Reply
 
Thread Tools Search this Thread Display Modes
 
Old 12-07-2010, 10:33 PM   #1
Rivet Master
Airstream Dealer
 
Inland RV Center, In's Avatar
 
Corona , California
Join Date: Feb 2002
Posts: 16,499
Images: 1
Load Equalizing hitches

Today, we started a research program on load equalizing hitches.

We are measuring the bend in the load equalizing bars, at 100 pound increments, with different brands as well as square and round bars.

The range of the tests start at a low level and up to and including a 20 to 25 percent overload.

We will publish the results as soon as the tests are completed, hopefully by the end of this year.

Andy
__________________

__________________
Inland RV Center, In is offline   Reply With Quote
Old 12-08-2010, 04:31 AM   #2
Rivet Master
 
AIR-Quarius's Avatar
 
1970 27' Overlander
Espanola , Full Timer
Join Date: Jun 2007
Posts: 1,752
Images: 39
Send a message via Yahoo to AIR-Quarius Send a message via Skype™ to AIR-Quarius
Is an equalizing hitch the same as a straight hitch?
__________________

__________________
http://customrvdecalplus.com
AIR-Quarius is offline   Reply With Quote
Old 12-08-2010, 08:41 AM   #3
Rivet Master
Airstream Dealer
 
Inland RV Center, In's Avatar
 
Corona , California
Join Date: Feb 2002
Posts: 16,499
Images: 1
Quote:
Originally Posted by redhawkerII View Post
Is an equalizing hitch the same as a straight hitch?
No.

Andy
__________________
Inland RV Center, In is offline   Reply With Quote
Old 12-08-2010, 09:41 AM   #4
Maniacal Engineer
 
barts's Avatar
 
1971 25' Tradewind
Menlo Park , California
Join Date: Jan 2010
Posts: 1,223
Images: 1
Blog Entries: 4
Great idea... one of my favorite sayings is that one test is worth a thousand expert opinions.

I take it that this will be used to find what engineers call the stiffness of the bar - lbs/inch of flex. Beam theory tells us that this will be a linear relationship.

One of the interesting things we can find out is how much the preload (which is what does the WD function) is affected by a change in pitch angle between the TV and the trailer - which is what happens when the TV encounters a steep driveway or goes over a hill first.

It is my contention that the loads on our AS reduced if a more constant force spring could be used.

- Bart
__________________
Bart Smaalders
Menlo Park, CA
http://tinpickle.blogspot.com
http://smaalders.net/barts
barts is offline   Reply With Quote
Old 12-08-2010, 10:01 AM   #5
Rivet Master
 
dznf0g's Avatar

 
2007 30' Classic
Oswego , Illinois
Join Date: Jul 2010
Posts: 9,401
Images: 5
Quote:
Originally Posted by barts View Post
Great idea... one of my favorite sayings is that one test is worth a thousand expert opinions.

I take it that this will be used to find what engineers call the stiffness of the bar - lbs/inch of flex. Beam theory tells us that this will be a linear relationship.

One of the interesting things we can find out is how much the preload (which is what does the WD function) is affected by a change in pitch angle between the TV and the trailer - which is what happens when the TV encounters a steep driveway or goes over a hill first.

It is my contention that the loads on our AS reduced if a more constant force spring could be used.


- Bart
This will be interesting. Bart, I don't think it will reflect a linear relationship, necessarily. I suspect that some of the tapered bars MAY BE a progressive rate setup. We'll see, because this is information that the MFRs have kept close to the vest. I suspect the round bars and square bars which do not taper or change shape along their length out to the tip will be linear in their deflection until the force nears the max. rating of the bar.

So much is going to be dependant upon the various alloys used in the spring bars also. I think, in previous discussions we all have a tendency to think all materials used by various MFRs are created equally. Not necessarily so.
__________________
dznf0g is offline   Reply With Quote
Old 12-08-2010, 10:06 AM   #6
Be Calm, Have a Cupcake
 
Secguru's Avatar
 
Vintage Kin Owner
Houston , Texas
Join Date: Nov 2007
Posts: 223
Images: 1
Quick Question about WD Hitches and 3/4 Ton Trucks

Andy,

This may be the world's most stupid question but here goes... (See end quote for hilarity regarding me.)

It is my understanding that as Airstreams require a soft suspension to maintain their body integrity, and a 3/4 to 1 Ton truck needs a payload to achieve that, then are WD Hitches even needed on those trucks if their beds are otherwise empty?

If a 34' exerts 1000 lbs of tongue weight, and the payload on a 3/4 ton truck is 1500 lbs, would the combination work well without a WD hitch as the tongue weight of the Airstream would put the rear suspension of the truck right where it should be for a soft ride?
__________________
Secguru

Would you rather have a mansion full of money or a trailer full of love?
Secguru is offline   Reply With Quote
Old 12-08-2010, 10:28 AM   #7
Rivet Master
 
dznf0g's Avatar

 
2007 30' Classic
Oswego , Illinois
Join Date: Jul 2010
Posts: 9,401
Images: 5
Andy,

Will you be using various trucks and repeat the tests? I suspect the delfection of the bars at a given weight will be very different between a half, 3/4, and 1 ton rear suspension.
__________________
dznf0g is offline   Reply With Quote
Old 12-08-2010, 10:57 AM   #8
Rivet Master
 
dznf0g's Avatar

 
2007 30' Classic
Oswego , Illinois
Join Date: Jul 2010
Posts: 9,401
Images: 5
Quote:
Originally Posted by Secguru View Post
Andy,

This may be the world's most stupid question but here goes... (See end quote for hilarity regarding me.)

It is my understanding that as Airstreams require a soft suspension to maintain their body integrity, and a 3/4 to 1 Ton truck needs a payload to achieve that, then are WD Hitches even needed on those trucks if their beds are otherwise empty?

If a 34' exerts 1000 lbs of tongue weight, and the payload on a 3/4 ton truck is 1500 lbs, would the combination work well without a WD hitch as the tongue weight of the Airstream would put the rear suspension of the truck right where it should be for a soft ride?
Secguru,

I know you addressed to Andy, but here goes. There are MANY posts relative to these questions. Some with fairly heated discussions. Search on key words like hitch, tongue weight, etc. for all the reding you can stand!

You question on payload is :loaded" for so many reasons. Among them is spring rates of various truck manufacturers, proper load distribution (not lod on the rear suspension alone....etc.)

Also, I am aware of no 1/2 ton which has a payload of 1000#s, nor a 3/4 ton at 1500#s, nor a one ton at 2000#s.

This nomenclature is decades old when the ratings and names were accurte. Today most 1/2 tons payload is over 3/4 ton....a 3/4 ton is over one ton....and a one ton is well over 3000# (dependant upon single rear wheel and dually).

Add to that various manufcturers view on progressive spring rates and auxillary springs and you have a never ending discussion.

Remember, WD hitches are meant to distribute weight to achieve proper handling of the trailer/TV combination. There are many fine points to this discussion/argument....but they are well covered elsewhere.
__________________
dznf0g is offline   Reply With Quote
Old 12-08-2010, 10:59 AM   #9
Rivet Master
 
dznf0g's Avatar

 
2007 30' Classic
Oswego , Illinois
Join Date: Jul 2010
Posts: 9,401
Images: 5
I gota get a new keyboard!!!!! My most commonly used vowels don't "wk s wll", sorry.
__________________
dznf0g is offline   Reply With Quote
Old 12-08-2010, 11:16 AM   #10
Rivet Master
 
dznf0g's Avatar

 
2007 30' Classic
Oswego , Illinois
Join Date: Jul 2010
Posts: 9,401
Images: 5
SEC,
Just looked it up for a Silverado, just as an example:
Max payload:
"1/2 ton" 1980#
"3/4 ton" 4192#
"1 ton" 6635#
__________________
dznf0g is offline   Reply With Quote
Old 12-08-2010, 11:36 AM   #11
Rivet Master
 
SteveH's Avatar
 
2005 39' Land Yacht 390 XL 396
Common Sense , Texas
Join Date: Sep 2007
Posts: 5,311
Oh Boy! Wait, let me make some popcorn.
__________________
Regards,
Steve
SteveH is offline   Reply With Quote
Old 12-08-2010, 11:43 AM   #12
Rivet Master
Airstream Dealer
 
Inland RV Center, In's Avatar
 
Corona , California
Join Date: Feb 2002
Posts: 16,499
Images: 1
Quote:
Originally Posted by SteveH View Post
Oh Boy! Wait, let me make some popcorn.
You will need it.

So far, up until now, interested owners have posted.

I had a very hard time waiting for more negativity.

Andy
__________________
Inland RV Center, In is offline   Reply With Quote
Old 12-08-2010, 11:44 AM   #13
Rivet Master
 
dznf0g's Avatar

 
2007 30' Classic
Oswego , Illinois
Join Date: Jul 2010
Posts: 9,401
Images: 5
Quote:
Originally Posted by SteveH View Post
Oh Boy! Wait, let me make some popcorn.
Don't need to go there....that's for another thread...an existing one.

More on topic....Andy, will you share you test perameters and accept input, for what it's worth? (that'll open a can, won't it?)

I am thrilled you're taking the initiative to take this on, so we all have some factual data. Kudos!
__________________
dznf0g is offline   Reply With Quote
Old 12-08-2010, 11:45 AM   #14
4 Rivet Member
 
1973 31' Excella 500
Spring Green , Wisconsin
Join Date: Aug 2010
Posts: 265
Quote:
Originally Posted by Secguru View Post
Andy,

This may be the world's most stupid question but here goes... (See end quote for hilarity regarding me.)

It is my understanding that as Airstreams require a soft suspension to maintain their body integrity, and a 3/4 to 1 Ton truck needs a payload to achieve that, then are WD Hitches even needed on those trucks if their beds are otherwise empty?

If a 34' exerts 1000 lbs of tongue weight, and the payload on a 3/4 ton truck is 1500 lbs, would the combination work well without a WD hitch as the tongue weight of the Airstream would put the rear suspension of the truck right where it should be for a soft ride?
I have towed my 31' AS three times for a total distance of less than 200 miles with my Ram 1500. I can tell you that with a tongue weight of about 800#, the load on the hitch definitely lowers the rear of the TV and takes load off of the front wheels (of the TV) with nothing in the bed of the truck. There is an effect on the handling although I've not had any significant problems. But, when her first trip is made in the spring, she will be equipped with a WD hitch.

The rated loads for pickups assume the load will be distributed within the cargo area, above or between the axles, which is a lot different than hanging it all on a hitch that is between 2 and 3 feet behind the rear axle of the truck. There is a significant difference in the load capacity and the allowable hitch weight for any pickup. (and it may even be so stated in the owner's manual of the pickup)
__________________

__________________
Lew TAC #WI-6
Nobody can help everybody, but everybody can help somebody.
driftless 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
Load distribution hitches-an analysis nickcrowhurst Hitches, Couplers & Balls 92 03-15-2010 07:41 PM
Blue OX hitches load levelers? Resorts Hitches, Couplers & Balls 4 07-16-2007 09:09 PM
Looking for photo/ad of equalizing hitch bkahler Off Topic Forum 4 08-20-2006 09:52 PM
Load sensing suspension and Equalizing hitch. 59toaster Hitches, Couplers & Balls 5 07-31-2005 03:01 PM
Equalizing hitch amymarie LP Gas, Piping, Tanks & Regulators 3 01-07-2005 01:28 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:12 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.