I do a "pre trip inspection" everytime that we are packing for a weekend. Because of the issues that some have had with the Andersen hitch and different couplers, I make sure to check the coupler just to look for anything out of the ordinary.
2004 F150 FX4, with lots of mods and way too much money dumped into the truck for said mods
2013 Passport 3220BH
old TTs:
2012 Grey Wolf 26BH
2001 Kodiak K215
PHS79 wrote:
Our TT has the 81911 and we have the Andersen hitch last year we put on only about 2000 miles. If we still have the TT and the couple would have to be replaced at some point down the road, I would install a Bulldog hitch. We have Bulldog couplers on numerous trailers, one of which has more than 100,000 miles on it and still has the original coupler.
I do a "pre trip inspection" everytime that we are packing for a weekend. Because of the issues that some have had with the Andersen hitch and different couplers, I make sure to check the coupler just to look for anything out of the ordinary.
Our TT has the 81911 and we have the Andersen hitch last year we put on only about 2000 miles. If we still have the TT and the couple would have to be replaced at some point down the road, I would install a Bulldog hitch. We have Bulldog couplers on numerous trailers, one of which has more than 100,000 miles on it and still has the original coupler.
I do a "pre trip inspection" everytime that we are packing for a weekend. Because of the issues that some have had with the Andersen hitch and different couplers, I make sure to check the coupler just to look for anything out of the ordinary.
Checking over the coupler is a good practice no matter the brand of hitch used. I do. Been doing it long before I got an Andersen. Some couplers are pretty flimsy.
Ron Gratz wrote:
First we need to define some dimensions and variables. Let:
a = tow vehicle wheelbase
b = ball overhang (longitudinal distance from TV rear axle to ball)
c = distance from ball to mid-point between the TT's axles
d = perpendicular distance from Andersen chain to center of ball (reported by Andersen owner to be 6.5")
TW = tongue weight
LTT = load transferred to TT's axles
LF1 = load removed from TV's front axle due to TW without WD applied
LF2 = load transferred to TV's front axle when WD is activated
T = Andersen chain tension per chain
M = moment (torque) generated by Andersen chain tension (total for 2 chains)
then (assuming zero pitch-axis rotational friction between ball and coupler)
M = 2*d*T
LTT = M/c = 2*d*T/c
LF2 = LTT*(b+c)/a = 2*d*T*(b+c)/(a*c)
also
LF1 = TW*b/a
If we want to restore a load equal to some percentage (call it FALR) of that which was removed from the front axle, we have:
LF2 = LF1*FALR/100, or 2*d*T*(b+c)/(a*c) = FALR*TW*b/(a*100)
solving for chain tension (per chain) gives
T = FALR*TW*b*c/{2*d*(b+c)*100}
for example, if: b=60", c=200", d=6.5", TW=600#, and you want to restore 50% of the load removed (FALR=50)
T = 50*600*60*200/(2*6.5*260*100) = 1065# per chain
Ron
JBarca wrote:
Hi Ed, Welcome to the discussion! When you came up with 1,000# per chain load, what are the assumptions surrounding this?
John, I don't know how Ed did it, but here is my approach to defining the relationship between tension and load transfer.Hi Ed, Welcome to the discussion! When you came up with 1,000# per chain load, what are the assumptions surrounding this?
First we need to define some dimensions and variables. Let:
a = tow vehicle wheelbase
b = ball overhang (longitudinal distance from TV rear axle to ball)
c = distance from ball to mid-point between the TT's axles
d = perpendicular distance from Andersen chain to center of ball (reported by Andersen owner to be 6.5")
TW = tongue weight
LTT = load transferred to TT's axles
LF1 = load removed from TV's front axle due to TW without WD applied
LF2 = load transferred to TV's front axle when WD is activated
T = Andersen chain tension per chain
M = moment (torque) generated by Andersen chain tension (total for 2 chains)
then (assuming zero pitch-axis rotational friction between ball and coupler)
M = 2*d*T
LTT = M/c = 2*d*T/c
LF2 = LTT*(b+c)/a = 2*d*T*(b+c)/(a*c)
also
LF1 = TW*b/a
If we want to restore a load equal to some percentage (call it FALR) of that which was removed from the front axle, we have:
LF2 = LF1*FALR/100, or 2*d*T*(b+c)/(a*c) = FALR*TW*b/(a*100)
solving for chain tension (per chain) gives
T = FALR*TW*b*c/{2*d*(b+c)*100}
for example, if: b=60", c=200", d=6.5", TW=600#, and you want to restore 50% of the load removed (FALR=50)
T = 50*600*60*200/(2*6.5*260*100) = 1065# per chain
Ron
Now this calculation makes me smile - it has been many years since my Statics and Dynamics classes! I especially like it because it shows my main assumption might actually be correct. But I will disclose how I came up with the 1,000# per chain estimate: several posts discussed a similar setup as mine that had various real measurements that showed about 1,000# per chain transferring the correct amount of weight to the front axle.
Ron's comment about the safety spec requiring that force for only 5 seconds is very relevant new information for me.
So a simple comparison (using rough estimate numbers - not exact) might be like this:
8 hours = 28,800 seconds. Let's round up to 30,000 seconds for a long day of driving.
And I have a 14,000# rated coupler.
Safety spec requires 3X the coupler rating for 5 seconds:
42,000# force for 5 seconds required by safety spec.
Andersen WDH exerts a constant baseline force:
2,000# force for 30,000 seconds
(Caution: THIS 2,000# force number will vary significantly for each rig)
Traditional WDH exerts a constant baseline force closer to zero.
Both couplers experience lots of dynamic forces from road use in all directions on top of the baseline (static) force.
So the obvious difference (as everyone following this thread knows and I am catching up on) is the Andersen WDH has a constant baseline force applied to the coupler in a rear direction.
And the baseline force on the coupler will vary significantly per rig depending on how much force is needed to get proper weight distribution.
And one coupler type (Atwood 88xxx series) so far has been shown to not like that constant baseline force.
Very enlightening.
And my 1,000 lbs per chain assumption is quite different from John's calculations that show almost 3,000 lbs. per chain for his 1,400# tongue weight setup. John's calculations.
I guess for now the bottom line for me is the more you have to compress the urethane bushing for proper weight distribution the more baseline force you are putting on the coupler. Know your coupler and keep an eye on it.
I just went outside, laid down on the gravel and looked "up" at the inside of my coupler for the first time. (Sunday morning in my pajamas
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
)What a great forum.
Ed
eb145 wrote:
Snip...
I just went outside, laid down on the gravel and looked "up" at the inside of my coupler for the first time. (Sunday morning in my pajamas )
What a great forum.
Ed
Snip...
I just went outside, laid down on the gravel and looked "up" at the inside of my coupler for the first time. (Sunday morning in my pajamas
)What a great forum.
Ed
Pictures!!!! We need pictures!
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/biggrin.gif "biggrin")
Barney
2004 Sunnybrook Titan 30FKS TT
Hensley "Arrow" 1400# hitch (Sold)
Not towing now.
Former tow vehicles were 2016 Ram 2500 CTD, 2002 Ford F250, 7.3 PSD, 1997 Ram 2500 5.9 gas engine
eb145 wrote:
Now this calculation makes me smile - it has been many years since my Statics and Dynamics classes! I especially like it because it shows my main assumption might actually be correct. But I will disclose how I came up with the 1,000# per chain estimate: several posts discussed a similar setup as mine that had various real measurements that showed about 1,000# per chain transferring the correct amount of weight to the front axle.
Ron's comment about the safety spec requiring that force for only 5 seconds is very relevant new information for me.
So a simple comparison (using rough estimate numbers - not exact) might be like this:
8 hours = 28,800 seconds. Let's round up to 30,000 seconds for a long day of driving.
And I have a 14,000# rated coupler.
Safety spec requires 3X the coupler rating for 5 seconds:
42,000# force for 5 seconds required by safety spec.
Andersen WDH exerts a constant baseline force:
2,000# force for 30,000 seconds
(Caution: THIS 2,000# force number will vary significantly for each rig)
Traditional WDH exerts a constant baseline force closer to zero.
Both couplers experience lots of dynamic forces from road use in all directions on top of the baseline (static) force.
So the obvious difference (as everyone following this thread knows and I am catching up on) is the Andersen WDH has a constant baseline force applied to the coupler in a rear direction.
And the baseline force on the coupler will vary significantly per rig depending on how much force is needed to get proper weight distribution.
And one coupler type (Atwood 88xxx series) so far has been shown to not like that constant baseline force.
Very enlightening.
And my 1,000 lbs per chain assumption is quite different from John's calculations that show almost 3,000 lbs. per chain for his 1,400# tongue weight setup. John's calculations.
I guess for now the bottom line for me is the more you have to compress the urethane bushing for proper weight distribution the more baseline force you are putting on the coupler. Know your coupler and keep an eye on it.
I just went outside, laid down on the gravel and looked "up" at the inside of my coupler for the first time. (Sunday morning in my pajamas )
What a great forum.
Ed
Ron Gratz wrote:
First we need to define some dimensions and variables. Let:
a = tow vehicle wheelbase
b = ball overhang (longitudinal distance from TV rear axle to ball)
c = distance from ball to mid-point between the TT's axles
d = perpendicular distance from Andersen chain to center of ball (reported by Andersen owner to be 6.5")
TW = tongue weight
LTT = load transferred to TT's axles
LF1 = load removed from TV's front axle due to TW without WD applied
LF2 = load transferred to TV's front axle when WD is activated
T = Andersen chain tension per chain
M = moment (torque) generated by Andersen chain tension (total for 2 chains)
then (assuming zero pitch-axis rotational friction between ball and coupler)
M = 2*d*T
LTT = M/c = 2*d*T/c
LF2 = LTT*(b+c)/a = 2*d*T*(b+c)/(a*c)
also
LF1 = TW*b/a
If we want to restore a load equal to some percentage (call it FALR) of that which was removed from the front axle, we have:
LF2 = LF1*FALR/100, or 2*d*T*(b+c)/(a*c) = FALR*TW*b/(a*100)
solving for chain tension (per chain) gives
T = FALR*TW*b*c/{2*d*(b+c)*100}
for example, if: b=60", c=200", d=6.5", TW=600#, and you want to restore 50% of the load removed (FALR=50)
T = 50*600*60*200/(2*6.5*260*100) = 1065# per chain
Ron
JBarca wrote:
Hi Ed, Welcome to the discussion! When you came up with 1,000# per chain load, what are the assumptions surrounding this?
John, I don't know how Ed did it, but here is my approach to defining the relationship between tension and load transfer.Hi Ed, Welcome to the discussion! When you came up with 1,000# per chain load, what are the assumptions surrounding this?
First we need to define some dimensions and variables. Let:
a = tow vehicle wheelbase
b = ball overhang (longitudinal distance from TV rear axle to ball)
c = distance from ball to mid-point between the TT's axles
d = perpendicular distance from Andersen chain to center of ball (reported by Andersen owner to be 6.5")
TW = tongue weight
LTT = load transferred to TT's axles
LF1 = load removed from TV's front axle due to TW without WD applied
LF2 = load transferred to TV's front axle when WD is activated
T = Andersen chain tension per chain
M = moment (torque) generated by Andersen chain tension (total for 2 chains)
then (assuming zero pitch-axis rotational friction between ball and coupler)
M = 2*d*T
LTT = M/c = 2*d*T/c
LF2 = LTT*(b+c)/a = 2*d*T*(b+c)/(a*c)
also
LF1 = TW*b/a
If we want to restore a load equal to some percentage (call it FALR) of that which was removed from the front axle, we have:
LF2 = LF1*FALR/100, or 2*d*T*(b+c)/(a*c) = FALR*TW*b/(a*100)
solving for chain tension (per chain) gives
T = FALR*TW*b*c/{2*d*(b+c)*100}
for example, if: b=60", c=200", d=6.5", TW=600#, and you want to restore 50% of the load removed (FALR=50)
T = 50*600*60*200/(2*6.5*260*100) = 1065# per chain
Ron
Now this calculation makes me smile - it has been many years since my Statics and Dynamics classes! I especially like it because it shows my main assumption might actually be correct. But I will disclose how I came up with the 1,000# per chain estimate: several posts discussed a similar setup as mine that had various real measurements that showed about 1,000# per chain transferring the correct amount of weight to the front axle.
Ron's comment about the safety spec requiring that force for only 5 seconds is very relevant new information for me.
So a simple comparison (using rough estimate numbers - not exact) might be like this:
8 hours = 28,800 seconds. Let's round up to 30,000 seconds for a long day of driving.
And I have a 14,000# rated coupler.
Safety spec requires 3X the coupler rating for 5 seconds:
42,000# force for 5 seconds required by safety spec.
Andersen WDH exerts a constant baseline force:
2,000# force for 30,000 seconds
(Caution: THIS 2,000# force number will vary significantly for each rig)
Traditional WDH exerts a constant baseline force closer to zero.
Both couplers experience lots of dynamic forces from road use in all directions on top of the baseline (static) force.
So the obvious difference (as everyone following this thread knows and I am catching up on) is the Andersen WDH has a constant baseline force applied to the coupler in a rear direction.
And the baseline force on the coupler will vary significantly per rig depending on how much force is needed to get proper weight distribution.
And one coupler type (Atwood 88xxx series) so far has been shown to not like that constant baseline force.
Very enlightening.
And my 1,000 lbs per chain assumption is quite different from John's calculations that show almost 3,000 lbs. per chain for his 1,400# tongue weight setup. John's calculations.
I guess for now the bottom line for me is the more you have to compress the urethane bushing for proper weight distribution the more baseline force you are putting on the coupler. Know your coupler and keep an eye on it.
I just went outside, laid down on the gravel and looked "up" at the inside of my coupler for the first time. (Sunday morning in my pajamas
)What a great forum.
Ed
What did you see? Are you using an Andersen hitch and looking for damage? Pictures would be great if you are.
And I had no idea of what kind of coupler I have on my trailer.
I now know it is a Redline CA5400 coupler. And NOT the Atwood 88xxx series coupler.
![[image]](http://www.etrailer.com/Merchant2/graphics/00000001/pics/C/A/CA5400_tn.jpg)
I even found a little video for it:
Redline CA5400 trailer coupler at ETrailer.com
Ed
eb145 wrote:
I am thinking about getting an Andersen WDH.
And I had no idea of what kind of coupler I have on my trailer.
I now know it is a Redline CA5400 coupler. And NOT the Atwood 88xxx series coupler.
I even found a little video for it:
Redline CA5400 trailer coupler at ETrailer.com
Ed
I am thinking about getting an Andersen WDH.
And I had no idea of what kind of coupler I have on my trailer.
I now know it is a Redline CA5400 coupler. And NOT the Atwood 88xxx series coupler.
I even found a little video for it:
Redline CA5400 trailer coupler at ETrailer.com
Ed
I believe you'll want to examine some of the AIR posts to see the differences between the two ATWOOD coupler types. Just a different brand may not be enough, it would be the design of things.
Another recent post over there by a contributor who got fed up with lack of FALR and replaced the ANDERSON with a PRO PRIDE found that the ANDERSON bracket mount fastener holes to the TT frame had elongated in the approximately 4k miles (IIRC) of towing his mid-sized AIRSTREAM.
.
1990 35' SILVER STREAK Sterling, 9k GVWR
2004 DODGE RAM 2WD 305/555 ISB, QC SRW LB NV-5600, 9k GVWR
Hensley Arrow; 11-cpm solo, 17-cpm towing fuel cost
(if you see it) the obvious issue (crack, looseness, etc), but what about while
towing out 'there' ?
It does not surprise me that the set screw holes (or gouged indentation) has
elongated. That is how the Andersen works
Wonder about those who welded their bushing brackets onto the tongue
Since no compliance, the bushings take it all
Depends on the amount of compression and how much stroke is left before those
bushings fatigue to crack/break apart/etc
If me, I'd have many, many more bushings in series to increase the potential
stroke of the spring stack. Design the recommended compression to somewhere in
the middle of that stroke (based on expected or desired WD force vs the tongue)
Ditto that force dynamics exercise...that is what I saw and noodled when John first
posted this new to me hitch system
Still think an elegant design, but as usual...the devil is in the details and
the 'testing', which in today's product world...those test mules are us...
THANK YOU to Ron for posting that link and never saw a coupler latch like that.
Interesting and initially would seem better for the way Andersen loads coupler
latches...weird and needing more noodling. First blush says not in the bottom
area of that latch design, but upwards in how those two 'MOVING' components
interplay. Since both moves, wonder if over time, that very movement becomes the
issue?
Again for those who don't know what the or how the latch does it'w work...
The ball snugs into the front (towards the TV) of the formed coupler dome, which
has a lower hemisphere that goes below the equator
The latch then moves a pawl or some such into the back of the ball and creates
a lower hemisphere.
Now the balls equator is larger in dia than the subsequent dia of the lower
hemisphere created by that latch
Why when the ball is 'stuck', most will back up the TV into the coupler while
the latch is opened.
This moves the ball away from the front dome area and into an area that has an
opening larger than the ball's equator (circumference or dia)
Since this discussion on forces on the latch...ask you guys to noodle what might
be the forces on the latch during a whop-d-do
Assume the bushings have a very slow rate of change (why it works so well to snub
porpoising) will it compress more during that XXX milliseconds during the bottoming
of that whop-d-do?
I say or initially think, it will NOT compress very fast or fast enough to
absorb those forces and why the reported bushing bracket set screw indentation
elongation or movement
What is the force over and above the preset via torque on the bushing nut on
the bushing?
How many cycles is that bushing(s) good for at those forces?
Now that then brings into question the chain clevis that is ground down, polished
to reduce the cross section of it...how close to the plastic point of the
metal? How many cycles will it endure at those forces?
Since the chain is welded to the bushing rod, what is the condition of the
subsequent weld(s)? Did the chain lose it's temper, or was it dead soft metal
chain to begin with?
Hope there isn't any angular movement between the rod/chain and the bushing
bracket...tin canning is a potential on that now questionable weld (to me)
Note to those who are not in design, nor in CDR cycles of any design...my questions
are NOT pessimistic, but part of the design review cycle.
-Ben Picture of my rig
1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...
Mike & Tracy Boyd
2013 LaCrosse 318BHS Travel Trailer - Forest River - Prime Time
2006 Silverado 2500HD 4x4 Crewcab SB DMax/Allison
Graduated from 1999 Dodge Ram Extended 2wd 5.9L &
1996 Jayco 1208KB Popup
then from a 2005 Prowler Lynx Ultralite 29BHS
I can also say this - the people at Andersen have been very good with talking with me. It took a while to get things going back and forth but I ended up speaking with their VP for quite a while. He is a really nice guy and was very helpful and open to talking with me. He admitted to the hitches shortcoming with weight distribution. They knew they would hit a limit but said that after speaking with many hitch owners and lots of testing they decided that they were happy with the setup. When they designed it they knew they would need to compromise somewhere, almost all designs have a compromise. They were aiming for simple, lighweight, better ride with reduced bounce and keeping it clean (grease free). On all of those points they nailed it.
As for the coupler, I honestly dont know what model coupler I have on my FR. It doesnt show any abnormal wear that I can tell but it is also a brand new TT with only a handful of trips. It was a concern of mine after being brought up for long term use.
For me the Andersen will not work and I am in the process of shopping for a new WD system. For people who dont need a lot of weight moved forward or are not concerned with that I think its a very viable option to look into. I truly do wish they could have made it work on my setup, the ride when towing was near perfect.
2012 FR Surveyor Sport 295
2015 Nissan NVP 3500 SL 5.6L
Tekonsha P3 / "New" Blue Ox Sway Pro