Trailer Sway

[dalamarjj78]

Originally Posted by travelin texans

While contemplating the truck trade consider that due to minimal payload increase from a 1/2 to a 3/4 ton + the minimal difference in price, ride & mpg skip the 3/4 ton & go with a 1 ton SRW, you'll have a considerable payload increase so you're prepared for the next rv upgrade, I think in the long run you'd be glad you did.

This is a very good point and earned an, "I told you so" from my wife. It's definitely something we'll keep in mind shopping for a new TV. We don't plan on upgrading the trailer for a while but if we do ever decide to go to a 5th wheel it would be nice not having to worry about getting a new TV, too.

Originally Posted by 08quadram

I have the 1,200-12,000k bars on mine. My trailer has a GVW of 7,600 lbs. It was a carry over from my passport which was 7,500lbs gross.

Good to know the 1,200/12,000 option works for yours since mine is the same weight. Thanks!

[bbells]

I had a cheaper eaze lift wdh with 2 added anti sway bars. I almost gave up pulling a trailer. The equalizer 4 point i just put on made all the difference in the world. I barely feel the wind or the semis driving by. No more white knuckling or needing to keep under the speed limit. If you want to tow a trailer the cheap wdh's are a big mistake, IMHO.

[pdaniel]

I was also going to recommend the “Equalizer” brand. They don’t look as pretty as others but they do a great job-towed TTs from 26 to 36 with one for 20 years. I would also recommend airbags (I won’t get into discussions about truck sizes or capacities).

[bbells]

Originally Posted by pdaniel

I was also going to recommend the “Equalizer” brand. They don’t look as pretty as others but they do a great job-towed TTs from 26 to 36 with one for 20 years. I would also recommend airbags (I won’t get into discussions about truck sizes or capacities).

I agree. Air bags are a cheap, easy enhancement that help towing.

[Mikelff]

One last thing to always check is equal tire pressure on Truck and trailer. Unequal tire pressure can add to sway issues.

[dalamarjj78]

Originally Posted by bbells

I had a cheaper eaze lift wdh with 2 added anti sway bars. I almost gave up pulling a trailer. The equalizer 4 point i just put on made all the difference in the world. I barely feel the wind or the semis driving by. No more white knuckling or needing to keep under the speed limit. If you want to tow a trailer the cheap wdh's are a big mistake, IMHO.

I really hope the upgrade in hitch gives us the same results. The Recurve we have was one that a previous dealer threw in on our first trailer purchase and I have been less than impressed with it, for sure.

Originally Posted by Mikelff

One last thing to always check is equal tire pressure on Truck and trailer. Unequal tire pressure can add to sway issues.

Thanks. I always make it a point to check/refill the tires of the trailer and truck before every trip (65psi on the trailer, 44psi on the truck).

[slow]

Originally Posted by dalamarjj78

I really hope the upgrade in hitch gives us the same results. The Recurve we have was one that a previous dealer threw in on our first trailer purchase and I have been less than impressed with it, for sure.



Thanks. I always make it a point to check/refill the tires of the trailer and truck before every trip (65psi on the trailer, 44psi on the truck).

If keeping the truck, consider upgrading to LT tires. P rated are not the best for towing a heavy load.

[ehidle]

If your trailer sways at all, the center of gravity of your trailer is too far aft and needs to be moved forward.

[flybouy]

Originally Posted by ehidle

If your trailer sways at all, the center of gravity of your trailer is too far aft and needs to be moved forward.

Not necessarily, excessive tongue weight Wil lift the tow vehicle steer axle creating sway and a trailer with a large sail area will cause sway if the TV is too light or the wheelbase is too short even if the trailer is correctly balanced.

[ehidle]

Originally Posted by flybouy

Not necessarily, excessive tongue weight Wil lift the tow vehicle steer axle creating sway and a trailer with a large sail area will cause sway if the TV is too light or the wheelbase is too short even if the trailer is correctly balanced.

Well technically that's instability in the tow vehicle caused by insufficient tracking authority, not sway in the trailer. But yes it is also a large problem that is to be avoided.

[flybouy]

Originally Posted by ehidle

Well technically that's instability in the tow vehicle caused by insufficient tracking authority, not sway in the trailer. But yes it is also a large problem that is to be avoided.

Where did you read that? What you are describing (instability in the tow vehicle caused by insufficient tracking authority) can have many causations like worn ball joints, worn tie rod ends, other worn or improperly adjusted steering and suspension components, improperly inflated tires etc.

To say wind forces don't induce sway is just incorrect. Otherwise, I guess a trailer flipping on it's side from wind is Technically" the tow vehicle insufficiently keeping it from falling over?

[ehidle]

Originally Posted by flybouy

Where did you read that? What you are describing (instability in the tow vehicle caused by insufficient tracking authority) can have many causations like worn ball joints, worn tie rod ends, other worn or improperly adjusted steering and suspension components, improperly inflated tires etc.

To say wind forces don't induce sway is just incorrect. Otherwise, I guess a trailer flipping on it's side from wind is Technically" the tow vehicle insufficiently keeping it from falling over?

I didn't really mean to say that wind would not induce sway. But, wind will not induce trailer sway in a towing configuration that is balanced properly. The prevailing computer models use a 4th order system to describe the towing dynamics in a two-vehicle system. The solution to the differential equations for that system have two sets of eigenvalues, one for the tow vehicle and one for the towed vehicle (which is to say that there can indeed be oscillation in either vehicle). Wind certainly can induce sway in an already unstable or conditionally stable system where some energy needs to come from somewhere to start an oscillation.

Also I don't really define the wind pushing your trailer back and forth as sway. Sway (at least to me) has a specific definition, and that is the condition where the trailer equation has a solution with positive feedback (the exponential part of the solution for the trailer has a positive tau, or a negative damping factor) where once the system starts to oscillate, the oscillations get bigger without further input.

Instability in the tow vehicle can certainly come from having too much tongue weight. If you look at the forces, a lateral movement of the trailer at the hitch ball (for example caused by wind) puts force in one direction on the hitch ball, which puts an opposing force on the front wheels of the tow vehicle (the rear axle makes a 2-dimensional pivot for the lever). Hitch weight also takes weight off the front wheels, which does two bad things. One of those bad things is that it reduces the effective caster angle (remember caster is what makes the wheel want to track in a straight line), making the wheels more prone to wobble like a Walmart shopping cart. The other bad things is just reducing weight on the steering wheels, which if you do enough will cause the whole darn thing to lurch around on you every time you go into a curve, which if you have ever felt it, you will know that it can get away from you in a hurry.

Anyway, if you're into the math, this is one of the more concise papers I've seen on it:

https://pdfs.semanticscholar.org/4e8...336eef1e34.pdf

[flybouy]

Originally Posted by ehidle

I didn't really mean to say that wind would not induce sway. But, wind will not induce trailer sway in a towing configuration that is balanced properly. The prevailing computer models use a 4th order system to describe the towing dynamics in a two-vehicle system. The solution to the differential equations for that system have two sets of eigenvalues, one for the tow vehicle and one for the towed vehicle (which is to say that there can indeed be oscillation in either vehicle). Wind certainly can induce sway in an already unstable or conditionally stable system where some energy needs to come from somewhere to start an oscillation.

Also I don't really define the wind pushing your trailer back and forth as sway. Sway (at least to me) has a specific definition, and that is the condition where the trailer equation has a solution with positive feedback (the exponential part of the solution for the trailer has a positive tau, or a negative damping factor) where once the system starts to oscillate, the oscillations get bigger without further input.

Instability in the tow vehicle can certainly come from having too much tongue weight. If you look at the forces, a lateral movement of the trailer at the hitch ball (for example caused by wind) puts force in one direction on the hitch ball, which puts an opposing force on the front wheels of the tow vehicle (the rear axle makes a 2-dimensional pivot for the lever). Hitch weight also takes weight off the front wheels, which does two bad things. One of those bad things is that it reduces the effective caster angle (remember caster is what makes the wheel want to track in a straight line), making the wheels more prone to wobble like a Walmart shopping cart. The other bad things is just reducing weight on the steering wheels, which if you do enough will cause the whole darn thing to lurch around on you every time you go into a curve, which if you have ever felt it, you will know that it can get away from you in a hurry.

Anyway, if you're into the math, this is one of the more concise papers I've seen on it:

https://pdfs.semanticscholar.org/4e8...336eef1e34.pdf

Well now that's all real interesting at an engineering convention. When I was an adjunct faculty member in a nearby college I recall the best advice I ever received and that was to know your audience .

So here's the point, I don't want someone new to towing to get the idea that the "only" way to have a trailer sway is the condition of insufficient tongue weight because the average reader only knows the term "sway" to describe what they are experiencing.

[foldbak]

My 2 cents!

https://andersenhitches.com/Catalog/...e-wd-kits.aspx


And a 2500 wouldn't hurt It was tough for me to accept but after biting the bullet it was the best thing I ever did!

[travelin texans]

Originally Posted by ehidle

I didn't really mean to say that wind would not induce sway. But, wind will not induce trailer sway in a towing configuration that is balanced properly. The prevailing computer models use a 4th order system to describe the towing dynamics in a two-vehicle system. The solution to the differential equations for that system have two sets of eigenvalues, one for the tow vehicle and one for the towed vehicle (which is to say that there can indeed be oscillation in either vehicle). Wind certainly can induce sway in an already unstable or conditionally stable system where some energy needs to come from somewhere to start an oscillation.

Also I don't really define the wind pushing your trailer back and forth as sway. Sway (at least to me) has a specific definition, and that is the condition where the trailer equation has a solution with positive feedback (the exponential part of the solution for the trailer has a positive tau, or a negative damping factor) where once the system starts to oscillate, the oscillations get bigger without further input.

Instability in the tow vehicle can certainly come from having too much tongue weight. If you look at the forces, a lateral movement of the trailer at the hitch ball (for example caused by wind) puts force in one direction on the hitch ball, which puts an opposing force on the front wheels of the tow vehicle (the rear axle makes a 2-dimensional pivot for the lever). Hitch weight also takes weight off the front wheels, which does two bad things. One of those bad things is that it reduces the effective caster angle (remember caster is what makes the wheel want to track in a straight line), making the wheels more prone to wobble like a Walmart shopping cart. The other bad things is just reducing weight on the steering wheels, which if you do enough will cause the whole darn thing to lurch around on you every time you go into a curve, which if you have ever felt it, you will know that it can get away from you in a hurry.

Anyway, if you're into the math, this is one of the more concise papers I've seen on it:

https://pdfs.semanticscholar.org/4e8...336eef1e34.pdf

Just a dumba## country boy & didn't understand a word of this????
But for newbies reading;
Wind will induce sway!
Buy the best WDH with sway control you can afford!
Too much truck is MUCH better than just enough!
Don't let anyone tell you that thier 5/8 ton truck is enough (I'll spill the beans, there's no 5/8 ton truck)!