Good and Bad about Blue Ox Sway Pro

[Rescue16]

I just purchased a 2013 Cougar 32RBK travel trailer and I am towing it with a 2006 Ford F350 Crew Cab With the 6.0 Powerstroke. I am looking at getting the Blue Ox Sway Pro and would like to here the good and bad about this WD/Sway control. With my previous RV and vehicle (21SS Shamrock Hybrid and Ford E250 Conversion van) I used the Equalizer and all the experience was great it was really noisy.

Thanks in advance for taking a moment to tell me the good and bad!!

[Ron_Gratz]

BenK wrote:
Progressive....bats arr tappered...therefore progressive as they bend more

Ben, being tapered does not make a bar "progressive".

A WD bar is a simple cantilever beam -- and it has to obey the basic laws of physics.
The equation for deflection of a tapered cantilever is given in Tapered Beam Bending Equation and Calculator.

As you can see, the relationship between deflection and load is linear.
If you increase load, "F", by x%, the deflection, "d", increases by x%.
In order for the beam to be "progressive", the relationship would have to be non-linear.

Different axis of rotation centers of ball vs bars....plus different plans

I don't know the significance of this. Can you elaborate?

Ron

[BenK]

Progressive....bats arr tappered...therefore progressive as they bend more

Different axis of rotation centers of ball vs bars....plus different plans

[JBarca]

Ron,

I knew you could not stay away from this post...:C Thanks for the info. Much appreciated.

Your post still has me reading... I have not been able to find Andy's "Why is your hitch crooked?", in the Summer 2010 edition of AIRSTREAM LIFE magazine. However I did run into a 2011 post talking about it with Wes, Ron and my spring bar data... I must of been out camping then.... Missed a good hitch talk. Best Weight Distributing Hitch with Sway Control?

For me, the jury is still out on how effective the tilted hitch head concept combined with thinner than normal WD bars and drum wrapped chain hook up brackets is in mitigating sway.

However Blue Ox, a stand up company with good quality products changed there underlying working principle of their only WD hitch.

The older Sway Pro like this


To the new Sway Pro like this:


The older unit at least had adjustable friction in the hitch head. The new unit is totally relying on this steering effect to create a level of anti sway control. This sort of leaves us with ???

In regards to the progressive spring rate, Blue Ox "might" have a progressive force increase from the drum style chain bracket. In order the prove or disprove this to myself, I need to do a layout of the chain wrap action on a drum in regards to the vertical lift of the WD bar per angle of hitch head rotation. If the vertical displacement of chain pull increases with WD bar swing with an increase in angle between the TV and TT as viewed from the top, then the WD bar is being lifted progressively more on their rotary chain bracket then a conventional snap up over center chain bracket. I need a good hitch experiment to stimulate my curiosity. 🙂

Thanks

John

[Ron_Gratz]

I think the title for this thread should be: Good, Bad, and Uncertain about Blue Ox Sway Pro

IMO, there is not enough information or experience to say what is good and what is bad, but I sure have my doubts as to how effective the hitch will be at controlling sway.

In particular, I see no theoretical basis for believing the rearward tilt of the ball mount will make any significant contribution to sway control.
With due respect to Andy Thompson, I do not see any connection between the effects of bicycle head-tube angle on bicycle stability and the effects of WDH tilt on sway control.
The combination of bicycle head-tube angle and rake result in some amount of caster for the bicycle's front wheel. However, I see nothing remotely similar to a caster effect resulting from the rearward tilt of a WDH.

Andy goes into a much more detailed discussion of his views on the effects of ball mount tilt in an article titled, " Why is your hitch crooked?", in the Summer 2010 edition of AIRSTREAM LIFE magazine.
He correctly describes how ball mount tilt will cause the height at the tip of an unloaded WD bar to change as the bar changes direction with respect to the TV.
He also describes how the horizontal angle between WD bar and TV centerline will affect how load is applied to the TV. Specifically, when a WD bar is non-parallel to the TV's longitudinal centerline, there will be a component of bar-induced torque which tends to rotate the TV about its roll axis, in addition to the pitch-axiz torque which causes load on the front axle to increase and load on the rear axle to decrease.

Andy explains how the roll-axis torque will affect the TV's stability. However, his discussion pertains to TV/TT articulation angles of 22 degrees and greater. He mentions an emergency maneuver such as a sudden lane change. Andy's company, Can-Am RV Centre, conducts slalom-course testing with a variety of TV/TT combinations (see the "Towing Videos") on their web page.

At the end of the AIRSTREAM LIFE article, Andy states:

Beyond making the tow vehicle much easier to control in an emergency maneuver, the ball mount angle assists with directional stability going straight down the road at highway speeds.---

I don't know if Andy has test data to support the second part of this statment, or if he is using the following reasoning for support.

He goes on to state:

---Even in small degrees of direction change, the torsion bar on the outside of the turn gains tension much faster than the bar on the inside loses tension. This is because as a torsion bar bends it requires progressively more effort to bend the same distance.---

Again, with due respect, Andy got it wrong here. It is correct that the curvature of the outside bar is increasing, although relatively slowly. It is not correct that as a bar bends it requires progressively more effort to bend the same distance. There is no "progressive" spring rate for a WD bar. For all practical purposes, the spring rate remains constant. If one could measure accurately enough, the spring rate (incremental load divided by incremental deflection) actually would decrease with deflection because that's a fundamental characteristic of steel as it approaches its elastic limit. For a WD bar to be "progressive", it would have to be built like a leaf spring or have a "helper" spring attached.

The bar tip follows a circular path in an inclined plane which is perpendicular to the trunnion axis. When the trailer is articulated a few degrees, the tip of the outside bar moves closer to the low point of its orbit. Since the bar already is quite close to the low point, there is relatively little increase in the load on the bar.
The tip of the inside bar also is close to its low point, but is moving away from its low point and is losing load at small rate.

But, as they say on the infomercials: Wait, there's more. As stated before, the WD bars not only generate pitch-axis torque on the TV, they also generate roll-axis torque. Since the outside bar is moving toward being parallel to the TV's centerline, its roll-axis torque moment arm is decreasing toward zero. That means its CCW (when viewed from rear) roll torque is decreasing towards zero.
OTOH, the inside bar is swinging away from the TV's centerline, so its roll-axis moment arm is increasing. Although the load on the bar is decreasing, the moment arm is increasing at a faster rate, and the inside bar's CW roll-axis torque continues to increase.

Roll-axis torque is an important consideration because it generates increasing load on the TV's outside tires. This results in a phenomenon similar to roll steer, scroll down to "Roll Steer". Roll steer can make the TV steer to the right when the TT swings left, thereby decreasing the tendency to sway. A friction-based sway control also has a steering effect which results from yaw-axis torque.

HOWEVER, the foregoing is not an arguement in favor of the benefit of a large amount of ball mount tilt versus zero tilt. At small articulation angles which might be associated with "sway", the WDH-induced roll torque is virtually independent of ball mount tilt. In fact, the torque decreases as rearward tilt increases. So, it appears there is no basis for the claim that a relatively large rearward tilt of the ball mount gives improved sway control.

Getting back to Andy's AIRSTREAM LIFE article -- he concludes by stating:

Another way to think about it is to picture the forks of a bicycle or motorcycle. They always angle backward at the top. This is why you can ride a bike with no hands. If the forks on a bike were completely vertical, you would not be able to ride it with "no hands" -- it would be too unstable. The angle on a ball mount provides a similar function as forks on a bicycle.

Okay, let's assume that what Andy says about the effect of head-tube angle on the stability of a bicycle is true. Let's assume, when riding "no hands", you can control the stability of a bicycle by shifting your weight side to side.
A table in Andy's article shows that, for 22 degree articulation, a vertical ball mount generates more side to side load shift than does a rearward ball mount angle.
If the "similar function" between bicycle forks and ball mount angle is to cause a side-to-side load shift, the vertical ball mount did a better job for the 22 degree test case.
For small articulation angles of the magnitude that might be associated with the onset of sway, there is virtually no difference between vertical ball mount and 15 degrees of rearward tilt.

So, IMO, there is no basis for the claim that increased rearward tilt will lead to better sway control.
As far as I know, there is no published test data to support the claim that ball mount tilt or trunnion axis tilt can eliminate or reduce the likelihood of sway.
I think there will continue to be much uncertainty about such claims.

Ron

[JBarca]

Rescue16 wrote:

I have a short bed truck with a ARE Deluxe Walkin Cap which does away with the tailgate on the truck but the ARE Cap weighs almost 450 lbs and a Carry probably 600lbs of gear in the back of the truck when towing

Rides a little rough is kind of hard to explain. I towed a 6K TT no weight dis or sway control for the dealer on a 25 mile trip on the highway and did not even know the RV was back there it was a smooth ride the same road with my trailer you could feel every bump and the front end of the truck almost seemed like it was bouncing somewhat. Will try and answer the rest of the questions in a couple of weeks although it is going to take a while for me to get to scales. Thanks for any input or thoughts

Hi Rescue,

I see some things in your post now that point to a possible setup issue that I too found with my F350.

The next time you hitch up the camper and ready to roll, look at the rear helper springs (overloads). When I first started towing with this truck I set the WD to return the front end to come back to unhitched height & weight. At this time my camper only had a 1,200# loaded TW as that was all my prior 2500 Suburban could handle. The F350 did not ride well in this configuration. Here I have 1.5 times the truck, more wheel base, lots of extra axle capacity and the Burb towed smoother than the F350. It felt like the back of the truck was wandering up and down left to right.

I towed with it for a short while this way until I ran into a few things unique to this truck rear suspension. I added more bed weight and loaded the camper more so my TW was now up towards 1,400# with about 500# in the truck bed.

Then I tweaked the WD to lighten up just a little on the front end. This allowed the back of the truck to just kiss rear helper springs. OMG... there was a global shift in left to right stability. Like a different truck. The truck was now stable left to right. The rear helper springs are acting like a roll bar. Those 1 ton springs way high up in the suspension are, well soft and soggy. They allow the heavy TW camper to rock the truck.

Now I have even more TW and a little more stuff in the bed, still kissing only on the top rear helper spring and she rides even better. My front end is about 100# lighter than unhitched.

Here is the front spring, no where near the frame bracket yet


Here is the rear one, kissing it.


In my case I knew my weights so I knew the actual TW and front and rear axle weights so I could figure out what was going on.

When you get your weights, make sure you get all 3 set, all axle by axle.

1. TV & TT hitched with WD engaged.

2. Don't move the truck, drop the tongue jack, drop the WD bars, left the jack down and let the raw tongue hang on the ball. Take a weight.

3. Hitch up the WD bars, drive off, drop the TT and drive just the truck on.

Again, the front and rear truck axle will have their own separate scale, and both TT axles will be on one scale. This is a 3 segment truck scale. like this


From those 3 sets of weights you can sort out where you are at and your loaded TW. Just make sure you have all your stuff in the camper and truck and a full tank of fuel.

You can then check your WD bars are sized right and how the truck is adjusted. Also look at the helper springs.

Hope this helps and good luck

John

[Rescue16]

JBarca wrote:
Hi Rescue

Maybe can help. I looked up your camper.

http://www.keystonerv.com/cougar-xlite/ Nice camper, congrats.

That 34' 7" long camper starts out at 7,401# dry with a 750# dry tongue weight. That comes out to be 750/7401= 0.101 or X100 = 10.1% dry tongue weight. That is a very light tongue weight for a camper of that length. That means when you load it, you would really want to get it more in the 13% to 15% range. Since you have 1,599# of cargo capacity, if you added 1,200# of stuff, (not hard to do in 35 feet) this could put you up at 8,601# loaded GVW. At 13% loaded tongue that is 1,118# and at 15% that is 1,290# loaded tongue weight.

Tell us what "ride is a little rough" feels like?

In this case a trip to the truck scales can really help sort this out. Need 3 set of weight in progression. TT & TV hitched with WD on, TV and TT hitched no WD (drop the chains) and then truck only. All axle by axle weights.

If you are at 1,000# WD bars now, and you should be up in the 1,100 to 1,200# TW range, you really do not want to go lighter bars.

I have some experience with your truck suspension, mine is a 05, yours and 06 but they are close.

Also tell us, what do you have in the truck bed when towing the TT? and where is it in relation to the rear axle, on top, in front or behind?

Any chance of providing fender heights unhitched and then hitched with the WD bars snapped up?

Do you haul fresh water to camp and if so where is the tank in relation to the TT axles, on top, in front or behind?

Hope this helps

John

John all good questions will take me a few weeks to get back to the RV and get it hooked up with my crazy work schedule. Actual weight of items inside of RV is more like 700lbs with most of the weight in the back of the RV except for maybe 200lbs up front. I haul about 3 gallons of water Fresh water just enough to flush the toilet while on the road. I have a short bed truck with a ARE Deluxe Walkin Cap which does away with the tailgate on the truck but the ARE Cap weighs almost 450 lbs and a Carry probably 600lbs of gear in the back of the truck when towing. I have changed out the shocks and put on the Rancho rs9000xl adjustables.

Rides a little rough is kind of hard to explain. I towed a 6K TT no weight dis or sway control for the dealer on a 25 mile trip on the highway and did not even know the RV was back there it was a smooth ride the same road with my trailer you could feel every bump and the front end of the truck almost seemed like it was bouncing somewhat. Will try and answer the rest of the questions in a couple of weeks although it is going to take a while for me to get to scales. Thanks for any input or thoughts

[DMza061403]

I love the system. No troubles once you dail it in as with any system.

[BarneyS]

John,
Thanks for the explanation! I too now get it! :B

By the way, we'll be over in your neck of the woods next weekend to see our granddaughter graduate from Denison U. at Granville. No trailer though.
Barney

[JBarca]

Mike Up wrote:
OK I FINALLY SEE the affect as I was reading an old email from one of their engineers.

He stated this new head offers supperior sway control and now I see why. It finally just dawned on me and it's very simple but very effective.

First as mentioned, the spring bars bend much more than any other makers bars and Blue Ox took advantage of this.

They angled their head more than other heads because they can get away with it because the bars will bow, while other bars would be straighter interfereing with ground clearance and the such.

The steep angle, which is greater than the Reese trunnion, Equalizer brand and even Blue Oxs old head, allows the bar to swing up when pushed outward and load more, putting more push on that side, while the other bar swings inward and down, putting less force than normal, allowing the other side to push toward it, in that direction.

This force isn't done by other system because they don't have the steep head downward tilt that the Blue Ox head has, which is allowed by the bars ability to bend up and not have inteference issues.

There ya Go. Now you got it. While I can see it, and understand the bicycle fork example, I have no good handle on how effective it is. Have not yet thought of a way to calculate the force correction to compare it to the more traditional friction approaches, which is more straightforward.

If my curiosity gets the best of me (has before) I may take one of my old hitches, tilt the head back 15 degrees and go play.

The Blue Ox rotary chain bracket also creates more trunnion bar end lift (force) when the TT & TV becomes more off - center than the traditional chain hanging on a hook. The Blue Ox chain is wrapping around a drum so to speak as the chain and WD bars swings towards the TT. The chain will shorten in vertical length more than a chain hanging off a snap up center hook where the chain only pivots. The swinging chain on a high up pivot has a shallower angle to the chain less than chain wrapped around a drum, which has more mechanical advantage in this case. Granted this WD bar lift action is small however, an increase in spring force will help the steering effect more that they are claiming.

Good luck and let us know if you get one.

John

[LarryJM]

Mike Up wrote:
Thanks John. I completely agree about what you're saying. The people I talked with at Blue Ox previously, swear that the new Sway Pro controls sway much better than the old with the friction control bolts. They are really proud of the system and proved that point to me, as I spoke to an engineer and the VP and there were several posts.

Unfortunately, my dealer wouldn't pony up for an entire new system and only replaced the obvious broken parts. Now that I'm seeing more damage that couldn't be seen until the system was pulled and dismantled a few times, I'm think I'm done with it. I just don't trust the Reese Dual Cam parts as there maybe other unforseen stresses that could cause failure.

Besides if it was all new, I wouldn't trust it not to bind up again. I wish I would had bought a new Equalizer or Blue Ox system with the new trailer. To many issues with the Dual Cam bars contacting the cam arm lobe brackets and mainly due to Reeses direction saying 5 links are needed which doesn't provide enough clearance.

Thanks again.

Mike,

IMO I think the Equal-i-zer might be the system you would like. While a fine system the Reese just has too many parts and quirks in setting it up like placement of the brackets on the frame and drilling holes, etc. for my liking. I went thru the same process to some extent when I changed from my old single "friction bar" system for our new trailer. Neither the Blue-Ox Pro or Anderson were available at that time, but I still would have chosen the Equal-i-zer since I understand it simplistic approach and just have a hard time putting my faith in things like tapered ball seats and "special" WDH bar tapers to substitute for the more traditional "friction/brute force" methods. Obviously the high end "premium" systems (HA, Pull-Rite, Pro-Pride) are in a category of their own an not a consideration here. The only "quirks" with the Equal-i-zer is/was the "L" brackets (moving, retaining nuts loosening, excessive slop) and improvements addressing some of these minor issues have been incorporated since I got my system back in 2007.

Good luck with whatever you decide.

Larry

[Mike_Up]

Thanks John. I completely agree about what you're saying. The people I talked with at Blue Ox previously, swear that the new Sway Pro controls sway much better than the old with the friction control bolts. They are really proud of the system and proved that point to me, as I spoke to an engineer and the VP and there were several posts.

Unfortunately, my dealer wouldn't pony up for an entire new system and only replaced the obvious broken parts. Now that I'm seeing more damage that couldn't be seen until the system was pulled and dismantled a few times, I'm think I'm done with it. I just don't trust the Reese Dual Cam parts as there maybe other unforseen stresses that could cause failure.

Besides if it was all new, I wouldn't trust it not to bind up again. I wish I would had bought a new Equalizer or Blue Ox system with the new trailer. To many issues with the Dual Cam bars contacting the cam arm lobe brackets and mainly due to Reeses direction saying 5 links are needed which doesn't provide enough clearance.

Thanks again.

[Mike_Up]

OK I FINALLY SEE the affect as I was reading an old email from one of their engineers.

He stated this new head offers supperior sway control and now I see why. It finally just dawned on me and it's very simple but very effective.

First as mentioned, the spring bars bend much more than any other makers bars and Blue Ox took advantage of this.

They angled their head more than other heads because they can get away with it because the bars will bow, while other bars would be straighter interfereing with ground clearance and the such.

The steep angle, which is greater than the Reese trunnion, Equalizer brand and even Blue Oxs old head, allows the bar to swing up when pushed outward and load more, putting more push on that side, while the other bar swings inward and down, putting less force than normal, allowing the other side to push toward it, in that direction.

This force isn't done by other system because they don't have the steep head downward tilt that the Blue Ox head has, which is allowed by the bars ability to bend up and not have inteference issues.

The older head didn't have this steep downward tilt but relied on friction bolts in the head to control sway.

As the engineer pointed out to me, they wanted to do away with the friction bolts as they caused 'dog tracking' in his terminology.

I guess I didn't clearly understand it the first time I read it because I didn't realize it was the same tilt other makers use, but at a more extreme angle coupled with a spring bar that will bow to allow ground clearances.

The old head would also bend the bars BUT the head tilt angle wasn't as severe so the new system will likely have more chain links between the chain bracket and the bar. However with the new rotary latch, it's not as pronounced as the rotary latch limits the chain's motion, which in itself contributes to additional sway control.

I think I'll be purchasing this system. 🙂

[JBarca]

Mike Up wrote:
Very good explanation John.

What I don't really understand, as you have stated as well as Blue Ox, is how having the flex creates more spring force than a simple Reese Trunnion chain system without any sway control added.

Even though the Reese bars don't flex as much, they are still adding in force that's equal, as long as you use the same rated bars, chain links, and head tilt. I just can't see how the flex matters as long as there is force.

Hi Mike,

I agree, this is hard to see. I do not know how effective it is. The thing that is different is the angle of the trunnion pin. That large angle "may" help to guide the TT back towards center with the added WD bar force. If the pin was true vertical like many traditional WD hitches it would not have this same effect. I have read this effect before. See here you can create it on a standard round bar WD hitch.

Andy Thompson of Can Am RV in Canada wrote this: See full article: here

Andy wrote:
6) Next check the angle on the ball mount. The ball mount should angle back as much as possible. This angle on the ball mount acts like the forks of a bicycle - it makes the unit want to stay in a straight ahead position (that is why you can ride a bike with no hands).

While Andy does do some "different" things from time to time, I do respect him enough to listen even if I do not always agree. I have to think more on this castering effect to see if I can sort out more on how that angled pivot pin helps guide the TT back in line.

The down side is, the TT has to go this far out to create the effect.

I agree with your other statements, too much hitch head friction can aggravate dog tracking and not allow the camper to come back in align. The lighter the TT and stronger the head friction, the worse this gets.

Hope this helps

John

[BenK]

Guys, that is almost exactly what said last month about their flattened spring
bars

Here is how I see the similarities and how they differ

The traditional systems with 'cams' and/or the spring bar ends 'bent' both increase
the amount of spring bar tension as the trailer moves off center line

The other sway control or resistance is when those bars move up in tension there
is another resistance to moving off line and that is the force trying to ride up
on the cams or bent bar ends

The Ox works similarly, but the difference is in their chain hookup. There is
less number of links 'free' and most on the Ox are 'captured' within their
system

That then resists the bar from 'pushing' the chain bracket rearwards, whereas
in the traditional system with more 'free' links, the chain just sways or allows
the spring bar to move rearward

Since the spring bars are flattened horizontally, it will bend vertically easier
than sideways. Another sway control item, as the traditional spring bars/trunnions
will bend easier than these (an assumption, as do not know their metallurgy,
hardness, etc)

I like the dialed in cast head tilt. Less components to both corrode and adjust.
Also less to loosen, or fall off

Again, the more I noodle this system, the more I like it

[Mike_Up]

Very good explanation John.

What I don't really understand, as you have stated as well as Blue Ox, is how having the flex creates more spring force than a simple Reese Trunnion chain system without any sway control added.

Even though the Reese bars don't flex as much, they are still adding in force that's equal, as long as you use the same rated bars, chain links, and head tilt. I just can't see how the flex matters as long as there is force.

I do understand everything that you're stating, I just can't see how it's 'better' than a standard none sway control Reese Trunnion system.

It also looks like Blue Ox seems to feel that the Rotary latches take the place of the built in friction sway control in the head.

I did talk to many upper level employees at Blue Ox and they told me that they did away with the friction control in the head because it was causing "dog tracking". I also heard complains from Equalizer brand owners of the same problem with their built in head friction.

Blue Ox obviously replaced this head friction sway control with the rotary chain latches PLUS they can now claim 4 points of sway control like the Equalizer brand.