Interesting experiment

[Lex M]

This is interesting for European trailers:
http://towingstabilitystudies.co.uk/..._simulator.htm
and this too:
http://towingstabilitystudies.co.uk/...avansnake.html

How about NA-trailers?

[ronsmith100]

This is interesting for European trailers:
http://towingstabilitystudies.co.uk/..._simulator.htm
and this too:
http://towingstabilitystudies.co.uk/...avansnake.html

How about NA-trailers?

I have to admit that the Europeans seem to have (in my opinion) a more rational view of sway. Most American trailer RVers are so pro anti-sway bar that they make unnecessary attempts to belittle anyone who asks simple questions about it. Reminds me of the IPCC.

[John Perry]

I have to admit that the Europeans seem to have (in my opinion) a more rational view of sway. Most American trailer RVers are so pro anti-sway bar that they make unnecessary attempts to belittle anyone who asks simple questions about it. Reminds me of the IPCC.

Those of us that have been towing for years realize that if you NEED a sway bar there is something wrong with your rig!
A sway bar is a band aid to cover up a serious problem.
John

[KamperBob]

A properly balanced trailer can still exhibit minor sway in certain conditions. Sway control can be value added. Many folks with a great deal of towing experience understand this. The fiber egg world combined is but a fraction of the towing universe, and not everyone has the same comfort threshold where sway is concerned.

Cheers,
-KB

Those of us that have been towing for years realize that if you NEED a sway bar there is something wrong with your rig!
A sway bar is a band aid to cover up a serious problem.
John

[ronsmith100]

A properly balanced trailer can still exhibit minor sway in certain conditions. Sway control can be value added. Many folks with a great deal of towing experience understand this. The fiber egg world combined is but a fraction of the towing universe, and not everyone has the same comfort threshold where sway is concerned.

Cheers,
-KB

may I say that I don't think the little "wiggle in the fanny" you feel when a truck goes by you is the "sway" most people are talking about when addressing the need for an anti sway bar.. that's because there are two kinds of sway:

1) the immediately correcting and normal straightening of trailer after getting a little off-line as shown in the flash animation linked. This is what happens when the trailer is properly loaded.
2) Oscillating yaw sway. This type of sway cannot be easily corrected without an anti-sway bar because the inertia of the initiating "wiggle sway" can overwhelm the "immediately correcting and normal straightening of trailer after getting a little off-line". An incorrectly loaded trailer can kill you this way. An anti sway bar is very valuable here.

For #1 an anti-sway bar is of no value other than to cancel the fanny wiggle that is sometimes a good reminder to slow down.
For #2 a sway bar is an absolute must for safety.

I prefer never to miss-load to the point that #2 is necessary.

[Pete Dumbleton]

Umm, don't overlook the fact that once a friction sway bar slips, it takes equal force to bring the trailer back in line with the tow vehicle. That's why the Bandaids can be dangerous under slippery conditions or under an extreme yaw condition.

IMHO, the worse danger is that they can mask yaw sway and allow one to get going faster with worse results if something happens.

Anyone using a friction sway bar should know when to loosen or disconnect it and should also occasionally disconnect it for normal towing to see if it is masking a sway condition because one changed the loading.

The sway control incorporated in some WDHs is much better, IMHO.

[Pete Dumbleton]

How about NA-trailers?

Lex, check out this MFROG thread:

http://www.fiberglassrv.com/board/in...howtopic=27936

which contains a link to a YouTube video about a GM anti-sway system. Also, there are some other links on that site to so interesting RV stuf.

[Byron Kinnaman]

2) Oscillating yaw sway. This type of sway cannot be easily corrected without an anti-sway bar because the inertia of the initiating "wiggle sway" can overwhelm the "immediately correcting and normal straightening of trailer after getting a little off-line". An incorrectly loaded trailer can kill you this way. An anti sway bar is very valuable here.

For #2 a sway bar is an absolute must for safety.

I prefer never to miss-load to the point that #2 is necessary.

Looks like the operating words are "incorrectly loaded".

As I think of properly loaded trailers and anti-sway bars I can't help but wonder about the safety of using one vs not. With all the noise about anti-sway friction bars I've wondered if I needed to include one. The answer I came up is no.

Reasonings: An anti-sway bar simply creates a stiffer side to side connection between the TV and the trailer. The good points is that it's more difficult to put the trailer out of alignment when going in a straight line. The bad points it's more difficult to go around a corner. The tires instead of traveling behind want skid sideway, thus side loading the tire side walls. This probably is much problem other than increased tread wear when on dry pavement. However when it's wet or any other condition with less than ideal traction the tires could break loose. Now instead of providing a nice safe condition, the trailer is now a big weight on the end of a pendulum, which wants to take the rear of TV on ride side ways. That's probably not a good thing.

Here in the NW there's probably as much of the time with damp or wet roads as without. So if you follow instructions and remove the anti-sway bar in those conditions 50% or more of the time it's not attached. We also get on gravel roads from time to time. Gravel can be as bad as rain or snow even. The situations that can cause sway don't take a break when traction is less than ideal.

Therefore the best thing is to make sure you're trailer is always properly load balanced for towing and don't bother with the anti-sway bar.

JMHO.

[Dan B]

Looks like the operating words are "incorrectly loaded".

As I think of properly loaded trailers and anti-sway bars I can't help but wonder about the safety of using one vs not. With all the noise about anti-sway friction bars I've wondered if I needed to include one. The answer I came up is no.

Reasonings: An anti-sway bar simply creates a stiffer side to side connection between the TV and the trailer. The good points is that it's more difficult to put the trailer out of alignment when going in a straight line. The bad points it's more difficult to go around a corner. The tires instead of traveling behind want skid sideway, thus side loading the tire side walls. This probably is much problem other than increased tread wear when on dry pavement. However when it's wet or any other condition with less than ideal traction the tires could break loose. Now instead of providing a nice safe condition, the trailer is now a big weight on the end of a pendulum, which wants to take the rear of TV on ride side ways. That's probably not a good thing.

Here in the NW there's probably as much of the time with damp or wet roads as without. So if you follow instructions and remove the anti-sway bar in those conditions 50% or more of the time it's not attached. We also get on gravel roads from time to time. Gravel can be as bad as rain or snow even. The situations that can cause sway don't take a break when traction is less than ideal.

Therefore the best thing is to make sure you're trailer is always properly load balanced for towing and don't bother with the anti-sway bar.

JMHO.

Just wonderring has anyone actually dne a weight check on their trailers to see if the weight is equal from side to side? It seems to me that with the fridge and stove on the passenger side of my scamp that tire always appears to be low when it is not. Do the manufacturers make an effort to balance from side to side?

[Roger H]

Dan, many folks have done individual wheel weights, and the "appliance" side is almost universally two hundred or so pounds heavier than the non-appliance side, particularly in Scamp 16s where the entire galley is typically on one side of the trailer. That varies, of course, from trailer to trailer. The up side is that the closet can be filled with clothing items or whatever to make up some of the imbalance.

The larger the trailer, the more opportunity there is to balance the weight by the placement of tanks, bath, refrigerator on one side, stove, sink, and oven on the other, etc. etc. etc.

Roger

[Pete Dumbleton]

I've done side-to-side checks and they were OK. I presume that was because my white-water tank is on opposite side from kitchen and battery is in the middle.

It was easy to check all kinds of weight combinations when WA left the weight stations on when not in use and you could read the scale from outside.

My truck, however, was not equal because the 30 gallon fuel tank AND the driver were on one side...

[ronsmith100]

I've done side-to-side checks and they were OK. I presume that was because my white-water tank is on opposite side from kitchen and battery is in the middle.

It was easy to check all kinds of weight combinations when WA left the weight stations on when not in use and you could read the scale from outside.

My truck, however, was not equal because the 30 gallon fuel tank AND the driver were on one side...

I'm afraid to weigh each wheel now.
Not only is my galley on the right side so is the 20 gallon water tank and so is the the storage closet and so is the second battery and so is the microwave and so is my TV and so is.....





I am now afraid

I guess I could leave the black water tank full to compensate




ARGHHHHHHHHHHHHHHHH

[Pete Dumbleton]

I'm afraid to weigh each wheel now.

I am now afraid

I guess I could leave the black water tank full to compensate

Don't be afraid -- Do a paper exercise to estimate the front-back and side-side weight distributions and then run the simulator to see various effects. It should give you an indication as to whether you are in trouble or not and will demonstrate safe vs unsafe speeds.

[Mike Watters]

That's a lot of fun!

I wasn't able to get either link to run at work but both are aces at home.

The main thing I appreciate is how it separates out what they called yaw inertia from the simple relative hitch weight which is all I recall people talking about much. The second site I found very informative personally.


Mike

[Frederick L. Simson]

Warning:

The following is a test of the Emotional Outburst System.

This is only a test.

ARGHHHHHHHHHHHHHHHH

This concludes the test of the Emotional Outburst System.

Had this been an actual emotional outburst, you would have been provided with information on where to find copious amounts of chocolate.

Thank you.

I now return you to your regularly scheduled rant.

[Pete Dumbleton]

That's a lot of fun!

I wasn't able to get either link to run at work but both are aces at home.

The main thing I appreciate is how it separates out what they called yaw inertia from the simple relative hitch weight which is all I recall people talking about much. The second site I found very informative personally.


Mike

Remember the basics -- Get some weight on the tongue and pack all your heavy stuf as close to the axle as possible (both in horizontal and vertical distance).

One thing the simulator model didn't address directly is packing stuf high, like in upper cabinets or on roof -- What happens there is that in the first sway, the weight transfers in part to one wheel and then to the other as the sway goes in the opposite direction, so it's essentially affecting the side-to-side weight distribution.

[james kent]

I have never towed a trailer that had sway bars attached so I can't address that. BUT. A driver who constantly see-saws back and forth on his steering wheel will automatically add sway into his package. While a driver who makes small corrections and does it smoothly adds very little or no sway. Our 13 footer sticks like it's been glued into place. We used to tow a 20 ft boat and it's trailer with no sway problems. Now I can see where you might need bars if your towing something larger as a minor adjustment of the wheel in the tow is multipled by the length of the trailer. OTOH it's sometimes kinda nice to introduce a little sway into the scheme of things when there's a car stuck to your back bumper so close you can't see him in your mirrors and with a bit of sway you not only get a glimps of him, you can back him off a bit.
Jim

[Glen G]

One thing to remember is the simulator is for a Euro Trailer !

The Tow Vehicles are not designed to carry 10% to 15% tongue weight, so the trailer is designed with the axle in the middle of the trailer and the load must be near the middle or it will sway.

Another factor is speed most Euro towing is done at speeds below 50 m.p.h. The Euro trailer will become unstable at speeds above 62 m.p.h.


Here in the states the axle is biased to the rear making an automatic 10% to 15% tongue weight and thus a less likely chance of sway even if loaded slightly wrong.

The chance of sway greatly increases when the load moves to far to the rear thus reducing the tongue weight below 10%.

Towing speeds here are much higher 55-75 m.p.h. Most trailers here with 15% tongue weight are inherently stable to speeds of 100 m.p.h.

The limiting factor is the 65 m.p.h. speed rating of Trailer Tires.

[Lex M]

Another factor is speed most Euro towing is done at speeds below 50 m.p.h. The Euro trailer will become unstable at speeds above 62 m.p.h.

On European motorways most rigs speed between 90 and 100 km/h (56 - 62 m.p.h.) despite the speed limit of 80 km (50 m.p.h.) in many countries. The limit in France is 130 km/h (80 m.p.h.), in Belgium 120 km/h (75 m.p.h.), in the Netherlands the limit will be increased to 90 km/u (56 m.p.h.), in Germany 80 km/h (50 m.p.h.), with permit 100 km/u (62 m.p.h.). In practice in Germany police likes rigs to speed at the speed of lorries, which is in practice 90 km/h (56 m.p.h.).
On non-motorways the max speed is the same as for single cars (in most cases 80 km/u (50 m.p.h.))
Every rig has its critical maximum speed above which the rigs will be unstable. That speed depends on the trailer, the tow vehicle, the load and the distribution of the load.
Most tow cars allow tongue weights from 50 to 75 kg (110 - 165 lb).

[ronsmith100]

I have never towed a trailer that had sway bars attached so I can't address that. BUT. A driver who constantly see-saws back and forth on his steering wheel will automatically add sway into his package. While a driver who makes small corrections and does it smoothly adds very little or no sway. Our 13 footer sticks like it's been glued into place. We used to tow a 20 ft boat and it's trailer with no sway problems. Now I can see where you might need bars if your towing something larger as a minor adjustment of the wheel in the tow is multipled by the length of the trailer. OTOH it's sometimes kinda nice to introduce a little sway into the scheme of things when there's a car stuck to your back bumper so close you can't see him in your mirrors and with a bit of sway you not only get a glimps of him, you can back him off a bit.
Jim

I am beginning to think pulling trailers is like driving Cadillacs.

Remember in the old days we had those huge boats that rode so smooth? People would be sitting around talking about how they could drive all day long at 90 mph and, "never even feel the road". That was what sold large cars. It was Detroit's charter to build cars that isolated the driver from that road. I

However in Europe they built cars that brought you intimately in contact with the road. Even the largest Mercedes didn't try to isolate the driver from the road. Their steering was quicker and their suspension far more firm than American cars.

Well if you remember those days like I do then maybe you can see why some people want sway bars when they don't need them. I have a sway bar and I don't need it but if I wanted to drive at higher speeds and isolate the natural trailing wiggle from my truck I could put it on and go Cadillacing down the road. People drive MUCH faster with sway bars because their purpose is to never feel like they are pulling a trailer and so the trailer never gives them tactile feedback... and this is very dangerous thinking IMO.