Max front axle + max rear axle = Gross GVWR?

[sportcoupe]

My 2022 Vegas is on a E350 chassis. The data plate states 5000 lbs front and 8500 lbs rear max weights. Gross GVWR is stated 12500 lbs.

Old school math:
5000 + 8500 = 13500

Why is the E350 chassis gross GVWR downrated by 1000 lbs?

I ask because another member has a E450 and their front/rear add up to 14600 lbs and their gross GVWR is 14500 lbs, pretty close to axle maximums.

[EA37TS]

Because other things are taken into consideration when computing GVWR. It is not based on axle weights alone.

I posted the government’s requirements for GVWR and GCWR on another thread. Use the search feature to locate the document.

[sportcoupe]

Originally Posted by EA37TS

Because other things are taken into consideration when computing GVWR. It is not based on axle weights alone.

I posted the government’s requirements for GVWR and GCWR on another thread. Use the search feature to locate the document.

Well, if you yourself made a thread on GVWR requirements, it doesn't come up in a search.

If you posted a reply with these requirements, I couldn't find that either.

I'm not aware of a document folder in this forum either.

I'd like to know the "other things" taken into consideration. These GVWR are from Ford on a stripped chassis, not from Thor completion build.

My E350 is reduced from axle maximums and a E450 is not. Strange.

[Chance]

I believe regulations set an upper limit, but manufacturers can reduce GVWR or GCWR to suit their needs.

An example is E-350 with Single Rear Wheels (SRW) which had GVWR increased to 10,050 pounds to fall under Class 3, whereas years earlier GVWR was just under 10,000 pounds and thus fell under Class 2b.

Regulations seem complex since they involve safety, emissions, etc. I doubt it is a marketing coincidence that many chassis are rated at +/- 9,900 pounds and others just above 10,000 pounds.

[EA37TS]

Originally Posted by sportcoupe

Well, if you yourself made a thread on GVWR requirements, it doesn't come up in a search.

If you posted a reply with these requirements, I couldn't find that either.

I'm not aware of a document folder in this forum either.

I'd like to know the "other things" taken into consideration. These GVWR are from Ford on a stripped chassis, not from Thor completion build.

My E350 is reduced from axle maximums and a E450 is not. Strange.

Posted in a thread on weighting motorhomes and the yellow labels. It’s there.

Took one search and 10 seconds

https://www.thorforums.com/forums/sh...2&postcount=21

[Chance]

sportcoupe, if asking about why or how chassis ratings are determined by chassis manufacturer instead of your cargo carrying capacity by RV manufacturer, you can do a Google search and find many articles similar to one below. I doubt you will find the exact answer you are probably looking for in case of your motorhome.


https://www.ntea.com/NTEA/Member_ben...k_trucks1.aspx

Originally Posted by NTEA ARTICLE

There’s a common misconception that a truck’s GVWR is determined by adding gross axle weight ratings (GAWRs) together for all axles. Although this was a common way of calculating GVWR many years ago, it’s no longer an accurate method. The chassis manufacturer task of establishing a vehicle GVWR is much more difficult today due to advancement of safety system standards and how vehicles meet these requirements. This is why many trucks have a GVWR much lower than the combined axle ratings. It’s not uncommon for a truck with a GVWR of 19,500 pounds to have a front axle rated at 7,500 pounds and a rear axle rated at 14,700 pounds. Safety standards that apply to braking, vehicle stability, and chassis manufacturer internal standards for durability, dynamic stability and handling can restrict GVWR even though the sum of the axle ratings exceeds 22,000 pounds. In this instance, the OEM set the GVWR at 19,500 pounds based on test results and vehicle dynamic performance to ensure a safe, reliable truck.

[sportcoupe]

Originally Posted by EA37TS

Posted in a thread on weighting motorhomes and the yellow labels. It’s there.

Took one search and 10 seconds

https://www.thorforums.com/forums/sh...2&postcount=21

Sure you can find a post you made in ten seconds.

I used key words from your statement below, as I didn't know what I was looking for. I came up empty.

• government
• requirements
• GVWR

"I posted the government’s requirements for GVWR and GCWR on another thread. Use the search feature to locate the document."

[sportcoupe]

Originally Posted by Chance

sportcoupe, if asking about why or how chassis ratings are determined by chassis manufacturer instead of your cargo carrying capacity by RV manufacturer, you can do a Google search and find many articles similar to one below. I doubt you will find the exact answer you are probably looking for in case of your motorhome.


https://www.ntea.com/NTEA/Member_ben...k_trucks1.aspx

Sort of.

I was asking why a 2019 E450 GVWR is a result of adding the max axle weights together but a 2022 E350 GVWR is calculated at a reduced the sum of the added axle weights by 1000 lbs. Seems strange.

I doubt 2019 is considered "many years ago" by the NTEA article.

Has no one noticed this before?

[EA37TS]

Originally Posted by sportcoupe

Sort of.

I was asking why a 2019 E450 GVWR is a result of adding the max axle weights together but a 2022 E350 GVWR is calculated at a reduced the sum of the added axle weights by 1000 lbs. Seems strange.

I doubt 2019 is considered "many years ago" by the NTEA article.

Has no one noticed this before?

There are things not related to axles that are contribute to GVWR. Metals, brakes, weld points and other suspension items to name a few.

Call Ford and ask them for the specifics.

[Chance]

Originally Posted by sportcoupe

Sort of.

I was asking why a 2019 E450 GVWR is a result of adding the max axle weights together but a 2022 E350 GVWR is calculated at a reduced the sum of the added axle weights by 1000 lbs. Seems strange.

I doubt 2019 is considered "many years ago" by the NTEA article.

Has no one noticed this before?

Yes, of course it has been noticed, and discussed many times by many including me as it relates to the E-350 (particularly the SRW E-350).

Please note it has nothing (or very little) to do with 2019 versus 2022 Model Year ratings. The E-350 and E-450 have been essentially the same for the most part for at least a decade (probably since suspension and brakes upgraded in 2008).

The E-350 still comes in various GVWR and GCWR even when comparing DRW. There is at least an 11,500 pound GVWR option, and some have a much lower GCWR well below 18,500 pounds. However, I would guess most RV manufacturers get a significant price discount for the RV package which includes popular features. I’d bet 12,500 GVWR and 18,500 GCWR is most popular on E-350 for RV use.

If we look at F-350 pickup specs in greater detail, we can see that axles themselves can be common over a wide range of GVWR for both 2WD and 4X4.



P.S. — At one time Ford offered SRW E-350 stripped chassis under 10,000-pound GVWR, but was discontinued. I’m certain Ford could upgrade rating to 11,000 pounds or greater today if need for smaller-than Axis/Vegas Class As materialize.
.

[ducksface]

Ok...
Now what?
I don't get the comparing things you don't own to things you do own, thing.

[EA37TS]

Originally Posted by ducksface

Ok...
Now what?
I don't get the comparing things you don't own to things you do own, thing.

More than likely they feel they got cheated or the E350 should be able to carry an additional 1000 pounds. That is usually why these threads get started over and over again

Sorry, the GVWR is what it is calculated by Ford and slid on the various stripped chassis models. The E350 is not an E450 and has different specs and limitations.

[sportcoupe]

Originally Posted by ducksface

Ok...
Now what?
I don't get the comparing things you don't own to things you do own, thing.

That's the whole purpose of these forums.

[sportcoupe]

Originally Posted by Chance

The E-350 and E-450 have been essentially the same for the most part for at least a decade (probably since suspension and brakes upgraded in 2008).

Originally Posted by EA37TS

Sorry, the GVWR is what it is calculated by Ford and slid on the various stripped chassis models. The E350 is not an E450 and has different specs and limitations.

Well there is disagreement in this thread on E350 and E450 chassis. Both by respected members.

I understand GVWR is calculated by Ford and not Thor. I don't get why it's calculated differently between the different striped chassis, at least from the very small sample size of two

Probably two different engineering groups did the calculations

.

[16ACE27]

Originally Posted by sportcoupe

Well there is disagreement in this thread on E350 and E450 chassis. Both by respected members.

I understand GVWR is calculated by Ford and not Thor. I don't get why it's calculated differently between the different striped chassis, at least from the very small sample size of two

Probably two different engineering groups did the calculations

.

Chance did NOT mean that the E350 and the E450 were the same: He meant the two lines; the E350 line, and the E450 line have not changed significantly over the years.

[Sappy2]

This is done to allow shifting of weight to front or rear axle, and still be under the overall GVWR rating. Look at it this way, so long as you stay under the rated GVWR, you can max load the front axle, or the max load the rear axle, but not both. And it will also depend on the configuration that was ordered by the motorhome manufacturer for motorhome final stage finished product (Ford has limits set and packages specific to that vocation / industry). Ford does the same with medium truck and other commercial vehicles, you can have a 21K rear gawr, and a 12K front gawr (both total 33K), but the overall gvwr will be 25,999 (for certain market needs). So, in this example you can load the front axle to 10K, or the rear to 21K, but never both in a way that will exceed the gvwr rating of 25,999 that is stated on the certification label. Now I know that some folks are gonna disagree, but that is how it works with axle capability and overall gvwr listed on cert labels with Ford.

[Chance]

Originally Posted by 16ACE27

Chance did NOT mean that the E350 and the E450 were the same: He meant the two lines; the E350 line, and the E450 line have not changed significantly over the years.

Correct.


For what it’s worth, initial 2023 specs (picture below) show not much changing for next year either.
.

[EA37TS]

Back a few years ago I was able to download the Ford specs on frame metal thickness, spring thickness, number of leafs in the springs etc… on the stripped and cutaway chassis’s. Can’t find that info anymore and there was a difference between the 350 and 450. One of the easiest differences to spot was the extra leaf in the springs on the 450.

Not sure if things changed over the past 7 or 8 years.

If someone knows what they’re doing the info can be found on Ford Parts.

[Chance]

Originally Posted by EA37TS

Back a few years ago I was able to download the Ford specs on frame metal thickness, spring thickness, number of leafs in the springs etc… on the stripped and cutaway chassis’s. Can’t find that info anymore and there was a difference between the 350 and 450. One of the easiest differences to spot was the extra leaf in the springs on the 450.

Not sure if things changed over the past 7 or 8 years.

If someone knows what they’re doing the info can be found on Ford Parts.

You can still find much of that data.

Ford specs show the frame rails on Cutaway E-450 are a little thicker (0.248) than on E-350 (0.228), but specs for stripped chassis show the slightly thinner frame rail on both.

Front suspension are all the same 5,000-pound Twin I-Beam. Ford just installs different coil springs based on load.

Rear suspension use three axles — 7,800, 8,500, and 9,600 pounds. Springs are sized based on load. The 7,800 and 8,500 pound axles are used on E-350 and the 9,600 pound axle on E-450.

Wheels, tires, and brakes on all DRW show same specs; there is some slight difference on SRW E-350.

In case of SRW E-350, where there is greatest theoretical “derating”, the LT245/75R16 tires limit rear axle to 6,084 pounds.

I personally still have a hard time grasping why Ford will build a SRW F-350 pickup with 11,500-pound GAWR and allow it to tow a 40-foot 5th Wheel and not upgrade SRW E-350 to at least 11,000 pounds by installing higher capacity tires/wheels and front springs. Need must just not be there, because from a rear blowout safety standpoint, I’d rather have one on a 23-foot 11,000-pound motorhome than on a pickup towing a 15,000+ pound 5er.

[Hooligan2]

Slow down-- It makes sense, the combined limits for front and rear axle ALWAYS will equal or exceed the GVWR. Otherwise that would be the limiting factor. And it may be hard for Ford to find a front axle rated at 4823.5 lbs to make it exactly fit the GVWR..
Mercedes also states the extra axle capacity can be used to balance loading but not to exceed GVWR.