GVWR Sticker and Alterations Debate!

[greystroke]

Never saw a post like this. Assuming it is true then "evaluation" is the key. I am sure the mfgr has done his homework and can justify the ratings they put on vehicle. So the Alterer must do the same on their evaluation especially if they want to increase the GVWR.

Make sure your state allows you do this.. For example my truck GVWR is 8800 but I am licensed for a GVW of 9999. The state will look at this if there is an accident. Not sure if other states would honor this.

[TXiceman]

Again, this is what happens when politicians and lawyers write technical laws with little consideration to engineering issues. I am sure you can rerate a trucks GVWR with proper calculations and documentation. But the concept of the change scares the begibbers out of me.

As a point of reference, a pressure vessel above 15 psig and over 10 cu. ft. volume requires an ASME U stamp per the National code, ASME Section VIII. With this stamp there is paper work, for the required calculations, tracking the welders (welders do have to be certified and tested for welding various steel and steel alloys), the material (materials have to be tested and have papers tracing its history) and pressure testing. The final pressure test has to be witnessed and signed by an ASME inspector before the U form is issued for the vessel. All of this is to provide a safe product to the public, otherwise,you would have any small back-woods welder building vessels without regard to the codes.

Now the vessel can be repaired or rerated. The ASME code requires specific procedures be followed and in some cases, a new pressure test and witnessed before the vessel can be legally placed back into service.

I would rather see some kind of specific code requirements for up rating a trucks GVWR. The specific Federal code does not adequately control the parameters of the rerating process. It does leave it open to Bubba's Bait and Axle Shoppee to do the work with little guidance.



Ken

[Beausdog]

I agree...that would be nice....but my argument stands as it's legal to do it, rather than the its not possible or its illegal statements

[Mr_D]

There is a provision, §108(a)(2)(A), in the Vehicle Safety Act that prohibits manufacturers, distributors, dealers and motor vehicle repair businesses from knowingly rendering inoperative in whole or in part any device or element of design installed in accordance with a Federal Motor Vehicle Safety Standard. These parties would be subject to this provision if they were to modify your vehicle’s suspension.However, the provision does not apply to individual owners modifying their own vehicles.”

Notice that the act cited prohibits any BUSINESS from doing the mods, it doesn't prevent any owner from doing the modifications.
But, unless I was a licensed structural engineer, I wouldn't recertify a vehicle either.

[Beausdog]

Originally Posted by Mr_D

Notice that the act cited prohibits any BUSINESS from doing the mods, it doesn't prevent any owner from doing the modifications.
But, unless I was a licensed structural engineer, I wouldn't recertify a vehicle either.

To that which you reference, details air bag removal etc....you would have to look at each one of the mandatory equipment for a waiver.

[Beausdog]

Originally Posted by Beausdog

To that which you reference, details air bag removal etc....you would have to look at each one of the mandatory equipment for a waiver.

And yes, suspension is on that list, but that shows it ust has to be an approved suspension system and not removed or made ineffective

[Beausdog]

In addition, it only applies to vehicles that have not been sold to the end user as clearly stated in the statute. For example, a dealer can not send it out to an aftermarket shop and remove or make inoperative ANY of the safety parts and sell the vehicle which states it complies with all federal safety statutes.

[Franka548]

Beausdog,
The bottom line is that even though you upgrade your tires and add airbags or extra springs, it doesn't necessarily change the gawr or the gvwr. Not saying it can't, just that it doesn't automatically make them higher, there are other things that come into play. And I don't know how many DOT inspections that you have gone through, but each Inspector reads the cfr in a different way for the same code, and what one inspector doesn't even write up, the next insector will red tag you for a violation. I know that usually our pickups don't go through these inspections, but just using them as an example.
Frank

[FastEagle]

Government regulations are a conglomeration of pathways that often lead to a predictable outcome. But, once on a path, a researcher must gather all that apply to a given situation.

In the reference listed below all parts of the basic numbered regulation (certification - 567) must be compared as a whole.

http://www.gpo.gov/fdsys/search/pagedetails.action?browsePath=Title+49%2FSubtitle+ B%2FChapter+V%2FPart+567&granuleId=CFR-2011-title49-vol6-part567&packageId=CFR-2011-title49-vol6&collapse=true&fromBrowse=true&bread=true

Because the reference below is a current document, the information in it is also current. Regardless of how it is used or applied it still reflects the DOT standards as written in the document.

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr;sid=67e9836483620c641d72fce16fb80bb1;rg n=div5;view=text;node=49%3A6.1.2.3.38;idno=49;cc=e cfr

FastEagle

[Mr_D]

FYI:
Our DSDP came with a 12,000# front axle, it was overweight so Newmar had Spartan replace the front axle and steering box with a 14,600# unit.
When done Newmar issued us a new "Modified Vehicle" sticker showing the new axle rating.


With the 275/70 tires we needed 131 psi, but the wheels would only take 120. Michelin issued us a letter on their letterhead allowing the tires to be uprated to the weight rating for 131 psi with only 120 psi in the tires. Ran them that way for about 30,000 miles and 8 years with no trouble.

But, until I changed wheels and tires we couldn't use the full capacity of the axle. Now we can.

[Bobsbeatter]

On an E350 passenger with the 5.4L and either 3.73 or 4.11 ratio, the GCVR is 13,000#.

Conversely, an E450 cutaway with single rear wheels and a 5.4L, the GCWR is 14,050#.

What's the difference you ask? It's not the suspension or frame.
Its the 4.56 gear ratio.

While loading the E350 past it's GVWR might be foolish, towing 1050# past it's 13,000# GCWR might very well be perfectly reasonable. IMO.

[RustyJC]

There is a valid engineering reason that GCWR will vary with axle ratio. In the case you cited, a 4.56 ratio reduces engine and driveline torques from the pinion gear forward required to maintain a given speed under a given load by 10.9% as compared to a 4.11 ratio (4.56 / 4.11). This is why the GCWR is higher with the 4.56 ratio.

Rusty

[Bobsbeatter]

Originally Posted by RustyJC

There is a valid engineering reason that GCWR will vary with axle ratio. In the case you cited, a 4.56 ratio reduces engine and driveline torques from the pinion gear forward required to maintain a given speed under a given load by 10.9% as compared to a 4.11 ratio (4.56 / 4.11). This is why the GCWR is higher with the 4.56 ratio.

Rusty

That may very well be correct. I was thinking that it could simply be that the 4.56 ratio would provide a higher RPM at a given speed and thus more TQ & HP as well as multiplying said TQ by as much as 22% opposed to the 3.73.

Either way, in this case, it would be a fairly straightforward modification to raise the GCWR and substantially improve performance.

[phil57]

A couple of points here. One it does seem that people on a computer are 8'tall and bullet proof. Most folks would have much more of the control we all learned on the play ground when we smarted off to someone and got reminded of our manners by getting smacked in the nose.
Second as manufactures continue to push the limits it will be very difficult to stay at or under GVW and there will be a lot of temptation to ignore the weight,most owners never weigh there rigs. Or they modify their equipment to increase the GVW to haul all the stuff we were told we could haul. In my case I am having issues with my MH and I do weigh mine and I do pay attention to the
weights. Unfortunately manufactures don't. I removed everything from my MH and weighed as I removed. All the continents added up to 850lbs. I am overweight with this on board and full fuel and two passengers. 40'DP
The numbers don't add up and thats all I will say until I meet with the manufacture this week and hash all this out.
My point is if this were a used MH I would be looking for ways to increase the GVW to be safe so whats wrong with having a discussion about what can be done and what can't be done.