FastEagle wrote: "For single-axle trailers, tires can handle 100% of their load rating. For dual-axle trailers, loads must be reduced by 12%. -Goodyear Tire Company."
Now that's an interesting quote for discussion here.
FastEagle
Interesting how neatly they let the Rv industry off the hook there...
Even the tire industry buys in to the undersizing standard!
Imagine how much better it would be in for both tire manufacturers and consumers if the logic in that sentence were reversed: "For double axle trailers, the TIRE CAPACITY must be INCREASED by 12%"
Which is , ironically, exactly what many folks eventually do.
Not sure this is accurate...I always thought the dual rating meant as in a dually setup????? Why would load rating vary on a vehicle with two axles over a vehicle with one axle. This would effectively mean, for my application, that there are NO G rated tires I can find in 16" that would be suitable for use on my 7000 lb axles...which I have 2 of. Just does not make sense to me.
I read just about everything about RV trailer tires and file all my references. Sometimes I forget where some are stored - LOL. But I found this one.
Not sure this is accurate...I always thought the dual rating meant as in a dually setup????? Why would load rating vary on a vehicle with two axles over a vehicle with one axle. This would effectively mean, for my application, that there are NO G rated tires I can find in 16" that would be suitable for use on my 7000 lb axles...which I have 2 of. Just does not make sense to me.
When a little math is used to see what a safe load capacity would be for LRG G614 tires on two 7000# axles using the recommended 12% reduction by GY you are good to go at 13200# GAW. That’s with all tires aired to 110 psi.
FE
On Edit: Remember, that is a tire manufacturer's recommendation and they are not responsible for setting vehicle tire pressures, the vehicle manufacturer is.
* This post was
edited 03/03/12 04:46pm by FastEagle *
FastEagle wrote: "For single-axle trailers, tires can handle 100% of their load rating. For dual-axle trailers, loads must be reduced by 12%. -Goodyear Tire Company."
Now that's an interesting quote for discussion here.
FastEagle
Interesting how neatly they let the Rv industry off the hook there...
Even the tire industry buys in to the undersizing standard!
Imagine how much better it would be in for both tire manufacturers and consumers if the logic in that sentence were reversed: "For double axle trailers, the TIRE CAPACITY must be INCREASED by 12%"
Which is , ironically, exactly what many folks eventually do.
Not sure this is accurate...I always thought the dual rating meant as in a dually setup????? Why would load rating vary on a vehicle with two axles over a vehicle with one axle. This would effectively mean, for my application, that there are NO G rated tires I can find in 16" that would be suitable for use on my 7000 lb axles...which I have 2 of. Just does not make sense to me.
I read just about everything about RV trailer tires and file all my references. Sometimes I forget where some are stored - LOL. But I found this one.
Calvin, you should get a job with Keystone and solve the issues with most of their larger trailers with GAWR of 6750 and two Marathon's rated to 3420. Have you contacted them about this terrible tire choice? If trailers came OEM with tires better suited to weight and use, then we would see a lot less tire threads. Chris
* This post was
edited 03/03/12 08:26pm by Chris *
My Rig
2001.5 2500 STD CAB AUTO SLT 4x4, CTD 4:10's, Bomb'd to Tow
2005 Cardinal 29WBLX.
The concept of dual load rating for a tire is not new. Light truck tires have one rating for single use and another for dual use.
Quote:
The reduction in load capacity in the above situation is to off-set road camber. (So the theory goes).
FE
It is not unreasonable to make the argument that tandem axle trailers should use the same load limits as shown for dual tire application. Road camber is just one of the contributing factors.
Still looking for the actual Goodyear document that says 12%. The link provided was to a boat trailer page that had a few erronious statements on it. It claimed that GY said 12 % but I didn't quickly find that in the GY documents.
You can learn more if you visit my tire blog RVTireSafety
In my opinion as a QS9000 and ISO/TS 16949 Quality auditor the word "Quality" does not appear to be in the RV industry dictionary.
I need to correct an error I made yesterday interpreting FE's reference to the Federal Motor Vehicle Safety Standards. I said that the total GAWR for a trailer must meet or exceed the GVWR with no allowance for pin or tongue weight. That's only the case for a motorhome:
"S10.1 On motor homes, the sum of the gross axle weight ratings (GAWR) of all axles on the vehicle must not be less than the gross vehicle weight rating (GVWR). S10.2 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. "
Sorry for being anal, but I think this is a really important point. I noticed Tireman had it right in the ensuing posts but still wanted to clear it up.
Not sure this is accurate...I always thought the dual rating meant as in a dually setup????? Why would load rating vary on a vehicle with two axles over a vehicle with one axle. This would effectively mean, for my application, that there are NO G rated tires I can find in 16" that would be suitable for use on my 7000 lb axles...which I have 2 of. Just does not make sense to me.
When a little math is used to see what a safe load capacity would be for LRG G614 tires on two 7000# axles using the recommended 12% reduction by GY you are good to go at 13200# GAW. That’s with all tires aired to 110 psi.
FE
On Edit: Remember, that is a tire manufacturer's recommendation and they are not responsible for setting vehicle tire pressures, the vehicle manufacturer is.
MAN...all well and good, but just how under tired was I with the load range e phony rated Duro tires. That truly is scary. No wonder there are so many tire failures.....
If the trailer is a dual tandam axle unit (8 tires) then the reduction in capacity applies in this case just like a dual wheel axle on a truck. The modern tandam axle trailer (4 tires) with a equilizer bar has no need of its tires load capacity to be derated.
Many boat trailers (and other single and tandam axle trailer types) come with P tires. Fed 571 regs says this about P tires capacity on a trailer:
"When a passenger car tire is installed on a multipurpose passenger vehicle, truck, bus, or trailer, the tire's load rating shall be reduced by dividing by 1.10 before calculating the sum ....(snip).
I can't see Goodyear adding another 12 percent reduction on top of the fed required 10 percent reduction on their tires. They couldn't compete with other tire makers for OEM tire replacemnet, if this was the case.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers
'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 gvwr two slides
JIMNLIN wrote: Fed 571 regs says this about P tires capacity on a trailer:
"When a passenger car tire is installed on a multipurpose passenger vehicle, truck, bus, or trailer, the tire's load rating shall be reduced by dividing by 1.10 before calculating the sum ....(snip).
Sorry if this is redundant...Can/will you post a link to the regs you snip from above?
" Not every mind that wanders is lost. " With apologies toJ.R.R. Tolkien
Sorry if this is redundant...Can/will you post a link to the regs you snip from above?
From: FMCSA 571.110
“S4.2.2.2 When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle.”
That rule is always a normal part of the SOP for vehicle manufacturers and has already been accounted for on the vehicle tire placards whenever applicable.
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