Andersen UNDERSLUNG WD Hitch Experiment

[Mikey]

Opening disclaimer - your experience may differ! I offer this only in the hope that it helps current or future Andersen users.

Okay. I've towed my White Hawk 28DSBH with the Andersen weight distribution hitch for a year now. I remember picking up the trailer and driving 105 miles home on the interstate - the Andersen tamed the winds and ignored the semis zooming past. There was no sway, little bounce or chucking, and in general it was a relaxing first experience. Every day since has been the same thanks to Andersen's superb anti-sway properties.

When I finally weighed my setup, however, I was disappointed. I was over my rear axle GAWR by 50 lbs and getting little front axle load restoration. I had to crank down the tensioning nuts on the hitch to 12 threads showing, and the urethane springs were so compressed that I wondered whether they'd hold up under continued towing. And all that only got me to 47% FALR. It seemed that what many had reported on the boards was true - the Andersen struggled with weight distribution on larger, heavier trailers.

I almost gave up on the Andersen - in fact, I actually bought a BlueOx SwayPro to replace it. But when I learned that BlueOx wanted me to turn off my F150's electronic sway control while using the SwayPro, and as I read complaints by owners about the SwayPro's spring bars bottoming out on speed bumps, etc., I decided it wasn't for me. I returned it without opening it.

I thought about the Equalizer, but the Andersen still occupied my thinking. I hated to gamble on losing that comfortable towing experience, so I decided to do some troubleshooting. First, I reinstalled the hitch and discovered that I'd been towing about 1.5 inches nose down. Moving the ball up one place in the shank solved that. Then I focused upon the impact of the White Hawk's underslung coupler on the hitch setup. Andersen says it doesn't matter, but as the first picture shows, the weight distribution chain ends up diving toward the triangle plate under the hitch ball, throwing off the alignment of the chain with the urethane bushings on the far side of the chain tube. As Andersen advises maintaining this alignment to maximize performance, I couldn't help but wonder if this was degrading my hitch's WD abilities.

The other thing noticeable in the first photo is that the hitch brackets on the a-frame roll up and forward from underneath once placed under load. Using the set screw and ensuring proper torque on the bracket bolts doesn't prevent this. In fact, the hitch brackets slightly dimple the frame where the bolts come to rest against it, allowing even more rotation forward. The brackets reach a permanent location after their initial slippage, but because they've slid up and forward, they further degrade chain alignment AND add slack to the WD chains, meaning that more threads showing are need achieve proper FALR. If you slide the brackets back to the same spot and reinstall, the same thing happens again. If you slide them TOO far back to anticipate slippage, then you can't get enough bolt showing through the spring and washer to thread the tensioning nut.

It became clear to me that Andersen's "optional" welding of the brackets to the frame wasn't optional at all, at least not for me. But if I was going to weld the brackets in place, I wanted to solve the WD chain alignment problem at the same time. I needed different, longer brackets to drop the chain tube low enough that the WD chains could run straight and true to the triangle plate without diving.

Andersen makes their frame brackets in several sizes. For my trailer I was using their 3/4/5/6" bracket, which is called for with the White Hawk's 5" frame. When I explained to their tech Jason what I had in mind, he took one of their 8" bracket sets and drilled special 5" mounting holes into it and sent it to me at no charge. As you see in picture 2, that bracket drops the chain tube another 2", compensating for the underslung coupler and almost perfectly aligning the chain tube and triangle plate beneath the hitch ball. I had these brackets welded in place and hit the road for testing.

The Andersen now delivers all the FALR (77%!) I need to keep my trailer and truck perfectly level and stay well within front and rear axle GAWRs. I towed for an hour today with 14% tongue weight, and the Andersen still has masterful anti-sway properties, but anti-bounce is even better and weight distribution is now a cinch. I have just 7 threads showing on the WD chain bolts.

One other tweak I made to Andersen's standard setup was the addition of another set of washers BETWEEN the chain tube and urethane spring. This reduces the number of threads need to reach my proper FALR by one and better protects the spring when under heavy compression. BTW, Andersen sent me those washers for free as well, as well as a spare set of urethane springs. Their service is top notch.

I suggested to Jason at Andersen that they consider packaging these mods as a special underslung coupler model. Don't know if they will but I'm sure they'll work with you if you want to try what I've done.

For those of you already getting what you need out of your Andersen, feel free to ignore me. But if you're in the same boat I was or are considering buying an Andersen, I hope this post is useful. Cheers.

[motorbreath]

I made sure to buy the Blue Ox Sway Pro with the underslung hitch option...zero problems with the bars clearing the ground towing my 28BHBE. In fact, I have never heard of anyone having that issue.

While the Anderson WDH seems very desirable from a weight and simplicity perspective, do a force balance on the properly setup system and you'll see that it puts a significant amount of force on the back of the hitch ball. There are schematics of this available online if you do a search. I think a traditional WDH is likely more appropriate for heavier trailers.

[Mikey]

Originally Posted by motorbreath

I made sure to buy the Blue Ox Sway Pro with the underslung hitch option...zero problems with the bars clearing the ground towing my 28BHBE. In fact, I have never heard of anyone having that issue.

While the Anderson WDH seems very desirable from a weight and simplicity perspective, do a force balance on the properly setup system and you'll see that it puts a significant amount of force on the back of the hitch ball. There are schematics of this available online if you do a search. I think a traditional WDH is likely more appropriate for heavier trailers.

Motorbreath, so glad the Blue Ox works for you. Happy camping!

[RogerR]

I also had a problem with the Andersen brackets creeping on me. I even bought a 24 inch bar to really crank the bolts and they still tilted.

On the other hand, when they are tightened properly they really work well.

So now before our first outing I am looking for a welder to make them permanent.

[2nOZ]

Great article Mikey. Thanks for sticking with it and sharing this information. I am still happy with mine and the way it works for our combination. So far my brackets have not slipped and the bottom is angled forward but my installation directions indicate that is the way they should be. I will check mine tomorrow because I think my chains angle down towards the plate. The pics really one see what is being explained.

[Mikey]

Originally Posted by 2nOZ

Great article Mikey. Thanks for sticking with it and sharing this information. I am still happy with mine and the way it works for our combination. So far my brackets have not slipped and the bottom is angled forward but my installation directions indicate that is the way they should be. I will check mine tomorrow because I think my chains angle down towards the plate. The pics really one see what is being explained.

Hey Oz, thanks for the kind words. Yup, they are supposed to rotate forward on install, but mine kept slipping a bit beyond the install point and then slightly dimpled the frame where the bolts eventually came to rest. The dimples kept them from slipping further but they also increased the bracket angle and shortened the distance between the brackets and hitch, both of which degraded performance somewhat. If your brackets have come to rest in a good spot and if the ride and weight distribution are working well, you're in fine shape. I'm really glad you're enjoying the hitch!

[Rustic Eagle]

It may just be the vantage point from which the pics were taken..... but the pics peaked my curiosity a little.

The forward tilt-angle of the shank/ball housing assembly seems to be a little aggressive (?). Is the TV receiver pin-box flexing upward as well? I reviewed the Anderson installation manual and did notice there wasn't a means for adjusting the tilt angle of the ball housing on the shank.

Hard to tell...., but could the top outer edge of ball housing possibly come in contact with the bottom surface of the TT ball coupler under certain irregular ground surface conditions between the TV & TT?

I've not had the opportunity to view the Anderson WDH installed first hand, thus the questions.

Bob

[Mikey]

Originally Posted by Rustic Eagle

It may just be the vantage point from which the pics were taken..... but the pics peaked my curiosity a little.

The forward tilt-angle of the shank/ball housing assembly seems to be a little aggressive (?). Is the TV receiver pin-box flexing upward as well? I reviewed the Anderson installation manual and did notice there wasn't a means for adjusting the tilt angle of the ball housing on the shank.

Hard to tell...., but could the top outer edge of ball housing possibly come in contact with the bottom surface of the TT ball coupler under certain irregular ground surface conditions between the TV & TT?

I've not had the opportunity to view the Anderson WDH installed first hand, thus the questions.

Bob

Bob,

Funny that you mention that, because after feeling celebratory about finally getting this hitch optimized, I noticed the same thing. I did inspect both the coupler and the top outer edge of the ball housing after towing over 50 miles in mixed conditions, and there's no evidence of contact. But I still don't like looking at it. The TV receiver pin box itself isn't flexing upward but there's a lot of room around all sides of the shank pin inside the box. I'm wondering about it now and what I should do to remedy it, if anything. Looking at the pics I was considering dropping the ball housing down one setting in the shank to see whether that helps, although it'll put my trailer a wee bit nose down again. Any advice is greatly appreciated.

[Mikey]

Originally Posted by Mikey

Bob,

Funny that you mention that, because after feeling celebratory about finally getting this hitch optimized, I noticed the same thing. I did inspect both the coupler and the top outer edge of the ball housing after towing over 50 miles in mixed conditions, and there's no evidence of contact. But I still don't like looking at it. The TV receiver pin box itself isn't flexing upward but there's a lot of room around all sides of the shank pin inside the box. I'm wondering about it now and what I should do to remedy it, if anything. Looking at the pics I was considering dropping the ball housing down one setting in the shank to see whether that helps, although it'll put my trailer a wee bit nose down again. Any advice is greatly appreciated.

Bob, I just went and measured the interior dimensions of my 2" hitch receiver. Side-to-side is 2 1/16", but vertically it's just shy of 2 1/4". That's making for a lot of slop. I bought my truck used last year and the drop shank stinger has always been loose in the receiver - I don't think the Andersen is the culprit. I think the play in the receiver is just more obvious now that the Andersen is installed well enough to deliver significant upward WD force. I don't know if the remedy is a new TV hitch or something as simple as the Roadmaster Quiet Hitch. Thoughts?

[Rustic Eagle]

The 1/4" is to much slop in the pin box in your case....., it just amplifies the shank/ball housing tilt problem the further the hitch ball distance is from the pin box. IMO the Roadmaster product isn't a solid fix for your particular WDH condition.

I would consider the merit of steel shim(s) (slip fit) within the pin box (possibly top & bottom) minimizing vertical shank movement when the hitch pin is in place. Also, if your pin box clearance holes are showing signs of "elongating", this condition isn't doing you any favors. Elongated holes are the result of using hitch pins that have the 'bend' in one end...., using a straight hitch pin (no bends) is more desirable.

As I mentioned earlier, I was surprised that the Anderson WDH doesn't have a means to allow for some degree of ball housing tilt adjustment.., IMO this common WDH feature is important with heavier tongue weight applications because of the increased 'vertical-torque' forces transferred through any WDH assembly and TV receiver pin box. Having a means of ball mount (housing) tilt adjustment also can compensate for minor pin box slop.

Lowering the ball housing on the shank won't reduce the present degree of forward shank/ball housing assembly tilt.

Just for grins, before you disconnect your TT (WDH engaged) measure the distance between the top of the receiver pin box (end of) and the bottom of your bumper, then measure again with the TT disconnected. The difference is pin box flex....., under 1/4" flex is ideal IMO.

Bob

[Mikey]

Originally Posted by Rustic Eagle

The 1/4" is to much slop in the pin box in your case....., it just amplifies the shank/ball housing tilt problem the further the hitch ball distance is from the pin box. IMO the Roadmaster product isn't a solid fix for your particular WDH condition.

I would consider the merit of steel shim(s) (slip fit) within the pin box (possibly top & bottom) minimizing vertical shank movement when the hitch pin is in place. Also, if your pin box clearance holes are showing signs of "elongating", this condition isn't doing you any favors. Elongated holes are the result of using hitch pins that have the 'bend' in one end...., using a straight hitch pin (no bends) is more desirable.

As I mentioned earlier, I was surprised that the Anderson WDH doesn't have a means to allow for some degree of ball housing tilt adjustment.., IMO this common WDH feature is important with heavier tongue weight applications because of the increased 'vertical-torque' forces transferred through any WDH assembly and TV receiver pin box. Having a means of ball mount (housing) tilt adjustment also can compensate for minor pin box slop.

Lowering the ball housing on the shank won't reduce the present degree of forward shank/ball housing assembly tilt.

Just for grins, before you disconnect your TT (WDH engaged) measure the distance between the top of the receiver pin box (end of) and the bottom of your bumper, then measure again with the TT disconnected. The difference is pin box flex....., under 1/4" flex is ideal IMO.

Bob

Thanks, Bob. I use a straight hitch pin, so there's one positive at least.

I'll follow your advice to measure and rule out unacceptable receiver flex. I'll also try steel shims and see how I do. I'll update this thread when done so folks can learn from my experience...gotta give back to the forum! Thanks again for taking the time to help, and for doing so in a kind, mentoring way.

One more question for you...it looks to me like if I eliminate the hitch slop I'll get even more WD out of the setup, as that upward force on the shank stinger will be more completely transferred into the hitch receiver. As I'm already at desired FALR, that means I may have to dial back the tension on my WD chains a thread or so. Does this make sense (I know I'll need to confirm at a scale)?

[Rustic Eagle]

Originally Posted by Mikey

snip...... As I'm already at desired FALR, that means I may have to dial back the tension on my WD chains a thread or so......snip

Possibly, and as you mentioned a scale visit will confirm. A "slight" tilt in the ball housing (mount) under loaded/engaged conditions is common with most WDH applications, even after dialing in the WDH adjustments.

My initial concern upon viewing your pics was the increased possibility of your ball housing coming in contact with the TT coupler, and/or the functionality of the internal locking collar within the TT coupler being compromised under certain conditions.

Good move on using a straight hitch pin.

Bob

[Rustic Eagle]

Originally Posted by 2nOZ

snip...... I will check mine tomorrow because I think my chains angle down towards the plate. The pics really one see what is being explained.

If you could post a side-view pic of your Anderson WDH it would be interesting to see the degree of ball housing tilt you are experiencing with your particular TV/TT combination.

Thanks in advance....

Bob

[Mikey]

Originally Posted by Rustic Eagle

Possibly, and as you mentioned a scale visit will confirm. A "slight" tilt in the ball housing (mount) under loaded/engaged conditions is common with most WDH applications, even after dialing in the WDH adjustments.

My initial concern upon viewing your pics was the increased possibility of your ball housing coming in contact with the TT coupler, and/or the functionality of the internal locking collar within the TT coupler being compromised under certain conditions.

Good move on using a straight hitch pin.

Bob

No credit to me...the Andersen comes with a straight pin, although now I'm considering one of those special pins designed signed to help eliminate slop.

Here are the two best before and after pics of the hitch with WD disengaged and then engaged. You can see how the gap between the ball housing and TT coupler closes some due to the slop in my receiver. I think (hope) that if I eliminate that I really will have a reliable setup. Funny, in these photos the gap doesn't seem radically smaller when WD is engaged...

[2nOZ]

Mikey, thanks for the pics. I looked at the angle of my chains today and they are not level like yours. They do descend towards the plate. I also have a lot of slop in my receiver. Most of the slop comes from the class four to class five insert. It's quite a bit. Not a lot between the hitch unit and sleeve. Not sure what is meant by a straight pin vs a curved pin. Please let me know what rectifies the slop. I will probably have to do the same thing.

[Mikey]

Originally Posted by 2nOZ

Mikey, thanks for the pics. I looked at the angle of my chains today and they are not level like yours. They do descend towards the plate. I also have a lot of slop in my receiver. Most of the slop comes from the class four to class five insert. It's quite a bit. Not a lot between the hitch unit and sleeve. Not sure what is meant by a straight pin vs a curved pin. Please let me know what rectifies the slop. I will probably have to do the same thing.

Oz, Bob was referring to the pin that holds the hitch in the receiver. Andersen provides a straight pin so we're okay there. I'll definitely follow up with info on how I solve it. One approach I'm considering is to have my local welder lay down some welds or weld a shim to the top of the shank stinger so that when I insert it in the receiver it's snug and eliminates all upward travel. I can always have him grind the welds down if I ever switch tow vehicles or WD hitches. This way, I won't be constantly messing with shims or aftermarket hitch tighteners. The stinger will be the ideal fit for the receiver and I won't have any additional steps to worry about, just insert, secure and hitch up. Since your slop is between the sleeve and receiver, you might benefit from doing the same thing to the sleeve to snug it into the receiver. Again, I'll let you know how it all turns out, with pics if I can.

[Murff]

Look forward to the conclusion, Mike!

Thanks!

Murff

[Mikey]

Originally Posted by Murff

Look forward to the conclusion, Mike!

Thanks!

Murff

You got it, Murff. I did some further examination of the situation tonight as I noodle on a solution. I measured how much variation in ball height is created by the receiver slop. It's pretty amazing...from 26 1/4" to 27 1/4", a full inch! I then experimented with 2 washers as stand-ins for an eventual shim, and they eliminated the upward travel of the hitch entirely, so that was promising. I'll probably try to fabricate a shim this week and test it out towing over the weekend. I also ordered a Stowaway hitch tightener to use in conjunction with the shim.

As far as I can tell, the receiver isn't damaged, cracked, or stretched out. It's simply that the initial 1" of the receiver is slightly flared vertically to allow for easy entry of the hitch stinger, and then it narrows for the rest of the receiver's length. The PROBLEM is that the receiver is 6" long but the stinger on the Andersen shank only penetrates 3.5" before it must be secured with the hitch pin. In other words, a longer stinger would go a long way towards eliminating the vertical slop in my setup.

More to follow...

[Mikey]

The Stowaway hitch tightener arrived today. It's much heavier and more solidly built than I anticipated, especially compared to the Roadmaster Quiet Hitch, which I also bought but am returning.

I fit it to the hitch and torqued it to the recommended 60 ft lbs and it was rock solid. I'm hoping that placing a shim between the stinger and receiver and then installing the Stowaway will create a sound solution - the Stowaway will ensure the shim stays in place and the shim will prevent any slop that might stress the Stowaway. The Stowaway LOOKS like it could do the job on its own and I've read several reviews to that effect, but I think Bob is right to suggest shims. I'm going to fully set it up under load Saturday for a weekend outing and will post pics and results from the trip. Slop be gone (wish me luck)!

[Murff]

Rots-a-ruck!

Murff