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Old 11-27-2016, 08:17 AM   #21
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Quote:
Originally Posted by Raspy View Post
Paul,

Are you sure the trailer brakes are operated separately on any sway controllers?
When a trailer brake is applied to one side only, the rear of the TV is pulled to that side, which points the TV slightly in the opposite direction. A right side trailer brake applied steers the TV to the left.

Seems to me that would cause instability. When a trailer begins to sway you can manually apply the trailer brakes together at the controller and straighten it out. I have a trailer with a brake that holds harder on one side and it definitely steers my truck.

Some have even commented that anti-sway hitches can conflict with the stability systems in modern trucks. Anderson Hitch recently responded to a comment about this by recommending the stability system in the truck be turned of if they conflict, to which I seriously questioned them.
I am pretty sure that at least some of them apply the trailer brakes individually (left-right). It is the same idea as in the car/truck stability systems.
Only after they are used a lot, in real-life situations, will we know which work best. You are correct in your analysis. If the response time of the active control system is too slow, or it gets out of phase, it could make things worse! (You mentioned the reported conflict between some of them.) The passive sway control systems are simple and they respond instantly, except when the mechanical links develop play. These have been time tested, so if I had to deal with sway problems, I would start with the passive sway control and wait for feedback (no pun intended) from users of the active systems, knowing that all of them will be some sort of a trade-off.
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Old 11-27-2016, 09:56 AM   #22
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If any system applies brakes selectively that would mean that there is an electrical connection to each brake meaning two brake connections in the plug.
This is not there for any of the quick connect systems that plug into a converter or the car.
There are systems that do split the brakes, but the Hayes is not one since it uses the same plug that plugs into car socket.
The Tuson Sway Control does actuate each brake separately



The AL-KO Europe has a similar system that works with the mechanical surge brake systems in use there.
There may well be some benefit to differential braking especially if it was electronically activated by the Tow Vehicle's electronic sway control.

The Direct-link system that links into the car's CanBus system and this could be an advancement for those vehicles supported.
There are systems in Europe that tie the ABS systems into the trailer brakes as well, but I don't have any further information on those.
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Old 11-27-2016, 10:32 AM   #23
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Tennessee
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The trailer tow ESP in practice doesn't use trailer brakes but rather takes into consideration the trailer when applying tow vehicle brakes. The weight, size and distribution of the trailer has to be considered when computing correct brake application of the trailer - something the tow vehicle has no knowledge of. But tow vehicle can measure acceleration in three dimensions (yaw, roll, pitch) and anticipate push from trailer when an event occurs.

Just like ABS and airbags are no excuse to drive dangerously, trailer ESP is not to fix poor loading or setup of a trailer.

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Old 11-27-2016, 12:56 PM   #24
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Thanks everyone, a lot of good information here.
Over the past 40 plus years I have towed a number of configurations under all sorts of conditions. I have also spent the past 35 years as a Health and Safety professional. My focus as such is to identify hazard potentials and address them to avoid incidents. Hazard elimination is always the most effective approach. Hazards that can't be eliminated must be controlled to the extent reasonable and practicable to reduce incident potential to acceptable levels.
When hazards aren't effectively identified and addressed, incidents result. My role then becomes investigating the incident to determine what went wrong and how to improve the situation to prevent recurrence. The worst incidents involve fatalities. The worst fatalities involve children.
Sway indicates an unacceptable hazard as the tow vehicle trailer combination is now an unstable unit and unsafe to tow, both for the people in this unit and others on the road.
Anti sway mechanisms can improve things marginally however they often require a level of knowledge and understanding that may not be common to some, especially those with limited towing experience. Also, any strategy of marginal effectiveness under normal conditions will likely be entirely inadequate under more extreme conditions.
If sway is a problem, it's best to determine what is causing it and address that issue. Using anti sway mechanisms doesn't really solve the problem in most recreational unit situations or provide the level of safety we really want. Your focus is the safety of yourself and your family. The focus of those who sell these devices may not be the same.
Trailering should be a pleasant experience. If it isn't safe, it's not likely to be pleasant. If it isn't a pleasant experience, why would we do it?
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Old 11-27-2016, 07:41 PM   #25
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Quote:
Originally Posted by Mike_L View Post

If sway is a problem, it's best to determine what is causing it and address that issue. Using anti sway mechanisms doesn't really solve the problem in most recreational unit situations or provide the level of safety we really want. Your focus is the safety of yourself and your family. The focus of those who sell these devices may not be the same.
Trailering should be a pleasant experience. If it isn't safe, it's not likely to be pleasant. If it isn't a pleasant experience, why would we do it?
Of course all of this is true, and I'm sure we all realize it, but it misses the point in many cases. I, for one would never continue to use a trailer that was unstable, once I figured out it was. Who would?

The problem happens all of a sudden and you have to do what you can to get it under control, if possible, or crash it. For instance: my father crashed his new travel trailer on the way home from picking it up. All of a sudden it was whipping and he rolled his TV. I had one where everything was just fine until I got to 60 MPH and then it took me all over a six lane freeway trying to get it back under control. Everybody behind me, across the entire highway backed way off to get out of harms way.

Point is: probably no one realizes they have a problem until that problem shows up and gets out of control. So, preventive measures are prudent. Those measures are mass centralization in the trailer with no rearward weight bias, such as could be caused by those carrying platforms plugged into a receiver behind the trailer. Some tongue weight is a must. Weight kept low in the trailer. Tires aired up properly in the TV and trailer. Driving at reasonable speeds. Extra caution in crosswinds and when being passed by semis. Trailer sitting level while towing. Trailer not overloaded and TV not overloaded. A tow vehicle with a wider, lower stance, such as a full sized pickup vs a Rav 4 or older jeep Cherokee. A tow vehicle that is significantly heavier that the trailer, or at least well within it's factory spec towing limit.

EVERY trailer should absolutely, without exception, have brakes. I like my trailer brakes setup such that they are a bit more aggressive than the truck brakes. Feeling the trailer pull back slightly every time I brake reminds me they are working and gives a bit of comfort. I never want the trailer pushing the truck, and pulling back cures fishtailing.

Some swaying is normal and not a problem with winds and dips and such, but the instability of a fishtail that gets worse and worse quickly, on it's own, is very scary. There is a difference between "unstable" and responding to road conditions or wind.

Some say an anti-sway device simply masks the problem. Maybe, but if you don't know you have a problem and want a bit of insurance, fine. Use one for peace of mind even though you might never have a problem without it. No harm done. During the life of the trailer with all the miles and trips it goes on, there is bound to be many different loads carried in many different forward/rear weight biases.

The first couple of trips with my new Ollie were all about learning it's character and looking for instability. It came with an Anderson hitch that I have never used and don't want to use. No problem with stability and now I'm more relaxed. The Anderson hitch stays home.
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Old 11-27-2016, 08:00 PM   #26
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I tow my 17' Escape with a RAV4 V6 Sport with a Pro Series weight distribution hitch and no "sway control". I don't experience sway, passing or being passed by semis, in winds or the couple times I've had to aggressively avoid an obstacle.
I keep heavy items down low and over the axle as much as possible. I use a Sherline tongue scale and generally weigh in at 320 lbs.
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Old 11-27-2016, 08:49 PM   #27
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All good points. If everyone was this conscientious about towing we would likely have many fewer incidents and more happy trips.
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Old 11-27-2016, 10:21 PM   #28
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I'm a fan of more weight on the tongue of the the camper with the rear suspension of the TV compatible.
My TV (2002 Taco) has an extra leaf added to support the added weight of the 2 6V batteries and a propane tank on the tongue of my 4500.
No sway, ever.
As an interesting test (I've never weighed tongue vs. GVW on my camper). In So Cal this spring, my girlfriend and I wanted to move/pivot our camper into a camp spot (such that our door faced the fire pit, not the neighbor's giant RV). We tried to manually cary the tongue together; possible, but a real struggle. Had her sit on the spare tire off of the rear bumper; boom!, way easier, set a 5G water jug up
there with her and it was easy to maneuver by hand (on flat ground).
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Old 11-27-2016, 10:50 PM   #29
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I recently met a very nice couple from Germany that come over here at least twice a year and travel all over with their Airstream towed by a BMW SUV. They leave their rig parked here between trips.

He had a conventional load leveling hitch on the BMW to carry the heavy Airstream. We got to talking about that and he said they don't use leveling hitches in Germany as trailers are set up to near neutral tongue weight and none is needed.

Makes sense to me. There are more factors than just tongue weight. Is the weight over the axles and not at the ends? How far back do the axles sit from the ball? There is a lot going on with trailer geometry and weight distribution.

I also find the more weight on the ball of the TV, the more jarring the ride. My toy hauler had it's water tank right in the front of the trailer, plus the batteries were on the tongue, and it made my Ram ride rough. I tried it with and without a load leveling hitch and was never very happy. My Ollie has everything centered front to back much better and the batteries are right over the axle. I keep forgetting it's back there with a tongue weight of about 450 lbs.
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Old 11-28-2016, 07:58 PM   #30
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Here is something that just showed up on another thread:http://www.fiberglassrv.com/forums/f...tml#post618227
The ProPride/Hensley hitch is touted here as a means to make the life of a trailer thief more difficult, but it is otherwise quite relevant to this discussion. It seems to be a very effective, passive sway control device. At some (significant) expense in money and more weight on the tongue it shifts the pivot point forward, to the location where the 5th wheel trailers connect, near the rear axle. It might be even better, since the projected pivot point (3P) is lower to the ground.

However, the $2.5k ProPride cost is almost as much as the price difference between a 16' Scamp and its 19' 5th wheel sibling.
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Old 11-28-2016, 10:59 PM   #31
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Paul,

Thanks for that. I've never seen those hitches. I would hate to have to buy and use one of those just to keep my trailer from crashing.
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Old 11-29-2016, 04:36 AM   #32
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We are extremely glad we bought the ProPride. No matter what we did loading and even with a weight distribution hitch, our Bigfoot Silver Cloud was subject to heart-stopping sway. My husband no longer has to watch constantly for oncoming traffic and grip the steering wheel with both hands when semis and especially busses pass us. On our last trip, I pointed out a bus passing us while he had one hand on the steering wheel. He had not even noticed (and he does not speed).

Admittedly, my family had sold my father's farm, so I had the funds to pay for this hitch. It is a huge relief to us, and a major theft deterrent. In fact, previously, I could not, with my hand disability and the need to be able to firmly grip the steering wheel, spell his driving at all, as I could with our previous Uhaul VT. Now, maybe I can help him get a break driving.

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Old 11-29-2016, 07:05 AM   #33
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Hi Cindy, in your case, you did absolutely the right thing buying the ProPride. It is about pointing out options and possibilities for people facing the sway problems.

I did not realize how big the Silver Cloud is. When the trailer is big and heavy enough, moving your loose stuff around the inside will have much less effect than doing the same in a small, light weight Scamp.
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Old 11-29-2016, 07:34 AM   #34
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Yes, I know the ProPride would not work on the smaller trailers. It is a monster in size. I think ProPride does most of their business with Airstreams. When we brought the Silver Cloud home from OR and the first semi hit us, even with a brand-new weight distribution hitch, it blew us all over the road. Scared us to death! We had to research how to combat the wind of the semis with that configuration and are now glad that it is no longer a concern with the new hitch.

And whoever commented that it needs electric brakes, that is correct.

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Old 11-30-2016, 08:02 PM   #35
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For those still interested in the ProPride hitch, here is one of their videos:

Quite informative.
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Old 11-30-2016, 08:30 PM   #36
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Hubby has not had good luck with the hitch mirror. We also discovered that while it says you can back up into the hitch from an angle, that is not a good idea. We had to when a truck was parked in our way, and the hitch just would not straighten out after we hooked it up.

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Old 12-02-2016, 10:28 AM   #37
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Trailer dynamics are complicated

Physics isn't the easiest discipline, but the good news is that there are exact answers available if you're willing to do the math or find somebody who has done the math for you.

Put simply, there are three controlling factors for the stability of a trailer and tow vehicle combination: Proportion of trailer weight on the hitch ball, ratio of trailer weight to tow vehicle weight, and polar moment of inertia of the trailer (proportion of the weight of the trailer at the ends versus over the axle).

The old rule of 10% of trailer weight on the hitch is not a bad one to work with. Yes, some combinations can get away with less, particularly with a short trailer (less polar moment), and a relatively heavy tow vehicle.

You can get away with a lot if the trailer is light relative to the TV and has a low polar moment. Here's a video that shows just how bad the trailer balance can be and still not result in disaster:



Note that the trailer is obviously extremely unstable, probably due to insufficient tongue weight. If the TV had been lighter, or the trailer longer, the outcome would not have been so happy, as with this example:



That F250 Powerstroke met its match there - the combination of too much weight on the rear cargo rack (note the two unsecured, probably full 20# propane bottles), a long trailer, and high speed had a predictable outcome. I would have locked up the trailer brakes immediately when I felt things moving around like that. I'm guessing that the driver either did not have a trailer brake controller installed or was inexperienced.

Here's a good example of a more 'European' towing model with a light TV and a heavy trailer. The large polar moment of the trailer in combination with low tongue weight and a light TV means that when the tail starts to wag the dog, even at low speed, the outcome will not be pleasant:



Note that the trailer is obviously as heavy or heavier than the TV. This guarantees that when the trailer starts oscillating, it's going to drag the rear axle of the car around with it, and there's not much the driver can do to prevent it.

Another less traumatic example:



Here's my favorite trailer dynamics video:



In my case, the trailer has about 9% tongue weight under normal circumstances. I would like that number larger, but it's hard to manage without moving more heavy fixed things around in the trailer. I'm careful to load heavy things forward of the axle, but there's only so much I can do. My trailer weighs 2200 lbs, and my TV is 4400 lbs, so I can afford to be a little cavalier with weight and balance.

That said, I don't put up with a little 'harmless' sway. If I notice any trailer sway at all, I pull over and move something around to stabilize the combination. I can't predict when I'm going to have a trailer tire blow out or some other destabilizing event.

The Europeans (and Australians, to a lesser extent) get away with lighter TVs with heavier longer trailers because their regulations require all the heavy stuff in the trailer very close to the axle. You'll note a lot of center kitchen layouts in these trailers, and this is specifically to manage the polar moment component of the problem. It's not a magic solution, though. European caravan combinations are normally restricted to much lower towing speeds than are common in the US in recognition of the lower stability that tongue weight below 10% causes.
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Old 12-02-2016, 12:48 PM   #38
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From what I've read there's some speed that all trailers will go into uncontrolled sway. The trick therefore is to the trailer balanced (weight low, over the axle, proper tongue weight, the right tires, the right tire pressure, etc.) so that the seed at which uncontrolled sway will occur is much higher than the maximum speed you're towing. Trailer tires typically have a maximum speed of 65 mph. LT and Passenger tires would be lower no matter what the side wall says. Therefore it seems to me that it's always best to keep the maximum towing speed close to 60 mph to give a slight margin of safety.
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Old 12-02-2016, 06:45 PM   #39
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I would like to see somebody knowledgeable about tires tell us about the maximum speed rating. I suspect that it has little to do with the critical speed of the tow vehicle with trailer system, and more to do with the construction, heat generation and resulting potential for overheating. But even so, the 65mph max. towing speed is still a good rule of thumb.
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Old 12-02-2016, 06:55 PM   #40
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Trailer: Scamp 16 Modified (BIGLY)
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I believe that the tire rating are just that limits for the tires.
Trailer tires are constructed for heavy loads and twisting turns when tandem axles are used.
The construction cords and rubber tend to run hotter especially with heavy loads.
65 mpg speeds are a good idea really without the limitation of ST tires.
It really is the physics involved that indicate the wisdom of controlled speeds.

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