Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-16-2019, 01:05 PM   #61
2020 Classic 33 on order
 
Box Elder , South Dakota
Join Date: Oct 2013
Posts: 1,583
Images: 1
Uncle_bob, the great thing about the forum is that they have an ignore list. With the age old saying of 'out of sight out of mind' I started using that feature and reading is much more enjoyable.
__________________

__________________
Gary
2020 Classic 33 Twin, 2019 Ram 3500 Longhorn, ProPride
NØVPN
ghaynes755 is offline   Reply With Quote
Old 09-16-2019, 04:41 PM   #62
Wolfwhistle
 
Wolfwhistle's Avatar
 
Margaritaville , Banana Republic
Join Date: Jul 2018
Posts: 496
Tongue Weight with Weight Distributing Hitches

I just read back in the thread a few lightyears. I read “Trailers are designed so 10% to 15% tongue weight”. First where in the world did you find a designed trailer. My little 23FB fresh from JC- weighted 4806# with tongue weight of 467#. When I went to school that is under 10%. Reality is when gross is at the limit (6K#) the TW will be 600# and can be ”tweaked” to the north side of 10% TWR. But blanket statement that sound authoritative are suspect. Did I read that a trailer should never be over 110% heavier than it’s TV. Someone should call the majors brands and tell them they are screwing up. I need a F250 to tow a 23FB. Darn, I’m going to have to sell it all. Wait til I inform my naive brother in law that he needs an M1 Abraham to tow their 18,000 lb 5th wheel. He’s been darn lucky he hadn’t killed anyone towing with a Freightliner Sport Chassis. You can learn a lot on these kinds of forums.
__________________

__________________
Ford and 23 FB IS
Wolfwhistle is offline   Reply With Quote
Old 09-17-2019, 11:29 AM   #63
Half a Rivet Short
 
2017 30' Classic
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 8,511
Quote:
Originally Posted by out of sight View Post
I was talking 1:1, not 1.5:1. That's an F250.
Hi

So what does one buy to "properly" pull a 10,000 lb Classic if a 250 is barely good enough for a < 25' trailer ? A 450 isn't going to do the job.

Bob
uncle_bob is offline   Reply With Quote
Old 09-17-2019, 06:52 PM   #64
Rivet Master
 
2019 28' Flying Cloud
2014 22' FB Sport
Davie , FL
Join Date: Feb 2019
Posts: 697
If you want to bumper pull a 10,000 lb trailer at highway speeds and still be perfectly safe you need to find a 10,000 lb tow vehicle.
out of sight is offline   Reply With Quote
Old 09-18-2019, 12:05 AM   #65
Rivet Master
 
bhayden's Avatar
 
1978 24' Argosy 24
Woodinville , Washington
Join Date: May 2006
Posts: 675
Images: 10
So I keep hearing some weight is transferred to the front tires of the TV (let's not assume there's an axle there but same thing). And "some" weight is transferred to the trailer. While that's true what's left without saying is that with a tandem axle trailer "some" weight is transferred to the rear axle tires of the trailer (and relieved from the front tires).


So, with the axles being so close together on the trailer, is there an issue with overloading the rear tire load capacity?
bhayden is offline   Reply With Quote
Old 09-18-2019, 12:13 AM   #66
Rivet Master
 
bhayden's Avatar
 
1978 24' Argosy 24
Woodinville , Washington
Join Date: May 2006
Posts: 675
Images: 10
An F350 diesel does a fine job pulling a 10,000# trailer (been there, done that). The idea that the TV has to out weigh the trailer assumes the trailer has no brakes. A good electric brake setup is more important than a WD hitch when talking about a decently loaded trailer and a capable TV.
bhayden is offline   Reply With Quote
Old 09-18-2019, 07:28 AM   #67
Wolfwhistle
 
Wolfwhistle's Avatar
 
Margaritaville , Banana Republic
Join Date: Jul 2018
Posts: 496
Quote:
Originally Posted by bhayden View Post
So I keep hearing some weight is transferred to the front tires of the TV (let's not assume there's an axle there but same thing). And "some" weight is transferred to the trailer. While that's true what's left without saying is that with a tandem axle trailer "some" weight is transferred to the rear axle tires of the trailer (and relieved from the front tires).


So, with the axles being so close together on the trailer, is there an issue with overloading the rear tire load capacity?
Having weighed both Torflex and "conventional" tandem axle trailers. I have observed that the weight carried by the pair is pretty well balanced on the axle pair. Nose up or down affects Torflex more than conventional and can cause some difference. That is why axles and tires should have a safety margin, not even considering that left and right will be different, as well.

Lets say hypothetically you have 1000# of TW and the tow vehicle (TV) is now nose high and the rear squatting. This TW plus the weight shifted from the steering to drive axle has occurred. Lets say that now the drive axle has 1250# of added weight on it. So, you now want to move 500# of that TW off of the drive axle with WDH. Then... about 250# will be added to the steering axle (its not an assumption), probably better to say moved 250# back to the steer axle, and 250# will be moved to the trailer axle pair, and if level, 125# to each axle. Or in the ballpark of 62-63# to each trailer tire. Whether in reality that ends up being 275# to the steer and only 225# to the trailer is not critical and is a matter of physics. Ball to center of axle pair and ball to steering axle distance is what it is.

Clint
__________________
Ford and 23 FB IS
Wolfwhistle is offline   Reply With Quote
Old 09-18-2019, 08:47 AM   #68
Rivet Master
 
2019 28' Flying Cloud
2014 22' FB Sport
Davie , FL
Join Date: Feb 2019
Posts: 697
On a tandem axle trailer the loads on the rear trailer axle and front trailer axles will be equal whenever the trailer is level. If the nose is down the front axle gets more load and if the nose is up he rear axle gets more load.

The tongue weight also changes as the trailer level changes. If the nose is up the trailer is now pivoting more about the rear axle which is further away from the tongue, and the tongue weight is greater. If it's down it's pivoting more about the front axle and the tongue weight is lower.

It's important that the trailer is as level as possible after hitching up. That way the front and rear tires are equally loaded.
out of sight is offline   Reply With Quote
Old 09-18-2019, 11:05 AM   #69
Half a Rivet Short
 
2017 30' Classic
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 8,511
Quote:
Originally Posted by out of sight View Post
If you want to bumper pull a 10,000 lb trailer at highway speeds and still be perfectly safe you need to find a 10,000 lb tow vehicle.
Hi

....and since those vehicles don't exist, I guess nobody should ever buy a trailer (RV or otherwise) that weighs that much .....

Again, we're not just talking about Airstreams here. There are a whole lot of farm trailers out there.

Bob
uncle_bob is offline   Reply With Quote
Old 09-18-2019, 01:00 PM   #70
Rivet Master
 
2019 28' Flying Cloud
2014 22' FB Sport
Davie , FL
Join Date: Feb 2019
Posts: 697
If your tow vehicle is on the small side that doesnt mean you can't tow. It just means that you shouldn't be travelling at highway speeds, which in the US is up to 80 MPH. Keep it to 60 mph if you want to tow a 10,000 lb trailer with an F 350.
out of sight is offline   Reply With Quote
Old 09-18-2019, 02:07 PM   #71
3 Rivet Member
 
2019 27' International
Western , North Carolina
Join Date: Jun 2019
Posts: 165
Images: 1
Quote:
Originally Posted by out of sight View Post
If your tow vehicle is on the small side that doesnt mean you can't tow. It just means that you shouldn't be travelling at highway speeds, which in the US is up to 80 MPH. Keep it to 60 mph if you want to tow a 10,000 lb trailer with an F 350.


Did you mean F150???? A F350 can tow 10k all day long.
__________________
2019 International Serenity 27 FBQ “Serenity”

2019 Ford F-350 Platinum
JonDNC is offline   Reply With Quote
Old 09-18-2019, 02:23 PM   #72
2020 Classic 33 on order
 
Box Elder , South Dakota
Join Date: Oct 2013
Posts: 1,583
Images: 1
Well the trucking industry must not be getting OOS's memo's about weight. That's why they can't tow a trailer behind a Kenworth T800, which has a vehicle weight of about 20,000# with fuel, that weighs more that 20,000# with cargo. Such lack of professional knowledge. Just pointing out that with the proper permits, etc. the T800, according to Kenworth, can safely tow 300,000#. "That's why your T800 starts as a clean sheet of paper, its wheelbase custom tailored to your specifications. Your design choices encompass the latest technologies and a spectrum of proven heavy-duty components for GCWs to 330,000 pounds. -
https://www.kenworth.com › media › kenworth_t800_brochure.pdf"


My mantra "oos, oom". Now if only I figure out how to use the ignore setting within a post so I don't read his reposts.
__________________
Gary
2020 Classic 33 Twin, 2019 Ram 3500 Longhorn, ProPride
NØVPN
ghaynes755 is offline   Reply With Quote
Old 09-18-2019, 03:01 PM   #73
Rivet Master
 
2019 28' Flying Cloud
2014 22' FB Sport
Davie , FL
Join Date: Feb 2019
Posts: 697
I thought I'd post what the professionals are saying, for those people who don't know the difference between a travel trailer and a semi.

This is from U-Haul:

For occasional towing, your vehicle, when properly equipped, can tow any recommended U-Haul trailer, if the loaded weight of the trailer does not exceed your vehicle’s curb (empty) weight. Your vehicle can also tow any U-Haul trailer equipped with brakes, provided the curb weight of your tow vehicle is at least 80% of the loaded weight of the braked trailer.

This is from NATM:
Attached Thumbnails
Click image for larger version

Name:	Towing Stability Graph.jpg
Views:	17
Size:	134.8 KB
ID:	352448  
out of sight is offline   Reply With Quote
Old 09-18-2019, 04:01 PM   #74
Lost in America
 
mojo's Avatar
 
2015 27' FB International
2006 25' Safari FB SE
2004 19' International CCD
Santa Fe , New Mexico
Join Date: Feb 2007
Posts: 1,747
And U-Haul says not to exceed 45mph when towing their trailers.
__________________
This is the strangest life I've ever known - J. Morrison

2015 Airstream International Serenity 27FB
2017
Chevy Silverado 2500HD Duramax Diesel

mojo is online now   Reply With Quote
Old 09-18-2019, 06:41 PM   #75
jcl
Rivet Master
 
Currently Looking...
Vancouver , British Columbia
Join Date: Oct 2012
Posts: 1,952
Quote:
Originally Posted by out of sight View Post
I thought I'd post what the professionals are saying, for those people who don't know the difference between a travel trailer and a semi.

This is from U-Haul:

For occasional towing, your vehicle, when properly equipped, can tow any recommended U-Haul trailer, if the loaded weight of the trailer does not exceed your vehicle’s curb (empty) weight. Your vehicle can also tow any U-Haul trailer equipped with brakes, provided the curb weight of your tow vehicle is at least 80% of the loaded weight of the braked trailer.

This is from NATM:
It is very concerning that you don't know the difference between a U-Haul cargo trailer and a travel trailer in terms of towing setup.

U-Haul allows the trailer weight to exceed the tow vehicle weight by 25% if you are towing one of their trailers with brakes. Those brakes are surge brakes by definition, and so the relative weights matter for activation of the trailer brakes. Of course those surge brakes are also why they don't use WD equipment, since it isn't compatible with surge brakes.

U-Haul limits the trailer weight to the tow vehicle weight if you are towing one of their trailers without any brakes. In many jurisdictions, that is illegal anyway. Trailer brakes are generally required over a certain trailer weight.

And you extrapolate this to travel trailers, which have electric trailer brakes, and simultaneously criticize people who don't distinguish between different types of trailers.

You should also qualify what types of trailers NATM is discussing. Any stability graph which makes no reference to bluff area, towing speed, rear axle to hitch ball distance, tow vehicle wheelbase, type of hitch, tow vehicle tire characteristics, etc, and presumes to relate stability to only tongue weight and the ratio of TV weight to trailer weight, is of no value and contributes nothing to the discussion.
jcl is offline   Reply With Quote
Old 09-19-2019, 11:14 AM   #76
Half a Rivet Short
 
2017 30' Classic
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 8,511
Hi

Rules like "45 mph max" and the U-Haul weight limits come more from various state regulations than they do from any detailed analysis of what's what. Those regulations may or many not have been designed to cover various corner cases. Hooking a trailer up to a vehicle that was never designed to tow anything at all is very different than hooking to a vehicle that *does* have tow ratings.

Bob
uncle_bob is offline   Reply With Quote
Old 10-18-2019, 06:07 PM   #77
2020 Flying Cloud 27FBT
 
2020 27' Flying Cloud
Howell , MI
Join Date: Oct 2019
Posts: 11
Quote:
Originally Posted by Profxd View Post
Why 10% TW? The purpose of setting any percentage of TW is because it sets the position of the trailer center of gravity. Let’s say effective tongue length is 200 in. which is measured from coupler to the axle centerline. 10% TW would position the trailer center of gravity at 20 in. forward or the axle centerline, at 15% it will be 30 in. forward of the axle centerline.
So the trailer center of gravity is point at which the trailer wants to rotate if some lateral force pushes on it. The closer the center of gravity is to the trailer axle centerline the easier it is to rotate it causing instability. If the trailer center of gravity is at or behind the axle centerline it drastically reduces the speed that instability occurs.

The equations for COG positioning can be found in this paper. https://pdfs.semanticscholar.org/4e8...336eef1e34.pdf
There are graphs in it for stability at various trailer COG positions
Thanks for posting this link to the SAE paper. I read it all the way through. Good, solid engineering stuff.
BandLAir is offline   Reply With Quote
Old 10-18-2019, 06:29 PM   #78
3 Rivet Member
 
Currently Looking...
Baltimore , Maryland
Join Date: Nov 2017
Posts: 146
Quote:
Originally Posted by BandLAir View Post
Thanks for posting this link to the SAE paper. I read it all the way through. Good, solid engineering stuff.
Your welcome! Here is another good one.https://tuprints.ulb.tu-darmstadt.de...ssertation.pdf
Profxd is offline   Reply With Quote
Old 10-19-2019, 02:01 AM   #79
1 Rivet Member
 
Currently Looking...
Warren , New Jersey
Join Date: Sep 2019
Posts: 14
The Delphi paper linked was about verifying a computer model to develop ESC software, not a meaningful analysis of trailer stability. The doctoral thesis linked really doesn't have any meaningful analysis of the parameters. The most extensive research that was on point was done in the 1970s and is available online, although I don't have the links readily available.

I've been a bit too busy to finish my model, but have had one WD hitch manufacturer tell me their target is 4.5%-5.5% tongue weight after adjustment. That would be 6%-7% disconnected.

The key is keeping the mass at the rear of the trailer low and maintaining capacity in the rear wheels of the tow vehicle. GAWR is generally at a limit where the non-LT tires and the springs are at their max. The other is keeping the pivot point/virtual pivot point of the trailer close to the rear axle. 5th wheel/gooseneck trailers have either over the rear wheels are within 22" (for a turret 5th wheel pin box) compared to 60+" for a typical bumper pull. A Hensley or ProPride hitch will move the horizontal pivot within a foot or so of the rear axle and are very stable. There are threads on this forum about them.

A dually will have around 10k# rear GAWR with maybe 6000+# available. Dropping a 1000# tongue weight on it won't phase it. A 1/2 ton will typically have around a 4k# rear GAWR with maybe 1400# available. It is very easy to bring that to its limit. Adding airbags or Timbrens, LT-tires, and maybe higher load rated wheels would add stability.

Kelderman specs a large rear anti-roll bar for their 4-link/airbag rear suspension for HD pickups. The purpose is to control roll. Their setup appears to be popular for horse trailers. Some people have added stiffer front anti-roll bars with a bump-pull on a 1/2 ton to increase understeer. Understeer is a frequently used measurement of towing stability. It shouldn't be necessary with a Hensley or ProPride.
DavidNJ is offline   Reply With Quote
Old 10-19-2019, 06:26 AM   #80
3 Rivet Member
 
Currently Looking...
Baltimore , Maryland
Join Date: Nov 2017
Posts: 146
Quote:
Originally Posted by DavidNJ View Post
The Delphi paper linked was about verifying a computer model to develop ESC software, not a meaningful analysis of trailer stability. The doctoral thesis linked really doesn't have any meaningful analysis of the parameters. The most extensive research that was on point was done in the 1970s and is available online, although I don't have the links readily available.

I've been a bit too busy to finish my model, but have had one WD hitch manufacturer tell me their target is 4.5%-5.5% tongue weight after adjustment. That would be 6%-7% disconnected.

The key is keeping the mass at the rear of the trailer low and maintaining capacity in the rear wheels of the tow vehicle. GAWR is generally at a limit where the non-LT tires and the springs are at their max. The other is keeping the pivot point/virtual pivot point of the trailer close to the rear axle. 5th wheel/gooseneck trailers have either over the rear wheels are within 22" (for a turret 5th wheel pin box) compared to 60+" for a typical bumper pull. A Hensley or ProPride hitch will move the horizontal pivot within a foot or so of the rear axle and are very stable. There are threads on this forum about them.

A dually will have around 10k# rear GAWR with maybe 6000+# available. Dropping a 1000# tongue weight on it won't phase it. A 1/2 ton will typically have around a 4k# rear GAWR with maybe 1400# available. It is very easy to bring that to its limit. Adding airbags or Timbrens, LT-tires, and maybe higher load rated wheels would add stability.

Kelderman specs a large rear anti-roll bar for their 4-link/airbag rear suspension for HD pickups. The purpose is to control roll. Their setup appears to be popular for horse trailers. Some people have added stiffer front anti-roll bars with a bump-pull on a 1/2 ton to increase understeer. Understeer is a frequently used measurement of towing stability. It shouldn't be necessary with a Hensley or ProPride.
David to say there’s nothing meaningful in those papers is nonsense. The STM is standard physics, the calculations for sway damping ratio are there. I’m glad you’re going to create a model that works since everyone has been doing it wrong all these years.
__________________

Profxd is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tow vehicle Tongue Weight vs. Trailer Tongue Weight KeepPedaling Hitches, Couplers & Balls 10 03-23-2016 01:33 PM
From the Noob desk: weight vs. weight distributing TINLOVE Hitches, Couplers & Balls 5 10-12-2014 11:10 PM
Question about weight distributing hitches and sway bars wacnstac Hitches, Couplers & Balls 1 02-17-2006 07:35 AM
European Weight Distributing hitches 85MH325 Hitches, Couplers & Balls 10 11-17-2004 08:43 AM
weight distributing hitches jack simons Hitches, Couplers & Balls 11 10-22-2003 01:10 AM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 09:49 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.