2020 Phaeton 40IH OCCC question

[NLOVNIT]

OK, finally got our empty numbers:

CAT weighed weight: 34,320 (Steer 12,880 / Drive 21,440)
According to the 2018 Brochure, GW = 39,600
So that leaves me 5,280 CC.

At some point, I'd like to get it weighed as it is loaded up for a season of travel. Someday.

Lori-

[DeWat]

Originally Posted by NLOVNIT

OK, finally got our empty numbers:

CAT weighed weight: 34,320 (Steer 12,880 / Drive 21,440)
According to the 2018 Brochure, GW = 39,600
So that leaves me 5,280 CC.

At some point, I'd like to get it weighed as it is loaded up for a season of travel. Someday.

Lori-

Unfortunately, you've only done the first half of the equation, which was the reason for my post# 11. This is the same formula that the manufacturers use, which is why their occupant cargo carrying capacities (OCCC) are inflated. They take the total axle weight rating (GAWR) for all axles combined and subtract the weight of the empty motorhome (full fuel, engine fluids, and DEF) to come up with the OCCC. The problem is once any axle is over its GAWR, you are overweight.


According to the brochure for the 2018 Phaeton 40IH, the GAWR for the front axle is 15,600 and the GAWR for the rear axle is 24,000, giving it a GAWR of 39,600 (exactly what you reported). The problem based on your current weight report is that you only have 2,720 OCCC on the front axle (15,600 - 12,880), and only have 2,560 OCCC on your rear axle. The good news is that that's still a lot of OCCC, but it's not 5,280. Knowing that, also know that everything you put in/on the motorhome, between the axles is going to add to both axles (this includes people). Naturally, the weight distribution will change with proximity to the axle, so a very heavy object stored in your front basement bay will put much more of its weight on the front axle than the rear axle, but the weight will be distributed between the axles. Also keep that in mind with your fresh water tank, which is probably just in front of the rear axle. With a 100 gallon fresh water tank and water weighing ~ 8.35 pounds per gallon, a full water tank is going to take close to an additional 835 pounds from that 2,560 rear GAWR (again, because of distribution a minimal amount of that 835 pounds will come from the front GAWR).


Finally, the biggest two reasons for a 4-corner weight when you can have one done is that the weight on each corner can be just as important. First, you want to balance the side-to-side weight on each axle as much as possible. You will not be able to help some things, but having the sides within 500 - 1,000 pounds of ech other would be ideal. Second, you will have real numbers to work with concerning your air pressures. With axles weights, you're using an air pressure of the axle weight divided by 2... hopefully, with a little plus fudge factor. However, with a 4-corner weight, you know exactly which side is the heaviest, which is what you are going to use to determine your air pressure for that axle. This is extreme for example purposes, but if you're basing your air pressure on an axle weight, and one side is 2,000 pounds heavier than the other side, you could be running an underinflated tire on that side.

[NLOVNIT]

Originally Posted by DeWat

....
According to the brochure for the 2018 Phaeton 40IH, the GAWR for the front axle is 15,600 and the GAWR for the rear axle is 24,000, giving it a GAWR of 39,600 (exactly what you reported). The problem based on your current weight report is that you only have 2,720 OCCC on the front axle (15,600 - 12,880), and only have 2,560 OCCC on your rear axle. The good news is that that's still a lot of OCCC, but it's not 5,280. .

Maybe I'm missing it. Please tell me why isn't it 5,280. Even by your math above it is. I know it may not be ALL that, but it's gotta be darned close based on the conditions I already posted. The numbers were as I stated & I did post I have not had it weighed loaded for seasonal travel yet. That will change when I do & I will adjust loads accordingly based on a proper 4-corner weight.

Lori-

[DeWat]

Sorry Lori, I'm not trying to present an argument, just explaining why it is not as simple as combining the available weights for both axles. As I mentioned, the minute any axle goes over its own GAWR, the motorhome is officially overweight. Since you have 2,720 pounds available to you on the front axle and 2,560 pounds available to you on the rear axle, my bet is that you will have probably overloaded one of the axles once you have 3,000 pounds of cargo (if not before). Sure, I can be wrong, but this is typically how it works. This is why there were complaints here on iRV2 several years ago about Newmars coming from the factory close to overweight, or even overweight already. While they were showing plenty of OCCC, their front axles were already close to maxed out.

Tiffin did what they could to help front axle GAWR a couple years ago by going from 295 tires up front to 315s on the tag axle coaches. The problem was, our previous '15 Allegro Bus 45LP included, is that when they first moved up to the larger front tire, they still put them on the same 8.25 inch rims. After a couple years of that, even Michelin put out a bulletin stating that 315s should not be placed on the slimmer 8.25 rims that Tiffin was using when they first went to 315s.


This is why I said in post# 11 tag axle coaches struggle at the front axle and single rear axle coaches struggle at the rear axle. Even our current '19 Entegra Anthem is weight challenged. Our Anthem has an OCCC listed as 7,793 pounds, but when we did our 4-corner weight at Spartan last year, our front axle with full water and modest (really, relatively light) basement cargo, minus the DW & I came in at 16,270 pounds. With a 17,000 front axle GAWR, the minute we put more than 730 on that front axle, less than that once we get on, the coach is overweight. Entegra has since gone to a 20,000 front axle GAWR in 2020 or 2021 Anthem, but that still would not give us the full listed 7,793 OCCC without overloading the coach.

I apologize again if it sounded like I was being critical. My only goal was to show you why manufacturer OCCC cannot be trusted.


EDIT: If you compare the factory weight sticker with the total weight when we weighed at Spartan, you can see that we only had an additional 1,333 pounds on the motorhome (and the bulk of that was the full fresh water tank which is how we wanted to weigh). Using the 7,793 OCCC, we should still have another 6,460 pounds to go before we're overweight, BUT, again we only have 730 pounds left to go on the front axle before the coach is overweight.

[NLOVNIT]

I get the overloaded axle thing. That's all good to know.

Unless I misinterpreted, the OP wanted a comparison on an empty, all electric 40IH coach. I offered my numbers because I have an all electric 40IH. Ours (at pick up) was as close to factory shipped as his. So we're comparing apples to apples (i.e. empty 40IH's). The only thing I don't know is if his shipped from the factory weight had a full fuel tank, the box of extra floor tiles & 2 adult occupants as ours did when we weighed ours at the CAT.

Lori-

[zombiewoof]

Lori,
Thank you for your posts. Yes, I wanted to know the OCCC of other IH coaches for comparison to mine since the 4920 lbs was less than I expected. In general, all electric IH coaches will have a higher OCCC than a propane IH coach. I did not understand that at the outset of this thread, now I do. Also, just for clarity sake, the UVW is derived for a motorhome with all fluids in the vehicle, including a full tank of fuel.

[DeWat]

Originally Posted by NLOVNIT

I get the overloaded axle thing. That's all good to know.


...

Lori-

Very well, there's no need to belobor this then; however, know this... the manufacture's OCCC don't mean a thing. If there's ever an event (accident, breakdown, etc) that can be tied back to axle overloading, your motorhome will be considered overweight and it will get expensive. The manufacture will be able to back out saying that they said that's how much weight was available to you, true, BUT, they are not responsible for how you loaded it.

[wingnut60]

and it will get expensive.

Can you cite an example? Lots of anecdotal stuff, where is the real-life lawsuit?

[DeWat]

Originally Posted by wingnut60

and it will get expensive.

Can you cite an example? Lots of anecdotal stuff, where is the real-life lawsuit?

Nice try... Ignorantia juris non excusat


While it is true that just "Just because I saw it on the intenet" is not true, the opposite is equally true, "Just because something is not on internet does not make it false. (I am not one of those who will say that your insurance can just arbitrarily cancel their contractual obligation). This country goes through hundreds if not hundred of thousands of civil lawsuits daily. How many of them are posted without digging into municipal law books. Negligence only has four criteria; duty, breach, causation, and damages. I say again, "Ignorantia juris non excusat", and with that, I'm out.

[wingnut60]

"Ignorantia juris non excusat"

Is that carved on the LA courthouse where Perry Mason won all his cases?

[CLIFFTALL]

This thread has drifted off topic and the OP has asked it to be closed. Thanks to all that contributed to the topic.
Cliff