So I guess a 1/2-ton truck is enough

[out of sight]

Originally Posted by KevinFH

Wrong. Just Wrong. It's as simple as this: with a 1/2 ton you may need to beef up suspension, but a properly configured 1/2 ton can easily pull 9000lbs. Which trailer is 9000?

On the other hand, and more capable truck can do it with spare payload. Don't be fooled that a 3/4 ton will solve all your 1/2 ton problems. Many F-250 owners are struggling with sway. We don't struggle. Our 1/2 half ton F-150 deisel rated for 10400lbs tow pulls our 28' FC no problem, but we had to add Roadmaster suspension to stop porpoising. Springs a little soft with 1000lb tongue.

The main thing that affects the stability of the rig is the relative weight (more accurately, the yaw inertia) of the tow vehicle to the trailer. If the tow vehicle is too light it can't resist the sway and lateral movement of a heavier trailer. There's no way to get around that fact. A half ton weighs in at 5k lbs compared to 8k for a 3/4 ton. You can't make up for the 3k difference with springs or hitches.

[BayouBiker]

Originally Posted by out of sight

The main thing that affects the stability of the rig is the relative weight (more accurately, the yaw inertia) of the tow vehicle to the trailer. If the tow vehicle is too light it can't resist the sway and lateral movement of a heavier trailer. There's no way to get around that fact. A half ton weighs in at 5k lbs compared to 8k for a 3/4 ton. You can't make up for the 3k difference with springs or hitches.

Here let me fix this for you....

Many factors affect stability of a towing system. The main factor affecting sway is yaw DAMPING and there are several effective methods to improve damping and thus sway stability. Vehicle mass an important one, but by no means the most important. In rough order of importance factors a buyer/driver can influence are:

1. Vehicle speed, because this directly contributes to trailer yaw inertia, and vehicle pitch.
2. Trailer center of gravity location, Too little mass in front of the trailer axles which are the anchor point for trailer yaw moments creates a situation where there is nearly no yaw damping (resistance to side motions).
3. Hitch point yaw resistance. A Hensley type hitch has nearly 100% resistance to trailer induced yaw. Other hitches have good resistance and some have much less resistance.
4. Vehicle mass. The trailer inertia must overcome the mass of the vehicle in order to induce yaw velocity which initiates a potential sway event.
5. Vehicle tire sidewall stiffness. Soft sidewalls or under inflated tires allow harmful oscillatory pitch moments which induce secondary yaw velocities with very destructive periodicity.
6. Vehicle center of gravity. Low and close to the mid point of the wheel base provides the ideal resistance to trailer inertia.
7. Vehicle geometry. Long wheel base with short distances from the rear axle to the trailer ball is ideal.

It is quite possible to make up for a deficiency in one of the factors above by improving one or more of the others.

No need to thank me, out of site, I'm always happy to help you with your technical shortcomings and difficulty you have with your explanations.

[Countryboy59]

Originally Posted by overlander63

The trailer only has brakes if they are functioning. A little dirt or corrosion in the plug, a bump in the road to jostle the connector, and suddenly a kid on a tricycle rolls out in front of you. I don't care it your trailer has the best brakes in the world, if they aren't working, it's just like only having the tow vehicle brakes. I'm thinking of the newer F150 with the inverted trailer connector plug, where the plug loses connection if you run over a pebble in the road. By coincidence, one of the trucks espoused in this thread as being a great towing vehicle.

It has happened.
I have witnessed it.
It has happened to others on this forum.

It’s easy to check for an intermittent trailer connector. Loss of connection shouldn’t happen with proper maintenance and if you’re not doing that, you shouldn’t be towing.

[lsbrodsky]

Ha! Ha!

Brian, good stuff! But, I have a serious question after reflecting on your list. I have seen heavy trucks pulling a lightweight boat on a trailer with just a standard ball hitch...and significant sway. It appears that all of your truck factors except speed are irrelevant as the appearance is that the boat trailer is just an independent pendulum swinging in the breeze. What is that boat owner to do except slow down?

Larry

[Fair_Enough]

Originally Posted by Kalashnikov

Conclusion: You don't _need_ to spend 10k more on that 3/4 ton truck if you're towing 9k pounds or less.

That should cover most AS owners

Preaching to the choir, K. Towing a 6K 23FB (with the 3.5L TT) has netted me 14.6 MPG from Florida to Doswell and back. Typically 13.5 MPG, however. I have seen 31 MPG not towing that is a typically 26.5 MPG interstate. With a Hensley hitch, it tows marvelously and stops amazingly. The 6.5 seconds zero to 60 smokes your stock super duty and always results in a silly grin on my face.... and my 2018 2wd cost right around $40K.
WW

[out of sight]

I recently passed a boat being towed on the highway. It had four 400 hp outboard motors hanging off the back. So there is the problem with boat towing - much of the load is on the rear behind the trailer wheels. The trailer has to have a real long tongue to achieve stability, but even then it may not be possible to go very fast without swaying.

This is not a problem with modern Airstreams. It is almost impossible to load the trailer that way and create dangerous sway.

[BayouBiker]

Yeah Larry, that's a great observation and a good opportunity to test the list...

So when the trailer is so light and has so little mass located any appreciable distance from the trailer center of gravity (and thus very low yaw inertia), that it simply can't overcome the vehicle inertia, and the vehicle simply drags it around like a rag doll, some people tend to pull the trailer too fast.

The trailer itself is clearly above its critical speed and is bucking back and forth to no avail. Factor 4, vehicle mass, has overpowered factor 2, trailer weight distribution. So to fix this, they should slow down (add some of factor 1) because those trailers are not designed to go that fast, but they won't so...

They should add or move some weight to the front of the trailer and keep adding it until the trailer tows nice at the speed the driver prefers. One problem they may run into is they exceed the axle or tire weight limits.

[Profxd]

Originally Posted by BayouBiker

Here let me fix this for you....

Many factors affect stability of a towing system. The main factor affecting sway is yaw DAMPING and there are several effective methods to improve damping and thus sway stability. Vehicle mass an important one, but by no means the most important. In rough order of importance factors a buyer/driver can influence are:

1. Vehicle speed, because this directly contributes to trailer yaw inertia, and vehicle pitch.
2. Trailer center of gravity location, Too little mass in front of the trailer axles which are the anchor point for trailer yaw moments creates a situation where there is nearly no yaw damping (resistance to side motions).
3. Hitch point yaw resistance. A Hensley type hitch has nearly 100% resistance to trailer induced yaw. Other hitches have good resistance and some have much less resistance.
4. Vehicle mass. The trailer inertia must overcome the mass of the vehicle in order to induce yaw velocity which initiates a potential sway event.
5. Vehicle tire sidewall stiffness. Soft sidewalls or under inflated tires allow harmful oscillatory pitch moments which induce secondary yaw velocities with very destructive periodicity.
6. Vehicle center of gravity. Low and close to the mid point of the wheel base provides the ideal resistance to trailer inertia.
7. Vehicle geometry. Long wheel base with short distances from the rear axle to the trailer ball is ideal.

It is quite possible to make up for a deficiency in one of the factors above by improving one or more of the others.

No need to thank me, out of site, I'm always happy to help you with your technical shortcomings and difficulty you have with your explanations.

You are correct in that many things contribute to stability. Increasing TV unladen mass is one of the best things you can do to the TV to raise critical speed. A properly designed TV with 1500 lbs + higher mass can easily raise that critical speed by 15 mph when everything else remains constant.

The contributions specifically are.
1) Better overall TV/trailer mass ratio.
2) Higher cornering stiffness generated at the tires
3) Longitudinal COG position stays further forward away from the rear axle. WB dependent.
4) Increased suspension stiffness in both the vertical and horizontal plane.

This is why the switch to a class 2b TV has worked for many, but as the trailer dictates it won’t work all the time. Characteristics of both TV and trailer must be considered to quantify stability.

[out of sight]

Originally Posted by BayouBiker

Here let me fix this for you....

Many factors affect stability of a towing system. The main factor affecting sway is yaw DAMPING and there are several effective methods to improve damping and thus sway stability. Vehicle mass an important one, but by no means the most important. In rough order of importance factors a buyer/driver can influence are:

1. Vehicle speed, because this directly contributes to trailer yaw inertia, and vehicle pitch.
2. Trailer center of gravity location, Too little mass in front of the trailer axles which are the anchor point for trailer yaw moments creates a situation where there is nearly no yaw damping (resistance to side motions).
3. Hitch point yaw resistance. A Hensley type hitch has nearly 100% resistance to trailer induced yaw. Other hitches have good resistance and some have much less resistance.
4. Vehicle mass. The trailer inertia must overcome the mass of the vehicle in order to induce yaw velocity which initiates a potential sway event.
5. Vehicle tire sidewall stiffness. Soft sidewalls or under inflated tires allow harmful oscillatory pitch moments which induce secondary yaw velocities with very destructive periodicity.
6. Vehicle center of gravity. Low and close to the mid point of the wheel base provides the ideal resistance to trailer inertia.
7. Vehicle geometry. Long wheel base with short distances from the rear axle to the trailer ball is ideal.

It is quite possible to make up for a deficiency in one of the factors above by improving one or more of the others.

No need to thank me, out of site, I'm always happy to help you with your technical shortcomings and difficulty you have with your explanations.

I think one of your problems in understanding towing stability is that all you are considering is trailer instability (sway). Go back to the chart and contemplate what is indicated there as tow vehicle instability. This is what happens when you round a turn and the inertia of the trailer, which wants to go straight, pushes the rear of the truck sideways, leading to oversteer and potential jackknife. Sway in an Airstream is not dangerous, it's has more to do with what makes the driver uncomfortable. But tow vehicle stability can lead to an accident when the driver needs to make a sharp swerve. All of these hitches that address trailer stability make tow vehicle stability worse.

[mkcurtiss]

Vehicle weight is very important. as trailer weights get over 5000 lb.

The F-250 will do the job much longer than the f 150....you will tear up the 150. end of story.

[ROBERT CROSS]

Originally Posted by mkcurtiss

.......you will tear up the 150. end of story.

Your story something more than a wild guess but less than a well-established theory.


Bob
🇺🇸

[BayouBiker]

Originally Posted by out of sight

I think one of your problems in understanding towing stability is that all you are considering is trailer instability (sway). Go back to the chart and contemplate what is indicated there as tow vehicle instability. This is what happens when you round a turn and the inertia of the trailer, which wants to go straight, pushes the rear of the truck sideways, leading to oversteer and potential jackknife. Sway in an Airstream is not dangerous, it's has more to do with what makes the driver uncomfortable. But tow vehicle stability can lead to an accident when the driver needs to make a sharp swerve. All of these hitches that address trailer stability make tow vehicle stability worse.

Here let me fix this for you....

Brian, I appreciate your expertise and understanding of kinematic systems, mechanics and feedback control, but sway is only one of several factors affecting vehicle safety while towing. Others are steering response, cornering stability, braking performance, collision avoidance and vehicle capability (resistance to overheating and overloading engine, transmission, axles, etc.).

Fortunately your list works for steering and cornering also, though hitch point yaw resistance drops a couple notches and the Hensley hitches don't offer any significant resistance to yaw initiated by the vehicle in a corner or emergency maneuver. This is why some people with Hensley type hitches get into trouble, they let themselves get overconfident with the performance of the hitch and drive too fast but it can't help them when they experience oversteer.

Thus drivers need to understand that rear tow trailers dramatically reduce the theoretical speeds at which both front tire slip (understeer) and rear tire slip (oversteer) occurs. So depending on the situation, the one that occurs first dominates. A Weight Distribution hitch restores vehicle geometry and in a sense improves understeer by increasing front tire hold, but it cannot help with oversteer since it is induced primarily by trailer yaw inertia. The net outcome is that with a WD hitch safe handling speed is improved (increased) but the system is much more likely to experience oversteer rather than understeer and drivers must be aware of this. They should either avoid it by not exceeding the safe speed for weather and vehicle conditions or know how to properly respond to oversteer.

Safety studies indicate drivers respond much better to understeer and the resulting accidents are much less severe. Vehicle manufacturers are therefore required to recommend rig configurations that ensure understeer at posted speed limits.

Sway can be a significant issue for all rear tow trailers weighing more than 5000 lbs which includes most Airstreams. For any configuration there is a critical speed where below that speed there is no sway or sway damps out after a couple oscillations. Above the critical speed, sway amplifies catastrophically ending in a serious accident. By applying best practices to the list Brian provided, one can dramatically improve sway and handling critical speeds. Hitch choice is one factor and properly set up, most hitches will improve system performance by all relevant measures.

Brian, I would never state or imply you have trouble understanding these important safety issues.

[out of sight]

Here are some reasons why weight distribution/sway hitches decrease tow vehicle stability.

W/d removes weight from the tow vehicle rear axle where it is needed to control the inertia of the trailer. Removing weight from the tires decreases sidewall stiffness and causes oversteer. Decreasing the force on the tire decreases the tire friction force between tire and road surface leading to breaking of traction and creating an accident.

W/d hitches all extend the distance from the tow vehicle axle to the articulation point, some by more than a foot, giving the trailer a greater lever with which to push the trailer around.

W/d hitches are heavy and add to tongue weight. Increasing tongue weight increases tow vehicle instability by increasing the perpendicular force on the lever.

[olgoat]

I just come here for the comic relief.

BTW my F-250 tows with a level of confidence, that my F-150 never had. Can an F-150 get the job done, sure. With my tow rig combo, my hitch selection, my driving habits and my towing environment I am happy with the F-250. If a 1/2 ton truck works for you, by all means use it, just stay within the vehicle ratings.

[TravelNew20]

Originally Posted by Kalashnikov

Official test:

Conclusion: You don't _need_ to spend 10k more on that 3/4 ton truck if you're towing 9k pounds or less.


That should cover most AS owners

I am new here & hope that my P-Truck research turns out to be correct. I created a spread sheet with the big-3 manufacturers’ approximate price, HP, torque ratings, max loads & etc. I purchased a 2019 F-150 3.5 EB (Max Tow). My understanding is that many ½ ton trucks CAN tow but the question is can you stop with your load. I have been told that if you’re unloaded / dry weight is at or > 7000 lbs. then one needs a ¾ ton truck. We have a 25’ International RBT on order with a 5250 lb. dry weight & ~ 7600 lb. loaded. This give me ~ 5000 lbs. margin with the trucks 12,700 lbs. tow rating. I also added 1500 lb. Sumo Springs due to F-150s tendency to “squat” under load… Will have a WD + anti-sway hitch. I will find out as soon as Airstream Factory opens up again.

[Mollysdad]

Originally Posted by overlander63

The trailer only has brakes if they are functioning. A little dirt or corrosion in the plug, a bump in the road to jostle the connector, and suddenly a kid on a tricycle rolls out in front of you. I don't care it your trailer has the best brakes in the world, if they aren't working, it's just like only having the tow vehicle brakes. I'm thinking of the newer F150 with the inverted trailer connector plug, where the plug loses connection if you run over a pebble in the road. By coincidence, one of the trucks espoused in this thread as being a great towing vehicle.

It has happened.
I have witnessed it.
It has happened to others on this forum.

My goodness, you've created a scenario where the window of success is very narrow. You're opining that IF the tow vehicle was a F-250, and the trailer brakes failed, and a kid ran out in front of you, you'd stop in time?
There's no science to test that. Kids run out at varying distances. Some escape with both vehicles, some get clobbered by both vehicles, some escape but you get rear ended by a semi. and yes, there's that perfect 10' where the kid survives the F-250 but gets bonked by the F-150.
We all manage risk. It's dangerous to own a swimming pool, take showers, drive on the interstate or swim in the ocean.

[gypsydad]

Originally Posted by SandKSmith

Not to highjack a thread, but the subject seems have gone to 1/2 ton trucks and often a 25’ or larger Airstream, safety, and braking on mountain passes so here goes: I-17 between Phoenix and Flagstaff, Highway 89 between Fountain Hills and Payson, highway 260 east of Payson all have 6%+ grades, some on which go on for miles. Lots of curves too. We traveled these many times last year in 2019 Ram 1500 and 25’ 2006 Safari. Never had an issue going up or down these hills. Plenty of power going up, plenty of control going down. I’ve found that the 8 speed transmission is well programmed: touch the brakes and it drops a gear. Tough them again, and it drops another. I can hold any gear I want. Granted the engine is turning 3500-4000 rpm, but so what? I’m not riding the brakes, not going too fast, no white knuckles. It’s comfortable. The engine drone gets a bit old, but it’s only for a few miles. I rarely need to touch the brakes. It does the job and is a great daily driver.

I was planning a trip this summer through the Rockies. I don’t know now if/when that will happen anymore, and it’s been 35 years since I’ve driven any of those mountain passes. Based on our Northern AZ experience, I expected pretty much the same performance, as the Monarch and 550 passes appear to be 6 or 7% grades. There will be a significant altitude change between 5000-7000 ft in Az and the 11,000+ in the Rockys, and the Hemi, being normally aspirated, will likely struggle a bit with the thinner air. Someone noted trucks have changed a lot in recent years. I believe that’s true. Are my expectations optimistic?

Thanks
Steve

I think your 25' with that 1/2T is a great combo...what is your Payload rating on the doorjam? Most 1/2T RAM's I looked at couple years back were hard pressed to offer more then 1300lb rating...maybe things have changed? But, still, for a 25' you should be fine...I miss driving around with a smaller TV for sure.

[kscherzi]

Originally Posted by overlander63

The trailer only has brakes if they are functioning. A little dirt or corrosion in the plug, a bump in the road to jostle the connector, and suddenly a kid on a tricycle rolls out in front of you. I don't care it your trailer has the best brakes in the world, if they aren't working, it's just like only having the tow vehicle brakes. I'm thinking of the newer F150 with the inverted trailer connector plug, where the plug loses connection if you run over a pebble in the road. By coincidence, one of the trucks espoused in this thread as being a great towing vehicle.

It has happened.
I have witnessed it.
It has happened to others on this forum.

And what if you're towing an 28 foot airstream down a narrow nine mile long twisting 12% grade in freezing rain late on a moonless night at 65 mph when suddenly the trailer brakes go out. There just ahead is a sharp 25 mph turn protected by a thin piece of bent rusty guardrail past which is the deadly 2,000 foot cliff of doom.

Which would you rather be driving, a F150 or F250?

[gypsydad]

Originally Posted by TravelNew20

I am new here & hope that my P-Truck research turns out to be correct. I created a spread sheet with the big-3 manufacturers’ approximate price, HP, torque ratings, max loads & etc. I purchased a 2019 F-150 3.5 EB (Max Tow). My understanding is that many ½ ton trucks CAN tow but the question is can you stop with your load. I have been told that if you’re unloaded / dry weight is at or > 7000 lbs. then one needs a ¾ ton truck. We have a 25’ International RBT on order with a 5250 lb. dry weight & ~ 7600 lb. loaded. This give me ~ 5000 lbs. margin with the trucks 12,700 lbs. tow rating. I also added 1500 lb. Sumo Springs due to F-150s tendency to “squat” under load… Will have a WD + anti-sway hitch. I will find out as soon as Airstream Factory opens up again.

FYI- we purchased a "new" 2012 Platinum 4x4 EB with our second 25' Safari, several years ago, then purchased a new 2014 25' FC Twin back in the day and owned for 3 more years, thru early 2017; 130+K miles on the F150. towed the 25's great. Only area of issue, was the actual "max payload" on the doorjam sticker, was only 1039lbs...I learned here on the Forum after owning for 3 years, that I had been driving "overloaded" by 300-400lbs most of the time when towing! Truck did fine, and was a pleasure to drive....Note: How many times we have read here on the Forum, where the "new owner" of a 1/2T missed the actual "payload" of his particular truck is numerous! Fool me once...as the saying goes..and that's why we got a new F250 6.7L when we moved up to a 28' FC in June of 2017. Happy wife also..which is important!

[BayouBiker]

I'll just fix this directly. You're welcome...

Originally Posted by out of sight

Here are some reasons why weight distribution/sway hitches can influence tow vehicle stability.

W/d removes weight from the tow vehicle rear axle where it could otherwise contribute to control the inertia of the trailer. Removing weight from the lightly loaded tires decreases sidewall stiffness but most situations haulers encounter stiffness is flat in the load range under consideration, so I'm not sure where I'm going with this. Decreasing the force on the tire decreases the tire friction force between tire and road surface leading to breaking of traction but there is a complex trade off between front and rear. As Brian indicated, the net effect usually is improved vehicle traction.

W/d hitches all extend the distance from the tow vehicle axle to the articulation point, some by more than a foot, giving the trailer a greater lever with which to push the trailer around.

W/d hitches are heavy and add to tongue weight. Increasing tongue weight increases tow vehicle instability by increasing the perpendicular force on the lever, fortunately this can be reversed and eliminated by distributing it and with yaw resistance.

There, much better.