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What would be the difference between a CAT scale and just using the scale that the Department of Transportation uses to weigh the trucks by the roads?
No significant difference as long as the DOT scale will tell you the weights on the front, rear, and trailer axles.
Add the weights on the front and rear axles and compare to the GVWR of the tow vehicle.
Add the GAWRs of the trailer axles and compare to the weight on the trailer axles. For example, my small TT has two 2,800-pound axles, so my total trailer axle weight could be up to 5,600 pounds without the trailer being overloaded.
Compare the weight on the front axle to the fGAWR of the tow vehicle.
Compare the weight on the rear axle to the rGAWR of the tow vehicle.
Total the weight on all axles and compare to the GCWR of the tow vehicle.
Door sticker:
Payload - 1699
GVWR - 7050
Front GAWR - 3600
Rear GAWR - 3850
Looks like I'm doing fine. Next trip I'll go for tongue weight on the trailer.
Should I go for more front weight on the truck, or leave the WD setup alone?
Should I go for more front weight on the truck, or leave the WD setup alone?
Not enough info to tell. You need two more passes over the scale.
-- With the truck loaded the same as the earlier weighing, and with the trailer but without the spring bars tight.
-- Truck only, no trailer.
Then you can do the match to check your setup.
1] Without the spring bars tight, add the weight on the two truck axles to get GVW.
2] Without the trailer, add the weight on the two truck axles to get GVW.
3] Subtract the GVW without the trailer from the GVW without the spring bars tight. The answer is hitch weight.
4] Notice the difference in the the weight on the trailer axles, with and without the spring bars tight. The goal is to transfer about 20 to 25% of hitch weight to the trailer axles when you tighten the spring bars.
Example: Hitch weight = 640
Without spring bars:
Front:3040
Rear: 3880
Trailer 3480
GCW 10400
With spring bars tight:
Front: 3280 = +240 = 37.5% of hitch weight distributed to front axle = too high, goal is 20 to 25%
Rear: 3520 = - 360 removed = 290 remaining hitch weight on the rear axle = 44.6%. Goal is 50% to 60% remaining on the rear axle, so the spring bars are a bit too tight, removing a bit too much weight from the rear axle.
Trailer: 3620 = + 140 = 21.9% of hitch weight distributed to the trailer axles = just about perfect
GCW 10,420 = 20# scale rounding error.
Analysis, we have to reduce the tension on the spring bars so the hitch weight remaining on the rear axle is 50% to 60% of hitch weight. That will reduce the weight on the front axle which is needed, but it will also reduce the weight on the trailer axles which we don't need.
So with 650 pounds hitch weight, we need 325 to 390 pounds on the rear axle, and 130 to 160 pounds distributed to both the front and trailers axles. So first we adjust the spring bars to get the weight on the rear axle right, then leave the spring bars alone while we change the angle of the coupler to the ball to balance the weight distributed to the front and trailer axles.
My trailer weight (5000 to 6000 pounds) is well within the capacity of my 2014 F150 supercab. I have a really cool little hitch scale from Etrailer.com that tells me that the unhitched, level, tanks full hitch weight of my trailer is 650 pounds. I weighed the trailer yesterday with the load distributing bars on and with the truck and trailer level, and got a weight of 5120 pounds. Does this mean my trailer weighs 5120 + 650 = 5770 or should I have weighed the trailer with the load distributing bars off? Thanks for any replies. Jim
I weighed the trailer yesterday with the load distributing bars on and with the truck and trailer level, and got a weight of 5120 pounds. Does this mean my trailer weighs 5120 + 650 = 5770 or should I have weighed the trailer with the load distributing bars off?
Depends on what you are trying to determine.
Gross trailer weight = trailer axle weight without the spring bars tightened, plus tongue weight.
The truck's GVW is the weight on the two truck axles with the spring bars tightened.
A properly adjusted WD hitch should distribute some of the hitch weight back to the trailer axles. So your numbers will result in a gross trailer weight overstated by around 130 to 160 pounds, depending on how good a job you did in setting up and adjusting the WD hitch.
However, gross trailer weight is not a spec you need to be concerned about. Use it only to help match trailer to tow vehicle.
When on the road and weighing the rig on a CAT scale, the scale will tell you the weight on the front, drive and trailer axles. Add the weights on the front and drive axles and compare to the GVWR of the truck. Compare the weight on the drive axle to the rGAWR of the truck. Compare the weight on the trailer axles to the combined GAWR of the trailer axles. Then finally, compare the combined total of the weight on all the axles to the GCWR of the tow vehicle.
Notice that none of those comparisons is to the GVWR of the trailer. The CAT scale will not tell you the GVW of the trailer, and you need not worry about it.
I got all the information I needed with three trips across the scale, $11 first weigh, $2 for each re-weigh, $15 total. I used a broom handle to push the button on the squawk box so I could stay in the truck.
Last edited by atwowheelguy; 03-30-2017 at 12:36 AM.
I am confident that my trailer, 3 people and all of my gear are not too heavy for my truck. The combined rig drives fine with the weight distribution bars and hitch receiver set for a level truck and level trailer. I am curious what my trailer weighs and want to know if it is correctly balanced for 12-13% on the ball. I know that the unhitched weight on the ball is 650 pounds with full tanks, extra batteries and gear. I am mostly just curious what my trailer weighs. I also want to know if I should shift some of the heavy items in the trailer forward for more hitch weight.
Hello to another Texan. I lived in Corpus Christi, Houston and San Antonio until I was 25. Jim
03-19-2017, 05:21 PM
Trailer weight w springs on or off
