Another Question is the GWVR is 6200 lbs so why did the Certified Automated Truck Scale register the total of 4700 lbs with my truck detached and move away form the scale.

[scottanlily]

Hello michaelw,

Your tires at max pressure can support 10160lbs You do not need to run max pressure in the tires.I said max pressure,because your argosy doesnt weigh anything near that ,nor will you load it near that.Will you? So you have 4 tires to support the load .I would not exceed the wheel rating and they can support 7600lbs. so you are fine ,wont be overloaded at all.The tires can support more than the wheels ,but again not a problem here.I could recommend 45 to 50 psi running pressures ,someone else here may recommend somthing other that they are running on there coach.Max pressure means at max load which as said you wont be near that anyway.Do you mean the gvwr of the trailer or the gross trailer weight ,two different ratings.I believe you mean the load rating of the coach loaded ,with water ,supplies ,propane etc. that would be 6200lbs ,empty is 4700lbs.So loaded you are still in the proper wheel load range.you would have 900lbs to spare before maxed out on the trailers capacity.Just dont get confused on the max air pressure deal .My 60 trdwnd single axle needs 65 psi in each tire as it only has two so more pressure is required.

Scott of scottanlily

[nickcrowhurst]

This link includes a link in one post to the Goodyear load/inflation tables, where you can find the manufacturer's recommended inflation for your maximum load. http://www.airforums.com/forum...-c-load-e-7068-
Nick.

[Michael W]

To Scot of Scottanlilly and Nickcrowhurst, thanks for the quick reply which shows that you guys have been in my same situation before. "Worried and unable to find the answer". Nichcrowhurst, I could not find that link from the post, and it sounds like just what I need. Scot I do feel much better about my setup know that you have examined it. I did look up the meaning of gvwr and its the weight of the vehicle including fluids,fuels,appliances and I guess about everything. Just a guess but I would think it has something to do with the maximum weight that the axles support. So now my only concern is how much pressure to run in the tires. 45 to 50 lbs does seem safe and that is probably what I will use until I find out different. Again, "thanks" for I truely do value your advice and experience...

[Action]

The load on your wheels in a static position will not be the same as in a dynamic (moving) position. When your tire/wheel assembly hits an obstruction (lets say a chuck hole) the pressure or weight demand will go up. It has been stated in this forum that Airstream wheels are rated for 2600 pounds. This may be the reason. Your 1900 pound rateing may be a bit light.

Regardless of the inflation the pressure will be there. Raising or lowering will have little to zero impact on the wheels. The wheels are a solid material. The inflation will have a big impact on the tires.

My next opinion runs in the face of the link that is posted. I believe that the max inflation is the only one that counts. It is for the load being towed. And the trailer tires should always be inflated to the max. And buy tires that will handle the total possible load + 10%. No more than that because the tires would be miss matched to the load. So always inflate my trailer tires to the max cold. And I buy tires that are rated for the total load I will ever encounter + 10%. And my tires are the weakest link (as far as rated load) in the running gear of my trailers. Everything else has a higher load rating. Wheels, bearings, springs, axles.

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[scottanlily]

Hello action,

His tires can support 10160lbs ! The wheels cannot ,they are rated for as he says 1900 lbs ,.Why would you want to max out the inflation pressure Maximum means maximum at max load of 10160lbs is that the loading he will be incuring, no way.your own statement says for the load ,you know it will never be that high.Take into account the pothole impact at 45 mph or more ,the max inflated tire ,hard and solid slamming into said pothole jarring the coach like crazy .the lower pressure rated for the load will ride smoother ,no way to say it wont .His tires are handling the highest load his trailer will ever see .The tires are not going to break the wheels more than likely but the constant thing is that following the proper ratings for wheels ,tires and inflation is very important .Now my trdwnd needs the tires at max pressure because they are at max load ,single axle ,trailer weighs 3150lbs dry ,tires are D range both can handle 4080 lbs.So I am at max load needing max pressure .I would need an E rated tire to go higher on the load.
Anyway its not what I believe but what the numbers say.


Scott

[Action]

Increasing or decreasing the air pressure in the tire wheel assembly does not increase or decrease the load that will be applied to the tire/wheel. The load is the load. The load (weight of the trailer and all that is in it) does not change if the inflation is 10 pounds of air or 65.

Changing the air pressure increases or decreases the ability of the tire to be able to take that load and the ride the tires will give.

In Michael W's example above:
where the trailer actually weighs 4700 #'s and the GVWR is 6200#'s
The wheels are rated for 7600 #'s
And the tires are rated for 10160 #'s at max inflation

My opinion is the tires have too much a weight rating and the wheels are not enough. I would want the opposite rating for wheels and tires. About 10K for the wheels and 7K for tires. Again this is my opinion, the wheels would give long life (as in decades0 because they are not running so close to the limit of the GVWR. (Or total weight rating of the trailer* ~ trailer & all possible contents for now and in the future) And the tires can be run at max inflation and will run cooler and have longer life. The GVWR is the weight limit the manufacture designed the entire vehicle. While the actual weight can and usually is less. It is designed to take that # should the need occur.

A fully inflated tire runs cooler than a tire not fully inflated. And heat is a big reason tires fail internally. So I would much rather buy a tire that is 115% of the max GVWR and inflate it fully than buy a tire that is 150% of GVWR and decrease the air pressure.

Not sure how the above stacks with the tire industry and their stats. I do know how the above works for me in the last 20 years of towing trailers that weigh over 2500 pounds. Again it's just my opinion and experience.

*RV's of any type tend to gain weight as they get older. Rare is the RV that looses weight as it ages.

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[scottanlily]

Hello Action,

i would agree that underinflation overheats tires ,no arguement ,his tires are overrated for the wheels ,yes,he could get 2600lb wheels ,that would closly match the tires ,but still ,I stand by the inflation as I have previously posted ,even with the 2600lbs wheels ,never will he be anywhere near the rated max of the tires .Just because he runs a lower pressure in the tires does not mean they will be under inflated .Max inflation does mean less rolling resistance . the tires can handle much more than the 6200lbs ,but then hes got some cushion there ,not to be max on the tires .Now all this discussion aside ,michael w has the wheels he wants ,which will be fine and the tires will also be fine ,I will say that he could have used load range c and ran the pressure at max ,that would be fine also .The D rated tires are stronger ,rated higher ,tougher construction ,will have a harsher ride at max pressures .they need to run at a lower pressure ,not underinflated .I do agree with your first sentences in your post ,but the proper pressure for the load is what I am talking about .Max pressures are not the only correct pressure ,With my trdwnd they need to be at max ,period . I think my biggest concern would be the harsher ,rougher ride with a heavier rated tire at max inflation . I myself have experienced that when my tires on my 1 ton service truck were inflated to 80psi max and they slammed like crazy over any poor road .They were overinflated for the load .

[Michael W]

When I purchased the rims I did not realize they were 700 #'s less max pressure than the standard airstream rim. As for the tires Sams club could not get the ST C rated marathions. I guess my gut feelings were that the max rating of the rims on my 26 ft. Argosy would be proportionally equal to the max rating of the rims say on a 35 ft Airstream which would be more than twice my weight. I read several forum posts describing problems with the C rated marathions and their decision to move up. I can send the rims back or down grade to a C rated tire if there is a true safety hazzard. I have had my fill of swaying when tractor trailer rigs pass. I have been running regular car tires on this rv thanks to the PO and my inexperience with pulling a rv.

[Action]

Originally Posted by scottanlily

.... I myself have experienced that when my tires on my 1 ton service truck were inflated to 80psi max and they slammed like crazy over any poor road .They were overinflated for the load .

At 80 PSI (max I assume) the load was not matched for the tire capacity. Either the tires are too high a rating for the normal loading or the truck was unloaded and it is anticipated a larger load could be possible.

Same in this case, the tires are rated too much for the load anticipated. 10.0K tire load rating and 4.7K actual load. The load will never get to 8 or 9K. Sure one could pull out some air and run at lower pressure. My experience is that gives the tire opportunity to over heat. Or abnormal tread wear may occur. However most of these tires will crack before the thread wears out. And a less heavy duty tire could have been purchased for assumedily less $.

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[SilverToy]

Hello all -

Reading this thread reminds me that tires, wheels, inflation (max or otherwise) and the like REALLY bring out the passions.....

My I introduce one more variable?

There is a LOT less sidewall flex at max inflation - on every tire, at every load point. Static or moving. Period.

Sidewall flex is a MAJOR contributor to that wiggle when semi's pass - it ain't alway the hitch.

I notice that when I run my TV tires at higher pressures that there is MUCH less wiggle/sway than when I run at max pressures - towing (AS or other) or not. Period.

Sidewall flex is also a big contributor to tire heating. Much more so than cornering, braking and the rest. Every see the side wall on a dragster tire at 'full stress'??

There is also considerable difference from tire to tire as well. Had SteelTex's before - got Michelins. Will go back to the SteelTex's as soon as the M's tread gets to where I can justify it. Just a 'seat 'o the pants' thought there, but still...

Sorry if I threw another wrench into this already hotly discussed thread. Oh well!

Peace

Axel

[jimmickle]

My Argosy weighs 4700 lbs per the CAT Scales. Rear axle is 2060 and the front axle is 2640. The Max load per tire is 2540.

Goodyear's load pressure chart says 1600# at 30 psi and 1880# at 40 PSI. If you were to run 30 psi, you would have sufficient pressure to carry the load you have. At 40 psi, you would have a large safety factor without pounding your trailer to death. My 25 ft 2002 safari weights signifigantly more than your trailer, and the tires run nice and cool at 40 psi. I certainly wouldn't go over 40 psi.

[scottanlily]

Hello jimmickle,

Exactly right, thats the point ,no need to run overpressured than is required.The trailer will be hammered ,there needs to be correct pressure for the given load ,running higher pressure in the tv rear tires do help the wiggle and unstable feeling ,I run higher pressures in mine for the same reason,on the tv ,thats not the same for the trailer however ,again the tires are not underinflated if not at max ,I never said run them at 35 psi or lower or underinflated .The sidewall says max pressure cold 65 psi maximum load of 2040 lbs as in my trdwnd, Max load max pressure given in the same info on the tire for a reason .The tires on my service truck are the correct tires.It is a chevy 1 ton dually commercial truck,they are the front tires .All 6 tires can support more than the truck weighs by far .It carrys my tools and equipment and will never be as heavy as the tires maximum load rating .The tire shop overfilled the rears the first time I had tires on it ,in no time the centers of the tires were going bald ,thats what max pressure did for me,that was some years back ,now I am careful as to the proper inflation pressures.I have had 2 sets of michelins on it in 80.000 miles on the fronts .Michael W do not change your wheels or tires ,they will be fine ,dont get to confused ,what you have will do fine . furthermore with ALL the problems with the marathons,definately stay with the D range tire ,heavier duty ,extra margin load capacity for sure.
No safety hazard to worry about .You should check tire manafacturers websites for there ratings and information ,look at different brands sites also
to help you feel safe in your decision .

Scott

[rseagle]

I bought Outlaw IIs for my F-150 in 2002. When we decided to buy our 2004 CCD, we were pleased that the Airstream also came with Outlaw IIs.