Trailer Weight Distribution - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 10-06-2016, 08:06 AM   #1
Senior Member
 
dleverton's Avatar
 
Name: Doug
Trailer: Trillium 1300 1973
British Columbia
Posts: 185
Registry
Trailer Weight Distribution

I love this video demonstration.
This is a dynamic that most people that have done a lot of towing are aware of. When we were towing rally cars on single axil trailers, we could easily load the car fore or aft and so managed to conclude that fore was stable compared to aft. Designers of electronic control systems have mathematical algorithms for resolving very similar issues, but they can be tedious and complex. I love the simplicity of this demonstration.
https://m.youtube.com/watch?autoplay=1&v=4jk9H5AB4lM
Click image for larger version

Name:	ImageUploadedByFiberglass RV1475759185.410407.jpg
Views:	78
Size:	193.5 KB
ID:	100386



Doug
__________________

__________________
Doug
dleverton is offline   Reply With Quote
Old 10-06-2016, 09:30 AM   #2
Senior Member
 
reeves99's Avatar
 
Name: Philip
Trailer: Escape 13 /Hyundai Santa Fe
Quebec
Posts: 468
Registry
That's a great video! So simple to understand, yet such an important concept.
__________________

__________________
It's not the size.....
reeves99 is offline   Reply With Quote
Old 10-06-2016, 03:50 PM   #3
Senior Member
 
dleverton's Avatar
 
Name: Doug
Trailer: Trillium 1300 1973
British Columbia
Posts: 185
Registry
Watching the video, its clear that the car has some kind of control algorithm to keep it centred on the treadmill. That algorithm (or the responses of a driver in a full size car/trailer), are also part of the equation involving the instability. A driver can to some extent compensate for the instability of the rig. Also notice that even with the heavy rear load, the rig was able to compensate for a light push (cross wind, road undulation etc.), but a large push could not be recovered. As a much younger person I had an industrial trailer that was clearly unstable. I had no idea at the time why it was unstable and used that trailer for a number of years with a couple of scary incidents. If you have ever had any cyclic sway on your rig, try shifting weight forward. Another cause of instability can be if the wheels on the trailer have some toe-in, or if the front wheels on the tow vehicle have some toe-out. Instability is an event, not a condition, and the event involves all of the conditions (weight distribution, toe, road conditions, driver response, upsetting push). It's possible to drive a marginally stable rig great distances without knowing it can be unstable until a sufficient push comes along. Whenever I drive a new, to me, rig, I wait for a safe bit of road and induce a bit of sway with the steering wheel to see how stable it is, rather than wait for a semi to pass me on the freeway to find out.


Doug
__________________
Doug
dleverton is offline   Reply With Quote
Old 10-06-2016, 05:53 PM   #4
Member
 
Name: Doug
Trailer: 2014 Scamp 16, 2011 RAV4 V6
California
Posts: 44
Great, just as I'm about to install a hitch mounted cargo box on the rear of my Scamp. Actually, it will be a small, light setup and the gear (water hose, filter, chocks, etc.) in it is coming from under the rear dinette bench. Hopefully not a problem. Shorty after getting the trailer I added a rear hitch mount bike rack and two bikes. I took the first freeway exit and dumped the rack and bikes at home. Swayed like crazy. I added an anti-sway bar, just in case, and I don't haul water in the potable water tank anymore. I also plan to add a rack and generator on the tongue, giving more weight up front. Other heavy stuff goes on the floor between the wheels.
Great video.
__________________
Doug in Sacramento is offline   Reply With Quote
Old 10-06-2016, 09:23 PM   #5
Senior Member
 
Bruce H's Avatar
 
Name: Bruce
Trailer: Bigfoot 25 ft RQ
Missouri
Posts: 355
Thanks for posting this Doug in BC. In this case a you tube video is worth a thousand words.

I see that his trailer axle can also be adjusted forward and back on the model. It looks like it is set at about 60/40 with 60% of the tongue or frame length in front of the axle and 40% behind.

Lets do some mental exercises:

What if the trailer axle were slid back to 80/20 and all three of the weights were put on the back? It would be the exact same total trailer weight but how would that affect the tongue weight? Would it still fishtail? What about at 90/10? What about if you slide it forward to 50/50 and do nothing but adjust weights? Which would be the more stable?

While we are at it lets construct a model tow car with a wheel base (distance from the front steering axle to the rear axle) of say 10 inches. Add a draw bar (hitch), with a little ball or hitch pin on the end of it, that can be moved in and out (closer or farther from the rear car axle). Set the trailer weight and tongue length at 60/40 like the you tube guy had it and then try different draw bar distances from the tow car axle, say 10% of the tow vehicle wheel base up to say 50% of the tow vehicle wheel base. What effect would those changes have on trailer stability?

Then if you want to do a really in depth study you can build your model tow vehicle with an adjustable length wheel base and of course adjustable weights front, rear and in the middle. Then you can try all of the length ratios and weight combinations of both the tow vehicle and trailer.

When you complete that course of study you will know more about towing stability dynamics than 99% of trailer manufacturers.
__________________
Bruce H is offline   Reply With Quote
Old 10-06-2016, 11:42 PM   #6
Senior Member
 
dleverton's Avatar
 
Name: Doug
Trailer: Trillium 1300 1973
British Columbia
Posts: 185
Registry
Hey Bruce, wouldn't it be fun to have such a setup as you describe. I'd want adjustable toe as well.


Doug
__________________

__________________
Doug
dleverton is offline   Reply With Quote
Reply

Tags
weight


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
is my weight distribution hitch worth the tongue weight and effort. beachcamper54 Towing, Hitching, Axles and Running Gear 24 01-25-2014 12:41 PM
weight distribution hitches Ian-Vicki Towing, Hitching, Axles and Running Gear 16 07-09-2007 03:47 PM
Single Bar Weight Distribution Hitch Gina D. Towing, Hitching, Axles and Running Gear 33 03-19-2007 01:11 PM
Weight Distribution Trailer Hitch Systems John D. Problem Solving | Owners Helping Owners 1 01-10-2006 04:53 PM
The importance of proper weight distribution Legacy Posts Jokes, Stories & Tall Tales 6 03-21-2003 07:48 AM

» Upcoming Events
No events scheduled in
the next 465 days.
» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:03 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.