How do you figure in WDH with total weight
03-30-2015, 10:57 PM
#1
How do you figure in WDH with total weight
Im looking at a 2013 F150 4x4 lariat with max tow and short bed. I currently have a 32ft travel trailer that dry weight is 7000 lbs and max weight of 9200 lbs. I don't plain on having this trailer much longer and I will be looking at lighter trailers. The truck has a GVWR of 7650 lbs and the yellow tire sticker says cargo and occupants should not exceed 1555 lbs. So with all this I would think my trailer absolutely loaded at most would way 8500 lbs as I never carry water. My next step is to take the trailer to a scale. My main question is how do I figure in the WDH into all of this? I have hooked my trailer to this truck with the WDH and it looks great no sag and it drives nice in town and on the interstate while test driving.
03-31-2015, 10:25 AM
#2
Senior Member
The way I tested (maybe not the right way but it worked) is weigh your whole set up as is for towing. Always weigh the 3 axles separately, truck front, truck rear and trailer. Then I did it again with the spring bars disconnected and finally weighed the truck and trailer separately. Once you have all your weights you can adjust your set up to "move" the weight around or if you're happy leave it as is. I know another way is with a tape measure but I prefer the scale as I think you can see what's happening better.
03-31-2015, 11:16 AM
#3
Grumpy Old Man
What EventHorizon said. Know all your exact weights, including tongue weight. Your goal is to distribute the tongue weight so you have
20% to 25% to the trailer axles
20% to 25% to the front axle of the tow vehicle
50% tp 60% remaining on the rear axle of the tow vehicle.
So when you weigh the rig both times, with and without the spring bars attached and adjusted, then you can see the difference in the weight on each axle of the rig.
Example:
Ypur wet and loaded rig has 1,100 pounds tongue weight. So the trailer axles should weigh 220 to 275 pounds more with the spring bars installed. The front axle of the truck should also weigh 220 to 275 pounds more with the spring bars installed. The rear axle of the truck should weigh 440 to 550 pounds less with the spring bars installed. The total of front and rear axles should be 220 to 275 pounds less with the spring bars attached.
You don't need to know the weight of the trailer to make these calculations. But you do need to know the tongue weight. If you don't have a tongue weight scale, then you can get the tongue weight by weighing the rig on a CAT scale, then weighing the tow vehicle without the trailer. Add the front and rear axle weights to get GVW of the pickup. The difference in GVW is your tongue weight.
If you don't have it adjusted to give you results within those percentagers, then continue adjusting. Tightening the spring bars will reduce the weight on the rear axle. Changing the angle of the hitch head to the ground will change the percentage of weight distributed to the trail;er and front axles.
Another example, this time a real-life example. My tongue weight was 650 pounds. 230 pounds (35%) was distributed to the front axle. 140 pounds (22%) was distributed to the trailer axles. 360 pounds (54%) remained on the rear axle. Not bad, but a bit too much going to the front axle. Needs fine tuning of the angle of the hitch head to reduce the percentage of tongue weight going to the front axle. I'll get a round tuit some day.
In the meantime, it tows great.
20% to 25% to the trailer axles
20% to 25% to the front axle of the tow vehicle
50% tp 60% remaining on the rear axle of the tow vehicle.
So when you weigh the rig both times, with and without the spring bars attached and adjusted, then you can see the difference in the weight on each axle of the rig.
Example:
Ypur wet and loaded rig has 1,100 pounds tongue weight. So the trailer axles should weigh 220 to 275 pounds more with the spring bars installed. The front axle of the truck should also weigh 220 to 275 pounds more with the spring bars installed. The rear axle of the truck should weigh 440 to 550 pounds less with the spring bars installed. The total of front and rear axles should be 220 to 275 pounds less with the spring bars attached.
You don't need to know the weight of the trailer to make these calculations. But you do need to know the tongue weight. If you don't have a tongue weight scale, then you can get the tongue weight by weighing the rig on a CAT scale, then weighing the tow vehicle without the trailer. Add the front and rear axle weights to get GVW of the pickup. The difference in GVW is your tongue weight.
If you don't have it adjusted to give you results within those percentagers, then continue adjusting. Tightening the spring bars will reduce the weight on the rear axle. Changing the angle of the hitch head to the ground will change the percentage of weight distributed to the trail;er and front axles.
Another example, this time a real-life example. My tongue weight was 650 pounds. 230 pounds (35%) was distributed to the front axle. 140 pounds (22%) was distributed to the trailer axles. 360 pounds (54%) remained on the rear axle. Not bad, but a bit too much going to the front axle. Needs fine tuning of the angle of the hitch head to reduce the percentage of tongue weight going to the front axle. I'll get a round tuit some day.
In the meantime, it tows great.
Last edited by smokeywren; 03-31-2015 at 11:36 AM.
03-31-2015, 12:08 PM
#4
Senior Member
I made a spreadsheet tool and posted it up here once before that can help you. Specifically the 3rd tab in the tool called "Load Estimator" allows you to plug in tow-vehicle and trailer information to help determine the towing capacity required from the TV:
https://www.f150forum.com/f82/traile...tility-244126/
https://www.f150forum.com/f82/traile...tility-244126/