Scale Weight is Puzzling. Can Anyone Help Explain?

[rjr1959]

I have a 2024 3941FO. I just weighed at a CAT scale. The trailer weight on the ticket is 14500 lbs. The UNLOADED RIG from the factory sticker is supposed to weigh around 15,650 (I don't have the exact number at the moment). I don't understand how this can possibly be! How can a fully loaded rig weigh less than the sticker weight from the factory? I know the tongue weight ends up on the truck (2020 Ford F450), is that supposed to be subtracted from the trailer axle weight? That's the only thing I can figure but I don't quite grok the physics of that...

I weighed again (on the same trip) at a different CAT location, and the numbers are identical.

The exact numbers are: Steer Axle 5380, Drive Axle 7860, Trailer Axle 14500, Gross Weight 27740.

Thanks!
Robert

2024 Montana 3941FO
Full Timer Since 2022

 

[Theunz]

You would have to weigh the truck by itself and then subtract that rear axle weight from your first rear axle weight to find out how much tongue weight you have. Add the tongue weight to your trailer weight for the total weight. You probably have around 3,000 lbs. of tongue weight which would make your total trailer weight about 17,500

 

[rjr1959]

OK, I get it now. I did weigh the truck just after I bought it (fully loaded as it is now) and the drive axle was 4660. So 7860 (weight with rig hooked up) - 4660 = 3200 lbs tongue weight. Adding 14500 + 3200 = 17,700 lbs. Which means I'm overweight on the trailer by about 900 lbs. The GVWR on the trailer is 16810. Which is about 1500 lbs of cargo capacity. Which is incredibly, stupidly low for a 43 foot 5th wheel IMO. I notice the next model year they upped it by 1000 lbs.

Not much I can do about it - except buy a trailer and constantly offload 900 lbs into it every time I change locations. Not fond of that idea. Not sure what I'm gonna do. I really like the rig, but I don't like driving around overweight like this. I guess either the trailer, a different rig, or just take my chances are my three options.

Thanks for the help!

Robert

 

[Theunz]

Sure makes you wonder if the product developers at Montana have even the slightest clue about how their products are used. For instance your 43 footer can only hold about 1,500lbs.of cargo while my 35 footer’s cargo capacity it around 4,000lbs. I don’t know where I could even find the room for that much weight!

 

[LeftOverParts]

Something seems off. If your tongue is 3200 lbs and if it is usually 20% of your trailer weight, 3200lbs/0.20=16,000 lbs. (Your pin ratio fully loaded would have to be about 18% to arrive at 17,700 lbs). Maybe I’m missing it but your truck steer and rear axles weights without the trailer aren’t shown.

Since there’s a concern that you are overweight, might be helpful to double check. You might get a different answer if you follow this:

From: How to Weigh a Travel Trailer or Fifth Wheel

Here’s your 2024 specs and carry cap shows 1,543 lbs. (2026 is about 700 lbs more). Interesting the empty pin weigh ratio calculates to 18.7%.

 

[twindman]

The current specs on Keystone have the carry capacity a full 1000 lb more than you state. Total GVWR is around 18000. Maybe there was a misprint where ever you got your info.

 

[MandK]

I think the FO was one of the trailers that Montana went to 8k axles for 2025, increasing CCC and gvwr. I know they did on the RK because we were looking hard at that model.
Edit: Yes I see now in post #3 above he mentioned that.

 

[rjr1959]

Sure makes you wonder if the product developers at Montana have even the slightest clue about how their products are used. For instance your 43 footer can only hold about 1,500lbs.of cargo while my 35 footer’s cargo capacity it around 4,000lbs. I don’t know where I could even find the room for that much weight!

I know. It's absolutely ridiculous that a rig this large can only carry 1500 lbs. It's obviously a rig that could commonly be used by a full timer. I see the next model year (2025) they almost doubled the capacity. But it's no one's fault but my own for greatly underestimating how much stuff I had.

 

[rjr1959]

Something seems off. If your tongue is 3200 lbs and if it is usually 20% of your trailer weight, 3200lbs/0.20=16,000 lbs. (Your pin ratio fully loaded would have to be about 18% to arrive at 17,700 lbs). Maybe I’m missing it but your truck steer and rear axles weights without the trailer aren’t shown.

Since there’s a concern that you are overweight, might be helpful to double check. You might get a different answer if you follow this:

View attachment 1949184

From: How to Weigh a Travel Trailer or Fifth Wheel

Here’s your 2024 specs and carry cap shows 1,543 lbs. (2026 is about 700 lbs more). Interesting the empty pin weigh ratio calculates to 18.7%.

View attachment 1949187

Thanks for that info! I think I listed the truck steer and drive axle weights (no trailer). The front axle was

The current specs on Keystone have the carry capacity a full 1000 lb more than you state. Total GVWR is around 18000. Maybe there was a misprint where ever you got your info.

No, that's from the sticker on the rig. They upped it in 2025 by a lot as another reply mentioned.

 

[Todd727]

You only subtracted the drive axle. Some of the weight of a 5th wheel is transferred to the steer axle, it's one of the reason you get a 5th wheel or gooseneck trailer. On your empty weight ticket, subtract that full truck weight from the full weight of the truck and trailer. That will be the weight of the trailer. For the tongue weight, subtract the trailer axle weight from the trailer weight calculation you just did and you will have the tongue weight.

If you have both weight tickets, post pictures of them here.

 

[Todd727]

Here are my weights using my F450 and Montana:

So, you can see my truck is 9500 lbs empty. That means the trailer added 16,220 lbs. in the second weigh and the tongue weight placed onto the truck is 4200 lbs, which is nearly 26%. The gross weight of the truck is 13,700 which is just below the GVWR of 14,000. And I know from the VIN sticker that both axles are within spec.

At this point the silly yellow load sticker is meaningless, because I'm using actual weights. The yellow sticker on the truck is only useful when shopping, as it assumes an empty, stock, as built truck.

 

[rjr1959]

You only subtracted the drive axle. Some of the weight of a 5th wheel is transferred to the steer axle, it's one of the reason you get a 5th wheel or gooseneck trailer. On your empty weight ticket, subtract that full truck weight from the full weight of the truck and trailer. That will be the weight of the trailer. For the tongue weight, subtract the trailer axle weight from the trailer weight calculation you just did and you will have the tongue weight.

If you have both weight tickets, post pictures of them here.

You are absolutely right - I didn't even think of that. Much appreciated.

The total weight of the truck (loaded, full fuel, dog/cat and me sitting in it) is 9860 lbs. The total weight of the truck and trailer is 27740.

Trailer Weight: 27740 - 9860 = 17880 lbs
Tongue Weight: 17780 - 14500 = 3280 lbs

Yep, trailer is definitely overweight by roughly 1000 lbs. As I mentioned before, my choices:

1. Buy a different rig
2. Buy a trailer, hook it to the rig, and transfer 1000 lbs from the rig into the trailer.
3. Throw out 1/2 of my belongings. Interesting thing is, it all fits comfortably in the storage/cabinets I have. This rig is just stupidly under powered when it comes to cargo capacity.
4. Take my chances.

I'm in Vegas now, so there are plenty of dealers. Perhaps I'll take a look around.

***Help from EVERYONE is much appreciated!***

 

[rjr1959]

I wonder, would it be possible to simply put 8k axles on this rig, and upgrade the tires from "G" to "H" ?? From what I've read, it's a solid "No". But I doubt they did anything other than this in the 2025/2026 models which can carry almost 1500 lbs more than my 2024.

 

[jetskier]

I'd go with option 4. You're not that much over the axle rating. You could do the 8k axle upgrade, but you'd be better served just getting disc brakes with the 8k hubs and 8k bearings on the 7k axle. I'd be willing to bet you still have negative (upward) camber in the axle beam at the center when fully loaded. They have been equipped with 4000# springs for the past 4 or 5 years so you're good there. The frame and tires will be fine and you have more than enough truck.

 

[Lcbuddy]

Maybe this will help…this is the easiest way to do it.

 

[Lcbuddy]

We have 3123RL (35’) and a Ram 3500 diesel, here are my weights
Truck weight
12300 truck w/ trailer,
11400 trailer weight
Total 23700 Combined
8850 truck without trailer
Making my trailer weight 14,850

 

[rjr1959]

I'd go with option 4. You're not that much over the axle rating. You could do the 8k axle upgrade, but you'd be better served just getting disc brakes with the 8k hubs and 8k bearings on the 7k axle. I'd be willing to bet you still have negative (upward) camber in the axle beam at the center when fully loaded. They have been equipped with 4000# springs for the past 4 or 5 years so you're good there. The frame and tires will be fine and you have more than enough truck.

Thank you for that information. I put a 4 ft level on it, it looks higher in the middle of the axle if that's what negative camber means.

Is it a big job to switch out the hubs and bearings? I do almost all my own mechanical work, but of course being full-time I don't really have access to a lift or multiple floor jacks. Would one order these parts from Lippert?

Also the tires on it have a G weight rating. Everything RV manufacturers do is right on the borderline it seems. I wonder if it'd be worth putting H rated tires on it.

 

[Carl n Susan]

I noticed the new Montanas at my dealer have 8K axles and the tires have been upgraded to H rated Sailuns.