Using a CAT scale to determine tongue weight?

**Danmiller35** · 03-28-2018, 12:41 PM

We purchased an Imagine 2400BH back in Dec and one our first trip out I took it to the CAT scale to verify all my loaded weights and dial in my WDH. Frankly I don’t want to buy a scale to determine my exact tongue weight if I don’t have to. I know there are alternative methods using home scales, etc but since I was there at the scale, I thought I’d see if this would work? Can anyone tell me if the following is a valid alternative to determining tongue weight? We’re newbies to all this but between this forum and the GD FB page I feel much better prepared.

Weigh #1 (truck + TT): 12,680
Weigh #2 (hitched TT, TT axles on scale): 6,060
Weigh #3 (truck only): 5,980

TT GW: (#1) - (#3) = 6,700
Tongue WT: 6,700 - (#2) = 640

Other than the fact that 640 lbs is just shy of the 10%-15%, can anyone sharp-shoot this method? My thought is that this isn’t the exact weight since the WDH is shifting some weight to the front axle? Maybe I’m answering my own question! I’m also trying to figure out the tongue weight to determine where I’m at on payload- based on my estimates I only have about 2-300 to spare. Am I way off base on this?

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**jim1521** · 03-28-2018, 01:32 PM

Hi Dan,
I have a spreadsheet that I can email you that will do all the math for you from a CAT scale, but there are additional parameters needed:

Here are the fields that I use. The numbers in the parentheses are my max numbers for my vehicles; they will be different for yours)

18,020 Gross Weight (Max 19450 from scales receipt) - This comes right off the receipt
7,800 Truck baseline weight (7580 just me/7800 loaded) - This is what I baselined my truck weight. Only have to do it once.
4,340 Steer Axle Weight (Max 4900 from scales receipt) - This comes right off the receipt
4,660 Drive Axle Weight (Max 4900 from scales receipt) - This comes right off the receipt
9,020 Trailer axle weight (Max 10,200 from scales receipt) - This comes right off the receipt
1,200 Tongue Weight (Max 1260. Calculated. Do not change) - This is a calculation based on input of the above numbers
9,000 Truck actual weight (Max 8800. Calculated. Do not change) - This is a calculation that includes the computed tongue weight
10,220 Trailer actual weight (Max 10,995. Calculated. Do not change) - This is a calculation of the true trailer weight
12% % Tongue Weight (Calculated. Do not change)

Here's what my report looks like:

Click image for larger version.

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Size: 80.4 KB
ID: 12052

In the meantime, look at your CAT scale receipt. What is the Steer Axle Weight and Drive Axle weight? Also, what is the GVWR for your truck? The weight that you posted for truck only: was that in a "full" configuration (wife, kids, dogs, Snickers bars, etc.)?

Jim

**Gumpster** · 03-29-2018, 05:04 AM

Jim can you put you spreadsheet in the Reference Library if its not to much trouble so other people can get to it.

**burgpath** · 03-29-2018, 05:17 AM

When I did the weight on my TT I pulled up on the scales with the tongue and trailer wheels on different pads. Unhooked the trailer and truck, which I pulled off. Hot the button, got weighed. Backed up and hooked up, then got off the scale. With 2 people, it not a long process at all.

**Danmiller35** · 03-29-2018, 07:47 AM

Originally Posted by jim1521

Hi Dan,
I have a spreadsheet that I can email you that will do all the math for you from a CAT scale, but there are additional parameters needed:

Here are the fields that I use. The numbers in the parentheses are my max numbers for my vehicles; they will be different for yours)

18,020Gross Weight (Max 19450 from scales receipt) - This comes right off the receipt
7,800Truck baseline weight (7580 just me/7800 loaded) - This is what I baselined my truck weight. Only have to do it once.
4,340Steer Axle Weight (Max 4900 from scales receipt) - This comes right off the receipt
4,660Drive Axle Weight (Max 4900 from scales receipt) - This comes right off the receipt
9,020Trailer axle weight (Max 10,200 from scales receipt) - This comes right off the receipt
1,200Tongue Weight (Max 1260. Calculated. Do not change) - This is a calculation based on input of the above numbers
9,000Truck actual weight (Max 8800. Calculated. Do not change) - This is a calculation that includes the computed tongue weight
10,220Trailer actual weight (Max 10,995. Calculated. Do not change) - This is a calculation of the true trailer weight
12% % Tongue Weight (Calculated. Do not change)

Here's what my report looks like:

In the meantime, look at your CAT scale receipt. What is the Steer Axle Weight and Drive Axle weight? Also, what is the GVWR for your truck? The weight that you posted for truck only: was that in a "full" configuration (wife, kids, dogs, Snickers bars, etc.)?

Jim

TV & TT - steer axle (3300), drive axle (3380), trailer axle (6000), GW (12680)

TV only - all axles except drive axle (6060) were 0.

TV only - steer (3200), drive (2780)

TV GWR - 7000, TV and TT were loaded for our camping trip w/me, kid, dog minus wife/one kid (+200 lbs), TV GCWR is 15860.

TV GAWR 3900(fr), 4150 (rear), but this is w/P25570R18s. I have P255R20s that put my payload at 1435. I plan on upgrading my tires to rid myself of the p-rated tires.

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**Nuffsaid** · 03-31-2018, 10:51 AM

This is how I establish weights. Weigh your truck front axle and rear axle with normal amount of passengers in the truck. If you travel with two adults in the truck, scale with two adults. Record your weights. Make sure you have a full tank of fuel and normal items carried in the truck, tools etc. Next hook up to the trailer and weigh front and rear axles of truck again and then weight trailer axles. The difference in your empty truck weight and the loaded truck weight on the axles will tell you where the added weight of the trailer went. This is a more accurate way of measuring weight than just unhooking the trailer to determine tongue weight. Since the hitch is rearward of the axle, tongue weight can remove weight from the front axle of the tow vehicle unless the equalizing hitch transfers some weight forward like designed.

**nighthawkmiata** · 03-31-2018, 11:30 AM

I agree with what Nuffsaid stated. The most straightforward and accurate way of determining tongue weight is to start by weighing the truck alone fully loaded with passengers, fuel, cargo, etc. You should add the steering and drive axle weights together to come up with this. Call this number A. Then hitch up the trailer and get the weight of the truck again. Call this number B. The difference (B - A) is your tongeu weight.

Keep in mind thought that you need to determine the front and rear axle weights on your truck with the trailer attached so you are sure that you don't exceed the GAWRs of either truck axle.

**Bob/OlallaWA** · 03-31-2018, 12:04 PM

So many ways to weigh and get approximate weights. I guess the way you do it would depend on where your close to being over the weight rating. If going after the tongue weight, you really need to weigh the trailer axles before and after setting the hitch as some weight is also added to the trailer axles when hooked up and bars activated. On my trailer the hitch adds about 500 lbs to the trailer axles when I set the hitch to return the front axle of truck to unloaded weight. I find my best and closest tongue weight reading is to set the tongue of the trailer on the scale with trailer level and not on the truck. On my set up the weight on the trailer tires is my concern. I weigh each trailer axle alone and also one side of each axle and subtract to get all four wheel weights. Not enough room between scale and house to get the left side tires on the scale I would go to the 16 inch Lt tires but not enough room in the wheel wells for that. I use a DOT scale when they are not weighing trucks.

**jim1521** · 03-31-2018, 12:46 PM

Originally Posted by Gumpster

Jim can you put you spreadsheet in the Reference Library if its not to much trouble so other people can get to it.

Yes, I'd be happy to.

How do I do that?

EDIT: Ok, I "believe" I posted it up to the Reference Library. It's not showing up there yet.

Thread is titled "Tow Vehicle/Trailer Weight Calculations Spreadsheet" and includes a .zip attachment that has the Excel spreadsheet with comments and annotations.

**tomilee** · 05-03-2019, 12:16 PM

First of all, congrats on your Imagine 2400BH, I am actually thinking of buying the same model.
My family loves the bunk beds and the layout.

I just wanted to drop a line because I was also calculating all the weight numbers for the trailer.

Please consider that Imagine 2400BH's tongue weight can go as high as around 1125lbs at max considering TT's GVW 7500lbs. (7500lbs * 15%)
Even if you don't apply all the max ratings, it should be around 871lbs (your TT weight 6700lbs * 13%)

Your tongue weight looked like 640lbs because WD transferred the weight to TV's front axle and TT's axle, but it is not the actual tongue weight.
To more accurately measure the tongue weight, you will have to measure the both TV and TT with WD disengaged.

2400BH's dry weight with 1 gas tank is usually around 560lbs and adding 2x batteries (130lbs), another full gas tank (60lbs), WD hitch (100lbs) and other your camping gears (100lbs)
You will likely see 950lbs tongue weight at minimum without WD activated, it will be brought down to around 700lbs after applying WD.
That said, you are seeing about 14% tongue weight of your TT's 6700lbs loaded weight.

I hope this helps.