Jan-13-2012 05:35 PM
May-31-2012 10:28 AM
CHD Dad wrote:
Hey guys - since we obviously have some engineers on here, has the coupler/latch issue ever been figured out? I know many pages back there was talk of contacting one of the big coupler manufacturers about it but I dont recall ever seeing a followup to that post. To me that is the single biggest flaw and/or safety issue with the Andersen design. Having the latch fail either while towing or when it comes time to just disconnect would be a major issue!
May-31-2012 10:07 AM
"The amount of deflection of the GM hitch was amazing"
"The amount of deflection of the GM hitch was amazing"
May-31-2012 06:19 AM
May-31-2012 05:10 AM
Ron Gratz wrote:
John, I copied the following from the last post on Page 37.
I think it agrees with your statements above.Ron Gratz wrote:
I think we're saying the same thing -- if the WD spring force is the same, the load transfer will be the same -- regardless of receiver torsional stiffness.
I think we also agree that, if receiver torsional stiffness is sufficiently low, physical restrictions on ball mount tilt and/or lift chain length might limit WD bar force.
Just one point of clarification --JBarca wrote:If the receiver rotates 3.5 degrees, the excess rise at the end of a WD bar would be about 2.5". You would need to shorten the length of chain under tension by 2.5" to compensate for the receiver rotation. Is that essentially what you meant by "go 1.5 to 2 times the chain link less"? Yes this is correct. I did not do the exact math, I estimated from prior field observations.On a low stiffness system you may need to go 1.5 to 2 times the chain link less to get the same weight to move to the front axle. The hitch head may have rotated 3 to 4 degrees now for the same weight transfer.
Alternatively, you would need to increase the rearward tilt of the ball mount by 4-5 degrees. Or, you could use some combination of increased tilt and fewer links under tension.
Ron
May-31-2012 04:55 AM
Ron Gratz wrote:
I think we're saying the same thing -- if the WD spring force is the same, the load transfer will be the same -- regardless of receiver torsional stiffness.
I think we also agree that, if receiver torsional stiffness is sufficiently low, physical restrictions on ball mount tilt and/or lift chain length might limit WD bar force.
JBarca wrote:If the receiver rotates 3.5 degrees, the excess rise at the end of a WD bar would be about 2.5". You would need to shorten the length of chain under tension by 2.5" to compensate for the receiver rotation. Is that essentially what you meant by "go 1.5 to 2 times the chain link less"?On a low stiffness system you may need to go 1.5 to 2 times the chain link less to get the same weight to move to the front axle. The hitch head may have rotated 3 to 4 degrees now for the same weight transfer.
May-30-2012 09:15 PM
Ron Gratz wrote:JBarca wrote:Well, I thought we were in agreement. Now, I'm not sure. Perhaps it's just the words we're using to try to explain our thoughts.
Your statement about;Ron Gratz wrote:Yes it is true where 100% of the torque is going into the receiver, however it is not always being reflected at the front wheels of the TV. It is being lost in the process.---
However, 100% of the torque which is generated by the WD bars will be transmitted to the tow vehicle via the receiver. It has nowhere else to go.
First, I think we can agree the WD bars cannot generate torque as long as there is "slack" in the bar/hitch/drawbar/receiver/frame system.
As far as pure slack, (meaning excess clearance in the hitch shank to pin box for example) very little to almost no torque of significance is generated until the pure slack is taken out. Yes we agree on this.
There can also be deflection in the frame and in the mounting of the receiver. It is not slack as in clearance, it is a weaker member of the system. This is what I was referring to the lost part.
So, I suggest we focus on a system from which the "slack" has been eliminated.
IOW, if the bars are generating torque, there is no "slack" in the system.
This means 100% of the applied torque is transmitted to the TV and the loads on the front and rear axles will change in response to the applied torque.
Not trying to be nit picky but this is where the issues are coming. Not all TV receivers are created equal. Your statement about 100% of applied load being is transmitted to the front axles is a correct statement however the "amount" of load per WD adjustment can differ.
What has been seen in the field on some brand receivers is a low amount of torque transfer per amount of WD hitch adjustment. These are the problem receivers.
Not all TV receivers have the same level of torsional stiffness. WD bars can generate torque in a low torsional stiffness system however the amount of torque will be interactive with level of torsional stiffness for the amount of WD bar adjustment. And then there is the frame and joint deflection in some cases.
On a low torsional stiffness receiver the hitch head must rotate further to create the same WD bar load as opposed to a higher stiffness receiver.
On a high stiffness system when you decrease the chain links under tension (take up a link) you immediately get a large result of WD transfer to the front axle and you only rotated the head appox 2 degrees.
On a low stiffness system you may need to go 1.5 to 2 times the chain link less to get the same weight to move to the front axle. The hitch head may have rotated 3 to 4 degrees now for the same weight transfer.
Yes, granted 100% of the applied WD bar load is transferred to the front axle, however on a low torsional stiffness receiver the "amount" transfer is not much for a known hitch adjustment as compared to a higher torsional stiffness receiver.
If you run out of WD hitch adjustment trying to get the WD bar loaded enough to transfer the weight you want, the low efficiency of the receiver will not allow proper WD adjustment to occur. Again 100% of the what ever was generated went up front, it was just not enough.
This low efficiency receiver creates "an appearance" that the receiver is absorbing the WD adjustments you are making but not much is happening. Yes, in reality what little bit of torque you are creating is moving it is just not enough to do the work you want it too. Since you can only adjust the WD hitch so far, you cannot overcome the loss of inefficiency before running out of adjustment.
For example, if you apply a torque of 4000 lb-ft (CCW when viewed from driver's side) to a TV which has a 12.5' wheelbase, 320# will be added to the front axle and 320# will be removed from the rear.
I agree once you can create that torque
Laws of physics demand that the torque and force applied to the TV (in this simplified example, the applied force is zero) are exactly balanced by reactions at the axles.
IOW, 100% of the applied torque and force MUST be "reflected" in the axle reactions.
Neither torque nor force can be "lost in the process".
Again agreeWhen some folks talk about "consumed" or "eaten up" by the receiver, “I believe” they are referring to lost motion or excessive rotation in the receiver system.---If that's the case, they also should refer to the differing amount of WD bar force resulting from excessive rotation rather than stating that the same amount of WD spring force does not transfer as much load. Again agree, once the WD bar load is created for the intended WD on the front of the truck, the rear axle weight will move. A low torsional stiffness and low efficient receiver requires excess rotation to create the same WD bar loads. The hope is you did not run out of WD hitch adjustment by this point.
I agree that some folks may think that when that take up 1 link of chain to create a lot of force that they actually did create a large force. You are suppose to get a visible reaction when the receiver is stiff. When you run into a low stiffness receiver the WD bar load increase per chain link is a lot lower to what they may be use to or that they can quickly see much load movement. It appears to be absorbed by the receiver when in pure reality it is not, it just did not move much weight and the WD bar force load is a lower as a result of it.
Ron
May-30-2012 03:13 PM
BenK wrote:Ben, if you believe semantics and verbiage is the problem -- can you rephrase the following to get your point across?
Semantics, again, guys....I think violently agreeing in principle, but the verbiage is getting in the way...
BenK wrote:Or, could you please explain how having the same WD spring forces can result in different amounts of load transfer, if that really is the point you're making?
---So it DOES NOT transfer as much weight to the front axle as a traditional receiver would with the same WD spring forces
May-30-2012 11:01 AM
Ron Gratz wrote:JBarca wrote:Well, I thought we were in agreement. Now, I'm not sure. Perhaps it's just the words we're using to try to explain our thoughts.
Your statement about;Ron Gratz wrote:Yes it is true where 100% of the torque is going into the receiver, however it is not always being reflected at the front wheels of the TV. It is being lost in the process.---
However, 100% of the torque which is generated by the WD bars will be transmitted to the tow vehicle via the receiver. It has nowhere else to go.
First, I think we can agree the WD bars cannot generate torque as long as there is "slack" in the bar/hitch/drawbar/receiver/frame system.
So, I suggest we focus on a system from which the "slack" has been eliminated.
IOW, if the bars are generating torque, there is no "slack" in the system.
This means 100% of the applied torque is transmitted to the TV and the loads on the front and rear axles will change in response to the applied torque.
For example, if you apply a torque of 4000 lb-ft (CCW when viewed from driver's side) to a TV which has a 12.5' wheelbase, 320# will be added to the front axle and 320# will be removed from the rear.
Laws of physics demand that the torque and force applied to the TV (in this simplified example, the applied force is zero) are exactly balanced by reactions at the axles.
IOW, 100% of the applied torque and force MUST be "reflected" in the axle reactions.
Neither torque nor force can be "lost in the process".When some folks talk about "consumed" or "eaten up" by the receiver, “I believe” they are referring to lost motion or excessive rotation in the receiver system.---If that's the case, they also should refer to the differing amount of WD bar force resulting from excessive rotation rather than stating that the same amount of WD spring force does not transfer as much load.
Ron
May-29-2012 08:06 PM
JBarca wrote:Well, I thought we were in agreement. Now, I'm not sure. Perhaps it's just the words we're using to try to explain our thoughts.
Your statement about;Ron Gratz wrote:Yes it is true where 100% of the torque is going into the receiver, however it is not always being reflected at the front wheels of the TV. It is being lost in the process.---
However, 100% of the torque which is generated by the WD bars will be transmitted to the tow vehicle via the receiver. It has nowhere else to go.
When some folks talk about "consumed" or "eaten up" by the receiver, “I believe” they are referring to lost motion or excessive rotation in the receiver system.---If that's the case, they also should refer to the differing amount of WD bar force resulting from excessive rotation rather than stating that the same amount of WD spring force does not transfer as much load.
May-29-2012 04:39 PM
May-29-2012 08:57 AM
Ron Gratz wrote:
We had three days of rain here in the twin cities of Marinette, WI, and Menominee, MI.
Ron Gratz wrote:
Receiver torsional stiffness does not enter into the relationship between WD spring force and load transfer.
JBarca wrote:
---When you do reach the WD spring force to be the same on a less efficient receiver after over adjusting the hitch, then yes the WD on the TV will be the same.---
Ron Gratz wrote:
I think we're saying the same thing -- if the WD spring force is the same, the load transfer will be the same -- regardless of receiver torsional stiffness.
I think we also agree that, if receiver torsional stiffness is sufficiently low, physical restrictions on ball mount tilt and/or lift chain length might limit WD bar force.
However, 100% of the torque which is generated by the WD bars will be transmitted to the tow vehicle via the receiver. It has nowhere else to go. Nothing is "consumed" or "eaten up" by the receiver.
Ron Gratz wrote:
As a side note -- the VESC V-5 Regulation and the corresponding SAE Standard indicate that a rotation of up to 5 degrees is acceptable.
Ron
Ron Gratz wrote:
However, 100% of the torque which is generated by the WD bars will be transmitted to the tow vehicle via the receiver. It has nowhere else to go.
May-28-2012 09:22 PM
JBarca wrote:John, hope you had a good Memorial Day weekend. We had three days of rain here in the twin cities of Marinette, WI, and Menominee, MI. 😞
Dog gone... Sorry I’m late to the party. Was out camping. 🙂
Ron Gratz wrote:
Receiver torsional stiffness does not enter into the relationship between WD spring force and load transfer.
JBarca wrote:I think we're saying the same thing -- if the WD spring force is the same, the load transfer will be the same -- regardless of receiver torsional stiffness.
---When you do reach the WD spring force to be the same on a less efficient receiver after over adjusting the hitch, then yes the WD on the TV will be the same.---
May-28-2012 07:33 PM
Ron Gratz wrote:BarneyS wrote:
Ron, I learned long ago not to try to argue a point with you (:W) BUT notice that Ben said "So it DOES NOT transfer as much weight to the front axle as a traditional receiver would with the same WD spring forces." (Bold added for emphasis) I still think his point was valid.:)
If the "WD spring forces" are the same, the load transfer to the front axle will be the same
-- unless you change WD bar length, TV wheelbase, ball overhang, ball to TT axles distance, or tongue weight.
Receiver torsional stiffness does not enter into the relationship between WD spring force and load transfer.
May-26-2012 06:52 PM
May-26-2012 05:30 PM