Making Sense of WD hitches
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Joined: May 2010
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Making Sense of WD hitches
After quite some thought and reading very confusing articles on how a WD hitch works and how much weight it transfers to the front axle and the trailer axles, I finally thought of an easy way to see what is happening.
Consider my trailer. It weighs 7400 lbs and has 960 lbs on the tongue before hooking up. My trailer coupler is 21' from the center of the trailer axles. Since the tongue has 13% of the total weight, the system can be thought of as a simple arm from the center of the axles to the ball with the entire weight 13% of the way forward. In other words, it is like having a 21' arm with 7400 lbs 2.73 feet from the pivot point (center of my axles).
When hooked up without a WD hitch, it lifts up on the front axle of my truck because the 960# tongue weight is put behind my truck's rear axle, just like a see-saw. Now consider the case when the WD hitch is adjusted so the front axle does not change height when hooking up. The WD hitch effectively places all of the tongue weight directly over the rear axle. In some cases, the front axle drops a little, but let's just consider the case when it doesn't move at all.
Now with this scenario, the system (trailer) acts like a longer arm. The length is now the distance from the trailer's axles to the rear axle of my truck. In my case (short bed) and a 1' long Reese hitch, this adds 5' to the length. Now the system is 7400 lbs 2.73 feet from the rear pivot point (trailer axles) and is a 26' long lever. This places 2.73/26=10.5% of the weight on the truck and the remaining 89.5% of the weight on the trailer axles. So, 2.5% of the trailer weight was "transferred" back to the trailer wheels (185 lbs).
Consider my trailer. It weighs 7400 lbs and has 960 lbs on the tongue before hooking up. My trailer coupler is 21' from the center of the trailer axles. Since the tongue has 13% of the total weight, the system can be thought of as a simple arm from the center of the axles to the ball with the entire weight 13% of the way forward. In other words, it is like having a 21' arm with 7400 lbs 2.73 feet from the pivot point (center of my axles).
When hooked up without a WD hitch, it lifts up on the front axle of my truck because the 960# tongue weight is put behind my truck's rear axle, just like a see-saw. Now consider the case when the WD hitch is adjusted so the front axle does not change height when hooking up. The WD hitch effectively places all of the tongue weight directly over the rear axle. In some cases, the front axle drops a little, but let's just consider the case when it doesn't move at all.
Now with this scenario, the system (trailer) acts like a longer arm. The length is now the distance from the trailer's axles to the rear axle of my truck. In my case (short bed) and a 1' long Reese hitch, this adds 5' to the length. Now the system is 7400 lbs 2.73 feet from the rear pivot point (trailer axles) and is a 26' long lever. This places 2.73/26=10.5% of the weight on the truck and the remaining 89.5% of the weight on the trailer axles. So, 2.5% of the trailer weight was "transferred" back to the trailer wheels (185 lbs).
Senior Member
Joined: Jun 2010
Posts: 131
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From: West coast
After quite some thought and reading very confusing articles on how a WD hitch works and how much weight it transfers to the front axle and the trailer axles, I finally thought of an easy way to see what is happening.
Consider my trailer. It weighs 7400 lbs and has 960 lbs on the tongue before hooking up. My trailer coupler is 21' from the center of the trailer axles. Since the tongue has 13% of the total weight, the system can be thought of as a simple arm from the center of the axles to the ball with the entire weight 13% of the way forward. In other words, it is like having a 21' arm with 7400 lbs 2.73 feet from the pivot point (center of my axles).
When hooked up without a WD hitch, it lifts up on the front axle of my truck because the 960# tongue weight is put behind my truck's rear axle, just like a see-saw. Now consider the case when the WD hitch is adjusted so the front axle does not change height when hooking up. The WD hitch effectively places all of the tongue weight directly over the rear axle. In some cases, the front axle drops a little, but let's just consider the case when it doesn't move at all.
Now with this scenario, the system (trailer) acts like a longer arm. The length is now the distance from the trailer's axles to the rear axle of my truck. In my case (short bed) and a 1' long Reese hitch, this adds 5' to the length. Now the system is 7400 lbs 2.73 feet from the rear pivot point (trailer axles) and is a 26' long lever. This places 2.73/26=10.5% of the weight on the truck and the remaining 89.5% of the weight on the trailer axles. So, 2.5% of the trailer weight was "transferred" back to the trailer wheels (185 lbs).
Consider my trailer. It weighs 7400 lbs and has 960 lbs on the tongue before hooking up. My trailer coupler is 21' from the center of the trailer axles. Since the tongue has 13% of the total weight, the system can be thought of as a simple arm from the center of the axles to the ball with the entire weight 13% of the way forward. In other words, it is like having a 21' arm with 7400 lbs 2.73 feet from the pivot point (center of my axles).
When hooked up without a WD hitch, it lifts up on the front axle of my truck because the 960# tongue weight is put behind my truck's rear axle, just like a see-saw. Now consider the case when the WD hitch is adjusted so the front axle does not change height when hooking up. The WD hitch effectively places all of the tongue weight directly over the rear axle. In some cases, the front axle drops a little, but let's just consider the case when it doesn't move at all.
Now with this scenario, the system (trailer) acts like a longer arm. The length is now the distance from the trailer's axles to the rear axle of my truck. In my case (short bed) and a 1' long Reese hitch, this adds 5' to the length. Now the system is 7400 lbs 2.73 feet from the rear pivot point (trailer axles) and is a 26' long lever. This places 2.73/26=10.5% of the weight on the truck and the remaining 89.5% of the weight on the trailer axles. So, 2.5% of the trailer weight was "transferred" back to the trailer wheels (185 lbs).
Senior Member
Joined: Jan 2011
Posts: 432
Likes: 1
From: Chicago Area
Junior Member
Joined: Apr 2011
Posts: 6
Likes: 0
From: Highland Village TX
After quite some thought and reading very confusing articles on how a WD hitch works and how much weight it transfers to the front axle and the trailer axles, I finally thought of an easy way to see what is happening.
Consider my trailer. It weighs 7400 lbs and has 960 lbs on the tongue before hooking up. My trailer coupler is 21' from the center of the trailer axles. Since the tongue has 13% of the total weight, the system can be thought of as a simple arm from the center of the axles to the ball with the entire weight 13% of the way forward. In other words, it is like having a 21' arm with 7400 lbs 2.73 feet from the pivot point (center of my axles).
When hooked up without a WD hitch, it lifts up on the front axle of my truck because the 960# tongue weight is put behind my truck's rear axle, just like a see-saw. Now consider the case when the WD hitch is adjusted so the front axle does not change height when hooking up. The WD hitch effectively places all of the tongue weight directly over the rear axle. In some cases, the front axle drops a little, but let's just consider the case when it doesn't move at all.
Now with this scenario, the system (trailer) acts like a longer arm. The length is now the distance from the trailer's axles to the rear axle of my truck. In my case (short bed) and a 1' long Reese hitch, this adds 5' to the length. Now the system is 7400 lbs 2.73 feet from the rear pivot point (trailer axles) and is a 26' long lever. This places 2.73/26=10.5% of the weight on the truck and the remaining 89.5% of the weight on the trailer axles. So, 2.5% of the trailer weight was "transferred" back to the trailer wheels (185 lbs).
Consider my trailer. It weighs 7400 lbs and has 960 lbs on the tongue before hooking up. My trailer coupler is 21' from the center of the trailer axles. Since the tongue has 13% of the total weight, the system can be thought of as a simple arm from the center of the axles to the ball with the entire weight 13% of the way forward. In other words, it is like having a 21' arm with 7400 lbs 2.73 feet from the pivot point (center of my axles).
When hooked up without a WD hitch, it lifts up on the front axle of my truck because the 960# tongue weight is put behind my truck's rear axle, just like a see-saw. Now consider the case when the WD hitch is adjusted so the front axle does not change height when hooking up. The WD hitch effectively places all of the tongue weight directly over the rear axle. In some cases, the front axle drops a little, but let's just consider the case when it doesn't move at all.
Now with this scenario, the system (trailer) acts like a longer arm. The length is now the distance from the trailer's axles to the rear axle of my truck. In my case (short bed) and a 1' long Reese hitch, this adds 5' to the length. Now the system is 7400 lbs 2.73 feet from the rear pivot point (trailer axles) and is a 26' long lever. This places 2.73/26=10.5% of the weight on the truck and the remaining 89.5% of the weight on the trailer axles. So, 2.5% of the trailer weight was "transferred" back to the trailer wheels (185 lbs).