New Andersen WD hitch
A fellow camper bud showed me this. It's new and different. Anyone using one? Andersen WD hitches A U-tube video with the factory guy explaining it. You have to get past MR Truck doing his...
Forum Discussion
After the light bulb turned on from BenK and SoCalDesertRider :o Let's take a look at this again.
The issue noted is what is going on at the tow ball and the trailer ball coupler. First lets look at a conventional WD hitch. For picture sake I'm using mine. This applies to most any if not all WD hitches that use WD spring bars and a hitch head where the WD bars lock up in the hitch head.
Here is the Reese DC trunnion bar WD hitch
Now putting some force directions on the hitch and what is going on.
When you tighten the WD chains at the snap ups;
- The WD bars lock up in the hitch head and create a large torque force in the hitch head.
- The hitch shank transmits this torque force into the TV receiver, the receiver then applies WD on the truck.
- The WD bars and the hitch head are doing the work of the WD. Forces at the tow ball are the tongue weight pressing down along with the WD bar forces in the frame pushing down even harder on the top of the tow ball.
Now lets look closer at the tow ball area.
- When the TV pulls forward the tow ball if not already is fully seated in the front of the trailer ball coupler.
- The TT has rolling resistance and wind drag against it and the TV pulls the TT by the tow ball seated in the front of the ball coupler. In this condition there is clearance between the back side of the tow ball and the trailer ball coupler latch. The latch now is not under pressure as you tow forward down the level road, up hill or down hill unless the TT is rolling faster then the TV.
- When the TT brakes are applied and they lead the truck brakes the TV and TT connection stays tight and the ball stays seated in the front of the ball coupler.
If you look at the ball coupler it is made very heavy in the front portion to take all this towing loads the coupler is rated for. The safety latch on the coupler prevents the ball coupler from hopping off the tow ball. The coupler latch does get force against it when you back up or other more non normal towing events.
Now lets look at the Anderson system. This area is different and the tow ball area has very different conditions using this system.
I'm going to start with the hitch up process so folks can see what is occurring in stages.
Hook up TT to TV. The WD chains are slack at this point. For purposes of this part of the discussion the tongue jack may still be down or not. The tow ball is taking the dead weight of the TT tongue weight pushing down on it.
Now we start to tension the WD chains.
- As you crank up the tension on the nuts behind the urethane springs tension builds in the WD chains.
- The bottom of the tow ball shank starts to have a large force applied pulling the tow ball towards the TT. It also starts to create a torque into the hitch shank and starts the WD process.
- The TT is on wheels and so is the TV. The TV can rock back what ever small clearance exits in the transmission locking pawl. The TT can roll forward only limited by wheel chock or the tongue jack being down. Eventually the wheel chocks are removed and the tongue jack is lifted.
- As the WD chains are further tightened to create WD on the TV the TV and TT are pulled towards each other by the WD chains.
- The tow ball is now resting under force against the safety latch in the ball coupler. There is clearance now on the front of the tow ball between the ball and coupler.
- The WD chains are now fully tensioned, the tongue jack raised and the TT wheel chocks removed.
- This concept of WD uses high forces in the WD chains to create the WD. Since the TT is on tires of large diameter the forces in the chains are high enough they can actually pull the TT forward until the TT stops by the coupler latch being held back by the tow ball.
- As you tow forward you have 2 sets of forces going on in the WD chains. We already talked about the WD pulling on the chains from the urethane springs. And we talked about that the tow ball was seated up against the coupler latch.
- At the start of towing forward the truck starts pulling the TT. If the rolling resistance of the TT is less then the WD holding force in the WD chains, the chains are pulling the camper by the TV.
- We are now into the different forces going on up against the front of the TT. We have wind drag, going up hill, going down hill, towing level, and TV large acceleration to name a few.
- The larger force will win as to if the tow ball actually is towing the TT or the WD chains are towing the TT. If the rolling resistance is low enough on the TT, the WD chains force is high enough that the WD chains are towing the camper. If the rolling force against the TT are larger then the WD force in the chains, then the tow ball will shift from being up against the coupler latch to the front of the ball coupler.
The dynamics going on at the ball coupler and the coupler latch are very different with this hitch then the conventional WD hitch with spring bars.
When you are going slow the fact that the WD chains are pulling the camper is something I myself have just not yet accepted as a positive thing to do. And then there is the hard bounce of the back of the truck forces into the WD chains. The urethane spring brackets are really doing a lot of work. Anderson advertized this hitch as having shock absorbing characteristics. They are claiming this:
"Patented True Motion-Dampeningâ„¢ system -drastically reduces bounce"
Now I understand "I think" how they are doing this. They are towing the camper by springs. What would be ideal is to have someone from the ball coupler manufactures let us know what kind of loads the ball latch can handle.
If I missed something here or stated it not correct, please let us know.
I need help being convinced the issue at the ball coupler and at the urethane springs brackes are not going to be a long term problem.
Am I missing something that they are not a problem?
John
The issue noted is what is going on at the tow ball and the trailer ball coupler. First lets look at a conventional WD hitch. For picture sake I'm using mine. This applies to most any if not all WD hitches that use WD spring bars and a hitch head where the WD bars lock up in the hitch head.
Here is the Reese DC trunnion bar WD hitch
Now putting some force directions on the hitch and what is going on.
When you tighten the WD chains at the snap ups;
- The WD bars lock up in the hitch head and create a large torque force in the hitch head.
- The hitch shank transmits this torque force into the TV receiver, the receiver then applies WD on the truck.
- The WD bars and the hitch head are doing the work of the WD. Forces at the tow ball are the tongue weight pressing down along with the WD bar forces in the frame pushing down even harder on the top of the tow ball.
Now lets look closer at the tow ball area.
- When the TV pulls forward the tow ball if not already is fully seated in the front of the trailer ball coupler.
- The TT has rolling resistance and wind drag against it and the TV pulls the TT by the tow ball seated in the front of the ball coupler. In this condition there is clearance between the back side of the tow ball and the trailer ball coupler latch. The latch now is not under pressure as you tow forward down the level road, up hill or down hill unless the TT is rolling faster then the TV.
- When the TT brakes are applied and they lead the truck brakes the TV and TT connection stays tight and the ball stays seated in the front of the ball coupler.
If you look at the ball coupler it is made very heavy in the front portion to take all this towing loads the coupler is rated for. The safety latch on the coupler prevents the ball coupler from hopping off the tow ball. The coupler latch does get force against it when you back up or other more non normal towing events.
Now lets look at the Anderson system. This area is different and the tow ball area has very different conditions using this system.
I'm going to start with the hitch up process so folks can see what is occurring in stages.
Hook up TT to TV. The WD chains are slack at this point. For purposes of this part of the discussion the tongue jack may still be down or not. The tow ball is taking the dead weight of the TT tongue weight pushing down on it.
Now we start to tension the WD chains.
- As you crank up the tension on the nuts behind the urethane springs tension builds in the WD chains.
- The bottom of the tow ball shank starts to have a large force applied pulling the tow ball towards the TT. It also starts to create a torque into the hitch shank and starts the WD process.
- The TT is on wheels and so is the TV. The TV can rock back what ever small clearance exits in the transmission locking pawl. The TT can roll forward only limited by wheel chock or the tongue jack being down. Eventually the wheel chocks are removed and the tongue jack is lifted.
- As the WD chains are further tightened to create WD on the TV the TV and TT are pulled towards each other by the WD chains.
- The tow ball is now resting under force against the safety latch in the ball coupler. There is clearance now on the front of the tow ball between the ball and coupler.
- The WD chains are now fully tensioned, the tongue jack raised and the TT wheel chocks removed.
- This concept of WD uses high forces in the WD chains to create the WD. Since the TT is on tires of large diameter the forces in the chains are high enough they can actually pull the TT forward until the TT stops by the coupler latch being held back by the tow ball.
- As you tow forward you have 2 sets of forces going on in the WD chains. We already talked about the WD pulling on the chains from the urethane springs. And we talked about that the tow ball was seated up against the coupler latch.
- At the start of towing forward the truck starts pulling the TT. If the rolling resistance of the TT is less then the WD holding force in the WD chains, the chains are pulling the camper by the TV.
- We are now into the different forces going on up against the front of the TT. We have wind drag, going up hill, going down hill, towing level, and TV large acceleration to name a few.
- The larger force will win as to if the tow ball actually is towing the TT or the WD chains are towing the TT. If the rolling resistance is low enough on the TT, the WD chains force is high enough that the WD chains are towing the camper. If the rolling force against the TT are larger then the WD force in the chains, then the tow ball will shift from being up against the coupler latch to the front of the ball coupler.
The dynamics going on at the ball coupler and the coupler latch are very different with this hitch then the conventional WD hitch with spring bars.
When you are going slow the fact that the WD chains are pulling the camper is something I myself have just not yet accepted as a positive thing to do. And then there is the hard bounce of the back of the truck forces into the WD chains. The urethane spring brackets are really doing a lot of work. Anderson advertized this hitch as having shock absorbing characteristics. They are claiming this:
"Patented True Motion-Dampeningâ„¢ system -drastically reduces bounce"
Now I understand "I think" how they are doing this. They are towing the camper by springs. What would be ideal is to have someone from the ball coupler manufactures let us know what kind of loads the ball latch can handle.
If I missed something here or stated it not correct, please let us know.
I need help being convinced the issue at the ball coupler and at the urethane springs brackes are not going to be a long term problem.
Am I missing something that they are not a problem?
John
