Air Bags

I have owned pull behind trailers all my life.  In 2015 I upgraded my tow vehicle to a Duramax 2500.  I did this in anticipation of my wife being able to retire and to be able to step up to a 5th wheel.
I know that by getting only a 2500 instead of a 3500, I would suffer a bit in how large of a 5th wheel I could get.  I am just now starting to look at the available options as far as size, etc. 

I have a question about air bags however.  Are they designed only to smooth out the ride? 

They will raise the rear end back up once you put all the weight in the bed.  This can be helpful mainly at night because you won't be blinding on coming traffic.  Sure someone else will have another reason but I added them to my F-350 just so I could keep everything level with all the weight.

Air bags will level the truck and will soften the ride some.  It WILL NOT change the truck payload, GVWR or rear axle capacity.

I have a question about air bags however.  Are they designed only to smooth out the ride? 

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  Bags accomplish several things and may or may not smooth out a ride. In certain conditions bags can raise the trucks rear till its just touching or a gap in the aux upper over load springs. This can cause a very bone jarring ride.

Adding air bags will increase the truck rear suspension ability to carry more load or level the existing load.

GM 2500 trucks ,as most 3/4 ton trucks, are good for around 3000 lbs in the bed before exceeding the trucks rear spring pack/17" tire or wheel ratings.

If your 2500 GM has the 18" or 20" tire and wheel option then bags will allow the rear suspension to carry about the same weight as its twin 3500 SRW truck.  If your 2500 has the upgraded tires and wheels then the rear spring pack is the only major difference in a 2500 vs 3500 SRW.
GM rates the 2500 ar 6200 rawr vs 7050 rawr for the SRW truck = around 800 lb load difference.
Actual scaled front and rear axle weights will tell you how much load your track may carry in the bed.

 

longhaul said:

  Bags accomplish several things and may or may not smooth out a ride. In certain conditions bags can raise the trucks rear till its just touching or a gap in the aux upper over load springs. This can cause a very bone jarring ride.

Adding air bags will increase the truck rear suspension ability to carry more load or level the existing load.

GM 2500 trucks ,as most 3/4 ton trucks, are good for around 3000 lbs in the bed before exceeding the trucks rear spring pack/17" tire or wheel ratings.

If your 2500 GM has the 18" or 20" tire and wheel option then bags will allow the rear suspension to carry about the same weight as its twin 3500 SRW truck.  If your 2500 has the upgraded tires and wheels then the rear spring pack is the only major difference in a 2500 vs 3500 SRW.
GM rates the 2500 ar 6200 rawr vs 7050 rawr for the SRW truck = around 800 lb load difference.
Actual scaled front and rear axle weights will tell you how much load your track may carry in the bed.

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AIRBAGS DO NOT INCREASE LOAD CAPACITY ON A LIGHT DUTY VEHICLE the bags may be rated for 3000 or 5000 lbs but adding bags doesnt change the factory rating PERIOD - you may be able to put more weight in the box but it doesnt change the rating - i have a 3500 chevy cargo capacity  rating as per yellow decal is 3875 i have air bags the rating is still 3875 but my 5er is heavy so the bags even out the truck putting the weight more evenly distributed bringing the nose down and the ass up.

I don't want to get into the debate of "factory rating" or GVWR vs the air bad rating, but here's something  to keep in mind:

Strengthening the suspension with an air (or any other type) spring doesn't change the tire load capacity, nor does it alter the mechanical strength of the axle and wheel hubs. The old adage "A chain is only as strong as it weakest link" applies here.

I was looking for GMC 3500 SRW with the highest payload numbers I could get.  I found a 2016 GMC Denali diesel with yellow payload tag of 3722 and ask what about lighter gas engine would that give me more payload.  A little research we found that GMC 3500 gas engines had a lower GVWR of 10,900 and were not available in the 11,500 GVWR like the diesel.  I checked Ford and found the same thing, lower GVWR for gas engines in the F350 lineup.  Dealer called their support network and the guy told us that GMC frame/suspension/brakes would NOT support the higher payloads with a gas engine with a 11,500 GVWR. 

steveblonde said:

AIRBAGS DO NOT INCREASE LOAD CAPACITY ON A LIGHT DUTY VEHICLE the bags may be rated for 3000 or 5000 lbs but adding bags doesnt change the factory rating PERIOD - you may be able to put more weight in the box but it doesnt change the rating - i have a 3500 chevy cargo capacity  rating as per yellow decal is 3875 i have air bags the rating is still 3875 but my 5er is heavy so the bags even out the truck putting the weight more evenly distributed bringing the nose down and the ass up.

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We will have to agree to disagree.
  Bags can be and are used to help any suspension carry a bigger loads or level a load.  But at least you you are right about bags not changing a GAWR number.
We use them on on our trucks in commercial service as a saggy truck attracts dot attention quick when rolling through a scale house. I had them on all my one ton DRW trucks to keep the load level.

Adding air bags doesn't change the official GVWR or axle (GAWR) rating of the vehicle - only the chassis manufacturer or a qualified engineering firm can issue a credible statement that would be legally acceptable. As to what practical effect the air bags may have on load carrying, that can be anywhere from nothing to substantial, depending on the other components involved.

I have always wonder when people find out about ignoring GVWR and going with axle ratings.

On the Federal Mandated Door Sticker has three ratings GVWR , Front Axle, Rear Axle so why would you ignore one of the ratings and declare you shouldn't ever exceed the other two?

On the box for my Firestone Bags is states that they do NOT change the weight ratings of your truck and warns exceeding them so not the air bags.

With the manufactures want to be "Best in Class Payload" why don't they use axle ratings instead of the lower GVWR?

I know 18 wheelers use axle ratings but they can also install different axles with higher ratings and that will increase their DOT ratings where replacing axles on class 2,3,4 trucks doesn't.

When I ask for reference to that standard people just point me toward a forum post.  Where is written to ignore GVWR and use GAWR?

I always just wrote it off as excuse to justify exceeding the limits on the truck not based in fact.

On the Federal Mandated Door Sticker has three ratings GVWR , Front Axle, Rear Axle so why would you ignore one of the ratings and declare you shouldn't ever exceed the other two?

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Where is written to ignore GVWR and use GAWR?

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Not sure where you have see this, but you are right. Where they apply, legally none of those three can be exceeded. However, "legal" or not depends on the vehicle and its usage, and most of the weight limit laws apply to commercial use only. So private RVers get to make value judgments and may possibly ignore the ratings. If they judge badly and perhaps cause an accident as a result, their [poor] judgment might become subject of a civil law suit, but that's a rather different matter.

When a truck company changes an axle, they have professional chassis mechanics and documentation from the axle manufacturer that certifies the new axle's rating. Firestone cannot certify any changes to the GAWR or GVWR of a vehicle they've never seen and modified by guy in his back yard, so they wisely refuse to provide any certification..

Of course!  But the ONLY way to install them is to remove a couple of the stock springs, so the bags will carry the weight.  Unfortunately no one else will tell you this!

If you leave all the springs on the truck the bags won't be made to do any work, until you get something really heavy in the truck.

And the ONLY way (again NO ONE else will tell you this!!!) to put air ride on your truck is to install a leveler valve between the differential cover and a cross member on the frame of the truck. That way, no matter what the load is the bags will maintain the ride height you set on the leveler valve!!!  Here's one designed for a semi truck that will work perfectly for you.  I built a rat rod pickup with one of these on it.............. http://www.ebay.com/itm/Neway-90054007-Height-Control-Leveling-Valve-replacement-/271841423733?hash=item3f4b02f175:g:zNYAAOSwNSxVMRNf&vxp=mtr

All you do is run a hose from the air tank, to the leveler valve and then to the air bags.  And be sure to put a air pressure switch on your air tank so it maintains pressure of 150 pounds.

JC Whitney sells the basic air ride kit about as cheap as anyone out there.  I priced one for my 200 Dodge that was $250. Then you need a Viar compressor, the tank, the leveler valve, the pressure switch and some fittings.

Gary [ RVer Emeritus] said:

I don't want to get into the debate of "factory rating" or GVWR vs the air bad rating, but here's something  to keep in mind:

Strengthening the suspension with an air (or any other type) spring doesn't change the tire load capacity, nor does it alter the mechanical strength of the axle and wheel hubs. The old adage "A chain is only as strong as it weakest link" applies here.

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WRONG!!!  Airbags WILL increase the cargo capacity. The question IS, is it is a LEGAL cargo capacity?!!!  Probably not.

rodbuilder said:

WRONG!!!  Airbags WILL increase the cargo capacity. The question IS, is it is a LEGAL cargo capacity?!!!  Probably not.

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WRONG!!!!!

AIR BAGS DO NOT INCREASE CARGO CAPACITY.  They may keep it level, but they do NOT change tire weight ratings, braking capacity, axle capacity, transmission cooling or frame strength. 

The question is are you a law abiding citizen or a careless daredevil, willing to put other people's lives at risk.

Airbags WILL increase the cargo capacity. The question IS, is it is a LEGAL cargo capacity?!!!  Probably not.

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Correct.
  Air bags/higher rated springs and a host of other aftermarket suspension products WILL increase the suspension ability to carry more load which is the point being made. No one has said it increases a gawr or a gvwr number.


All commercial or non commercial vehicles on the road come under axle/tire load limits.

Some seem obsessed with a GVWR number which can be any number the vehicle maker wants up to the sum of the GAWRs.  Points to think about;
GVWR is not a drop dead number. In fact dot does not use a trucks gvwr for how much load it can carry....nor is it used in any civil  court case for a overload condition.

In some cases our newer trucks with high gvwr based payloads are over loading the trucks rear axle/tires when placed in the bed.  Fords F150 with a 3200 lb gvwr based payload is a good example. Their is no F150 that can carry 3200 lbs in the bed such as our truck campers/GN hitch weight or 5th wheel pin weights/bumper pull trailers/load of RR ties from the farm store/etc.

Another example of the fallacy of using a gvwr as  some sort of holy grail is a Ford F350 SRW trucks which several can come with a 10000 gvwr or a 11200 gvwr....one being a crew cab 6.7 diesel 4x4 172" wheelbase 5600 fawr and 6290 rawr. These truck are the same truck ....just a different gvwr. Ford fleet specs says one comes with a 2200 lb gvwr payload and the other a 3400 lb payload.

Brakes ?? Their a function of the gawrs....which is another reason dot doesn't enforce a truck makers gvwr. 
...anyways lots of blather about what air bags do

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All vehicles on the road........We may safely/legally carry weight up to the vehicle gawrs/tire load rating. Example in the one ton DRW pulling a heavy GN trailer with a declared 35k-40k gcw we see and drive next to every day. Some with or without a dot number. 
Were safe in doing so and pose no danger to others on the road. If you feel unsafe driving around us either speed up or slow down and get away from us or simply don't drive on the road with us as just about 100 percent of us operating with a dot # are operating above the mfg gvwr or up to the sum of the axle/tire load ratings.

 

I have hard time believing that on the silver Federal Mandated Sticker that has my axle ratings also has a GVWR and out three ratings it fine to ignore one them and not the other two.  DOT and Feds mandating that sticker why would put GVWR and just ignore it, just doesn't make sense.

My GVWR on my truck is 11,500 and last weighting I was at 11,380 with almost 1200 lbs of additional axle capacity.  So are saying I can over 12,500 GVWR maxing out my axles. 

You try to compare a F150 with 18 wheeler and there don't follow the same rules.  Commercial trucks don't have a GVWR but payload is determined by axle ratings.  The correct statement would be all vehicles that don't have a GVWR go by Axle Ratings but vehicles that have a Federally Mandated GVWR should not exceed any of the ratings and that's from a DOT representative.

The yellow tag Payload is way to compare the capacity of the trucks on the car lot and that sticker is only valid the day it left the factory.  That payload weight is scale weight minus GVWR.

If true that I can go over 1200 over my GVWR why wouldn't truck manufactures that want to "Best In Class Payload" why would they use axle ratings.

In a court case ever state has a law on the books that your must operated a vehicles on public road within manufacture specs.  I guess you would have to determined in GVWR/payload is a factory spec or not.

When you look up the definition of GVWR on DOT or other Federal site states the max you truck can weight but I can't find anywhere is says to ignore GVWR that it really doesn't count and can be exceed by axle rates.  "Code of Federal Regulations, Title 49, Section 571.3 Definitions" (PDF). USA. Retrieved 2012-03-03.


I guess we have to disagree..... 

air bags do not increase capacity period any one who tells you different will also tell you a pound of butter weights more than a pound of manure
a capacity rating is just that a rating unless you change physical components all your doing is redistributing

longhaul

I see you have a DOT number on your truck and the state transportation officer I talk to said that's loop hole in the regs.  If you have DOT they go by axle ratings but without DOT number it's which every rating they exceed first GRWR or GAWR.  He also said their was a rule change in the pipeline to close that loop hole on trucks with GVWR and didn't know the status of it.

CWSWine said:

longhaul

I see you have a DOT number on your truck and the state transportation officer I talk to said that's loop hole in the regs.  If you have DOT they go by axle ratings but without DOT number it's which every rating they exceed first GRWR or GAWR.  He also said their was a rule change in the pipeline to close that loop hole on trucks with GVWR and didn't know the status of it.

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X2

CWSWine said:

longhaul

I see you have a DOT number on your truck and the state transportation officer I talk to said that's loop hole in the regs.  If you have DOT they go by axle ratings but without DOT number it's which every rating they exceed first GRWR or GAWR.  He also said their was a rule change in the pipeline to close that loop hole on trucks with GVWR and didn't know the status of it.

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You didn't see a dot number on my current trucks. But I have had several in commercial service some years ago but I'm retired from all that.

First off there is no state that uses the trucks GVWR for a overload condition nor do they use the tire placard payload numbers. There are no regs on the books stating so. Down the road feds may make a rule change requiring GVWR to be enforced by the states.....but not now.

All trucks on the road come under interstate axle/tire regulations...even RVs.

FHWA... Questions and Answers about Vehicle Size and Weight
     
        23 CFR 658.5 Definitions

Q.. What are recreational vehicles?
They are generally a vehicular-type unit primarily designed as temporary living quarters for recreational, camping, travel, or seasonal use that either has its own motive power or is mounted on, or towed by, another vehicle. (From ANSI)

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Q.. Are recreational vehicles subject to Federal size and reasonable access requirements?
No, because they are not commercial motor vehicles.

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Q.. Are recreational vehicles subject to Interstate axle weight limits?
Yes.

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Q.. Are recreational vehicles required to stop at State scale sites?
Each State may set its own requirements.

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    If a non commercial vehicle owners truck/trailer is ever weighed for a over weight violation they weigh the trucks steer and drive axles and trailer axles. There is no gross weight or gvwr or gvw check.....unless your state has one for registration purposes.
    My state as others has no registered weight....  were simply weighed for being over a axle/tire load rating just as commercial trucks are.