You really didn't use the b*** word -- did you?
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Ron
JBarca wrote:
It would be interesting to see if that somewhat linear relationship he has seen from 0 to 1,200# of urethane spring force held that constant on a tongue weight of 1000 or 1,400#.
John, I think that the load/compression relationship for Bruce's springs is not dependent on tongue weight.It would be interesting to see if that somewhat linear relationship he has seen from 0 to 1,200# of urethane spring force held that constant on a tongue weight of 1000 or 1,400#.
The relationship which Bruce obtained simply says that it takes a load of about 1200# to cause 1/4" of compression.
I have no reason to question Bruce's results.
However, I do recall from the YouTube video that Ryan Andersen said 1/4" of compression would produce about 2000# of "pressure" and that both springs combined would pull the trailer forward with about 4000# of force.
So, the spring "stiffness" measured by Bruce is about one-half the value stated in the YouTube video.
Perhaps the video number is for a urethane formulation which is different from that in Bruce's springs.
IMO, the urethane spring "stiffness" value measured by Bruce is consistent with his scales data and also with the scaled load transfer data provided by Renojack.
Their scales data do not appear to be consistent with a "stiffness" corresponding to a compression of 1/4" for a load of 2000#.
For comparison, with a 1000# tongue weight and a typical TV/TT combination, a WDH would need to transfer almost 500# to the TV's front axle to give 100% load restoration.
The scales data presented by Bruce and Renojack suggest their hitches would transfer about 220-240# to the front axle at 1/4" of urethane spring compression.
Of course these estimates are based on some simplifying assumptions.
For example, it is assumed that the pitch-axis torque generated by friction forces between ball and coupler is negligible.
Given the uncertainty about the coupler-ball interface, it's difficult to know if that's a reasonable assumption.
Ron
I agree with your last reply. No questions there however I may not have created enough words to explain my thoughts.
When I started looking at the Andersen I was trying to apply it to my TV and TT. From this reply I came up with this.
John wrote:
In my case I have an actual 1,400# TW and this hitch is rated that high. That is approx. 1,100 # at each snap up chain using 28.5” long WD bar or 5,225 ft. lb of torque into the receiver. The Anderson using it’s 8” tow ball would need 7,838# total chain force to create this.
There is some error in this as my Reese Tow beast shank is longer then the Anderson shank but it get’s me in the league of feeling what chain forces are going on with the Anderson.
In my case I have an actual 1,400# TW and this hitch is rated that high. That is approx. 1,100 # at each snap up chain using 28.5” long WD bar or 5,225 ft. lb of torque into the receiver. The Anderson using it’s 8” tow ball would need 7,838# total chain force to create this.
There is some error in this as my Reese Tow beast shank is longer then the Anderson shank but it get’s me in the league of feeling what chain forces are going on with the Anderson.
And then
Ron wrote:
For comparison, with a 1000# tongue weight and a typical TV/TT combination, a WDH would need to transfer almost 500# to the TV's front axle to give 100% load restoration.
The scales data presented by Bruce and Renojack suggest their hitches would transfer about 220-240# to the front axle at 1/4" of urethane spring compression.
For comparison, with a 1000# tongue weight and a typical TV/TT combination, a WDH would need to transfer almost 500# to the TV's front axle to give 100% load restoration.
The scales data presented by Bruce and Renojack suggest their hitches would transfer about 220-240# to the front axle at 1/4" of urethane spring compression.
I agree and I am not questioning this. The question comes down to can the Andersen hitch create 7,800# of force in each chain used on my setup for a 1,400# TW and how much compression will that be? Is the urethane so compressed that that very small changes in compression of the urethane greatly affect the WD? It may not be as smooth as Bruce's data for load verses compression when at the other end of the force range.
From Bruce's post on the other forum
Bruce wrote:
I now better understand why only 1/16" compression works for my rig, as it is putting a total of 500-600 pounds of weight distributing force on the hitch. Increasing the compression to 3/32" increases the total force to about 900 pounds, which seems to be too much for my Honda.
I now better understand why only 1/16" compression works for my rig, as it is putting a total of 500-600 pounds of weight distributing force on the hitch. Increasing the compression to 3/32" increases the total force to about 900 pounds, which seems to be too much for my Honda.
If I use Bruce's data where he used a force gage in the chain, 1/16" = 600# of chain force. If this is a linear relationship which I doubt it is, for 7,800# chain force it would need to compress 13/16" EDIT: 6-10-12 I miss-read Bruce's note. The 500 to 600# is combined both chains. The compression required will be more. See reply 2 notes down.
I have my doubts that will happen with the size of wrenches we are talking about here. This may also come down to that Andersen has a totally different thought process on what is good WD. They show a F250 in their video. They may allow the truck to take bear more of the TW on the rear axle and let the front go light.
I will have to find which poster stated he could not pull any harder on the wrench to get more WD.
Thanks
John
* This post was edited 06/10/12 11:24am by JBarca *
John & Cindy
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10
CC, SB, Lariat & FX4 package
21,000 GCWR, 11,000 GVWR
Ford Tow Command
1,700# Reese HP hitch & HP Dual Cam
2 1/2" Towbeast Receiver
2004 Sunline Solaris T310SR
(I wish we were camping!)
JBarca wrote:
---The question comes down to can the Andersen hitch create 7,800# of force in each chain used on my setup for a 1,400# TW and how much compression will that be?---
John, the answer depends on how much the urethane spring can be compressed and how the "spring rate" changes beyond 1/4" of compression. We don't have that information for the Andersen WD springs.---The question comes down to can the Andersen hitch create 7,800# of force in each chain used on my setup for a 1,400# TW and how much compression will that be?---
Quote:
Is the urethane so compressed that that very small changes in compression of the urethane greatly affect the WD? It may not be as smooth as Bruce's data for load verses compression when at the other end of the force range.
Again, we don't know the spring properties beyond the 1/4" compression measured by Bruce. This webpage shows urethane spring load-deflection curves for deflections up to 0.8". But, no plot shows loads up to 1200#. Is the urethane so compressed that that very small changes in compression of the urethane greatly affect the WD? It may not be as smooth as Bruce's data for load verses compression when at the other end of the force range.
Quote:
If I use Bruce's data where he used a force gage in the chain, 1/16" = 600# of chain force. If this is a linear relationship which I doubt it is, for 7,800# chain force it would need to compress 13/16"
Bruce's data showed a load of 260# per chain required for a compression of 1/16". Again, we don't know what happens beyond 1/4". If I use Bruce's data where he used a force gage in the chain, 1/16" = 600# of chain force. If this is a linear relationship which I doubt it is, for 7,800# chain force it would need to compress 13/16"
Quote:
I have my doubts that will happen with the size of wrenches we are talking about here. This may also come down to that Andersen has a totally different thought process on what is good WD. They show a F250 in their video. They may allow the truck to take bear more of the TW on the rear axle and let the front go light.
I will have to find which poster stated he could not pull any harder on the wrench to get more WD.
In this post, Renojack indicated the maximum compression he could achieve was a little over 3/8".I have my doubts that will happen with the size of wrenches we are talking about here. This may also come down to that Andersen has a totally different thought process on what is good WD. They show a F250 in their video. They may allow the truck to take bear more of the TW on the rear axle and let the front go light.
I will have to find which poster stated he could not pull any harder on the wrench to get more WD.
Ron
Ron Gratz wrote:
Ron
Quote:
If I use Bruce's data where he used a force gage in the chain, 1/16" = 600# of chain force. If this is a linear relationship which I doubt it is, for 7,800# chain force it would need to compress 13/16"
Bruce's data showed a load of 260# per chain required for a compression of 1/16". Again, we don't know what happens beyond 1/4". If I use Bruce's data where he used a force gage in the chain, 1/16" = 600# of chain force. If this is a linear relationship which I doubt it is, for 7,800# chain force it would need to compress 13/16"
Quote:
I have my doubts that will happen with the size of wrenches we are talking about here. This may also come down to that Andersen has a totally different thought process on what is good WD. They show a F250 in their video. They may allow the truck to take bear more of the TW on the rear axle and let the front go light.
I will have to find which poster stated he could not pull any harder on the wrench to get more WD.
In this post, Renojack indicated the maximum compression he could achieve was a little over 3/8".I have my doubts that will happen with the size of wrenches we are talking about here. This may also come down to that Andersen has a totally different thought process on what is good WD. They show a F250 in their video. They may allow the truck to take bear more of the TW on the rear axle and let the front go light.
I will have to find which poster stated he could not pull any harder on the wrench to get more WD.
Ron
Ron,
Your right, I miss read Bruce's data. his 500 to 600# at 1/16" was a combined load statement. Looking at his graph I see the 1/16 = 260#
This makes the situation worse.
Using 0.0625 is to 260# as 7,800# is to X, I get 1.875 inch compression.
Using Bruce's data.
Using 0.250 is to 1,220# as 7,800# is to X, I get 1.598 inch compression.
I have my reservations if one can approach that amount of compression.
And yes, Renojack is the one with the 2500 Burb I was looking for. Thanks. His truck is very similar to my older one. However his truck is a lot lighter from some reason. He reported he could not crank with the wrenches he had or even with a deeper socket much past 3/8" and still came up 260# light on the front of the Suburban with a 960# TW. Knowing the 2500 Suburban, the truck is compensating for the issue with not being able to transfer the weight. On my 2003, 2500 Burb I had a 1,200# TW verses his 960#. Not being able to move the rear axle weight would of put me over the 8,600# GVWR of the truck. On a 1,200# TW I needed to move rear axle weight to the TT to stay under the GVWR. And have a very light front end may not be desirable.
Hopefully we will get more good reports from the scales on weight transfer with the heavier TW campers or better yet, a urethane spring rat they are using.
Thanks
John
JBarca wrote:
Using 0.0625 is to 260# as 7,800# is to X, I get 1.875 inch compression.
Using Bruce's data.
Using 0.250 is to 1,220# as 7,800# is to X, I get 1.598 inch compression.
I have my reservations if one can approach that amount of compression.
I agree.Using 0.0625 is to 260# as 7,800# is to X, I get 1.875 inch compression.
Using Bruce's data.
Using 0.250 is to 1,220# as 7,800# is to X, I get 1.598 inch compression.
I have my reservations if one can approach that amount of compression.
The Andersen video says, "We like to compress it about a quarter of an inch".
In an extreme application, you might achieve a compression of 25% of unloaded length (3*0.25 = 0.75" in this case).
So far, we've not seen anything from Andersen about going more than 1/4".
Quote:
---Knowing the 2500 Suburban, the truck is compensating for the issue with not being able to transfer the weight.---
I don't know what you mean by this -- but I would like to avoid more of the "receiver consumes WD torque" discussion. ---Knowing the 2500 Suburban, the truck is compensating for the issue with not being able to transfer the weight.---
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The spring compression and front-end load transfer reported by Renojack were consistent with the compression and transfer reported by Bruce H.
Ron
I still have no returns from two emails to Andersen re: max spring compression.
RENOJACK
"The journey IS the destination"
2014 Denali 287RE TT
NV Plate "THETRLR"
2016 Ram 2500 Laramie Cummins 6.7
NV Plate "THE RAM"
Equalizer 1400#
My Andersen arrives tomorrow. I am not worried about max compression as I have a fairly light TW, but I would like to see a compression chart from them.
2012 FR Surveyor Sport 295
2015 Nissan NVP 3500 SL 5.6L
Tekonsha P3 / "New" Blue Ox Sway Pro
Your load transfer measurements are being discussed on AIR Forums beginning with this post. Thought you might be interested.
Renojack,
One of the AIR Forums members (post 163) adjusts his WDH by using the tongue jack to remove load from a chain and then turns the adjusting nut by hand.
Have you tried that approach to get more compression of the urethane springs.
Do the instructions say anything about using this approach versus using the wrench to load the springs?
This member (post 163) assumes that you have installed your brackets at the wrong location -- implying that might be the reason you cannot get sufficient load transfer.
Ron