OK I think I got it. I'll go fiddle and report back. My take few days.
However I'm real cautious on trying to make this 3/4 ton Suburban have the same 2 3/16" rear high "attitude" angle when fully WD loaded. What I'm worried about is I know I'm going to have to drop the ball mount down a hole on the hitch shank to level the TT out. I may even have to drop it 2 holes if I'm going for the full 2 3/16" and then I'm getting even more worried. So the "ratio" make come to pass like 60% rear end 40% front end. But won't know until I try.
The moment arm on the hitch shank is going to get pretty hefty on the receiver with the ball mount that low. May have to comprise in the middle.
Again, I go fiddle and report back.
Thanks
John
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 where camping!)
The Reese HP hitch head (ball mount) can have 1700# bars added to it. However if you are going all Reese the 1700# hitch shank has a 2 1/2 sq. on it that has to fit into their Tow Beast. Then the 2 1/2" sq. tapers down to 2" to go into the HP ball mount. I do not know this for fact, but believe it is so as a forum buddy just went through all this and I believe I have want he said correct.
In my case my Putnam reciver will make it OK just I have to find a stamped 1700# shank that is 2" if one exists. and only if I have to go that way. Better to move stuff in TT and stay under 1200.
Welcome to the wonderful of setting up a Suburban. I have done it with 2, and it is interesting for sure. Your Suburban is similar to mine and it looks like your trailer weight is similar also, so here is what I think.
Okay, first of all, your truck (like mine) does not sit level to start with. The rear is higher than the front. You can see it just by looking at it, but your measurements confirm it.
Next, your tongue weight measurements must be off somewhere. Based on your axle weights, you should have 1200# tongue weight, not 1250#. (2600-2400+3400-2400) This makes me a bit suspicious of the accuracy of your weighing technique. It would be nice if you could weigh it at a CAT scale. I’m even more suspicious of your techniques because the front end is higher when hitched up than when not, but somehow it has gained 100#.
Your weights are close to mine, but they don’t quite make sense, which could be because of the measurements (which are also similar to mine).
It would be interesting to see if a CAT scale confirmed your readings, but if they are at least close to being correct, I would say you’ve got it tuned in as good as you’re going to get. As I think you know, I played with my setup for several hours at a nearby scale one day to get my setup dialed in the best I could, and your results are similar to mine, so I think you’re good to go.
The biggest question I would have is…how does it tow? More specifically, how’s the steering? With the measurements sort of contradicting the weight reading, I’m wondering if the steering feels “lite” or not. Mine did until I fixed it.
Also, at 1200# or 1250# tongue weight and having 1200# bars is calling it close. I would imagine there is a safety margin built into the bars, but I’d feel more comfortable with the next rating up.
I don't have a 3/4 ton TV. My current TV weighs 16 tons and I tow an Explorer. However, I do have an interest in WD hitches.
I am curious about some of your measurements. In going from "TV Empty" to "Full Tongue wgt.", you add 1000# to TV Rear. and remove 200# from TV Front. This suggests the TT tongue weight is 800# and not 1250#. Without the WD applied, it is more usual for the TV Rear to increase by around 150% of the TW and the TV Front to decrease by around 50% of the TW.
It also is curious that between "TV Empty" and "WD Engaged" the front axle load increases by 100#, but the front wheel wells are 9/16" higher. This suggests a negative spring constant for the front suspension.
Even more curious is the fact that the front and rear axles combined carry 5800# at "Full Tongue wgt." and 5900# with "WD Engaged". The WD system can only remove load from the TV. It cannot add load!
It appears that your axle weighing technique is giving erroneous values. If you measure the force required to lift only one tire off the ground, that value will be different than the actual load on that tire when it is on the ground. Also, if you try to measure the total axle load by placing the jack under the differential and raising both tires off the ground, you will change the vertical angle between TV and TT which will affect the amount of load transferred by the WD system.
I think you're going to have to find a different method for measuring axle loads.
Ron
On edit: I see I was composing when DavidG posted. We do have similar conclusions, although we do disagree on 800# versus 1200# for the indicated tongue weight. I'm sticking by my number for now.
"Even more curious is the fact that the front and rear axles combined carry 5800# at "Full Tongue wgt." and 5900# with "WD Engaged". The WD system can only remove load from the TV. It cannot add load!"
Ron,
I disagree. The WD hitch can and does add load to TV. First, they are heavier so you automatically add up to a few hundred lbs depending on the model. Next the basic theory of WD goes something like this: shift some of the weight off of the TV rear axle and add that weight to the front TV axle and the trailer axles. See the sticky on WD hitches.
I do agree that he needs to weigh on a GOOD scale. Using a jack will give elevated reading all the way around.
I'm not an expert, but I play one on the internet
"Never drive faster than your guardian angel can fly"
98 Chevy 3500 CC 4X4
Back to tent camping, and looking forward to no RV related issues. (Take that RV industry!)
skills4lou wrote: "Even more curious is the fact that the front and rear axles combined carry 5800# at "Full Tongue wgt." and 5900# with "WD Engaged". The WD system can only remove load from the TV. It cannot add load!"
Ron,
I disagree. The WD hitch can and does add load to TV. First, they are heavier so you automatically add up to a few hundred lbs depending on the model. ---
Of course the weight of the WD hitch does add load to the TV. I was talking about the incremental load added by tensioning the WD system which already was in place. The weight of the hitch was included in the "Full Tongue wgt" reading.
Quote: --- Next the basic theory of WD goes something like this: shift some of the weight off of the TV rear axle and add that weight to the front TV axle and the trailer axles. See the sticky on WD hitches.
I am somewhat familiar with the basic theory of WD and I have read all of the posts in the sticky on WD hitches. I am pleased that you feel the sticky is worth referencing. You are correct that the WD system will transfer load from the TV rear axle to the TT axles. Since that load no longer is on the TV, the load on the TV has been reduced. Tensioning the WD system can only remove load from the TV. It cannot add load to the TV unless the hitch and bars are installed upside down.
Quote: My Putnam XDR receiver is tongue rated at 1500# weight carrying and 1700# WD
A true Class V receiver has a 2 1/2 " shank like on the SuperDuty Ford pickups and the XDR is the standard 2" shank. I would not want to carry 1,500 lbs tongue weight without WD when towing a 15,000 lb TT on a 2" receiver.
I pull a 7400-8000# TT with a 2004 2500 6.0L 4.10RA Suburban. Last time I weighed, I had a tongue weight of 1105 #'s. I use 1200# bars.
My Suburban can handle the entire Tongue weight of the TT without weight distribution, but (as noted above) the receiver needs WD to handle load.
I set mine up with the goal of having a good tow; not the goal of being level,etc....but I check that anyway. I found that no matter what I did (within reason), I couldn't get the 'burb to lower front and back equally. Set mine up so that about 40% of the added weight goes to the front axle. The hitch is 1 "tooth" (perhaps 2, can't recall exactly) past true vertical. I flipped the mount over...so the "holes" go down from the bumper level.. and have the hitch head bolted to the bottom two holes.
At the above setup, the rear wheel well (under load w/WD hooked up) goes down roughly 3/4" more than the front, which goes down a good 1-1.5". TT is slightly (very slightly) nose down. This setup seems to tow well.
Would confirm suggestions by others...Use a CAT Scale to get true readings on axle weights.
CRL
Temporarily (6! years & counting)displaced Alaskan
My Other RV is a 1946 PA-12
First off, THANKS to all responding. It helps to get different opinions on this.
Now to clear up a few things as the discussions continue. I did state that that the force jack I was using was to ONLY be taken as a way to measure in my yard as I'm fiddling with this thing if I was shifting weight from empty to loaded, engaged not engaged. I CANNOT use it as the axle weights but could use it tell if I was shifting weights from empty and it has shown this. And do not add up the weights as they are not accurate for that. They only show that at that same point from empty to loaded to engaged that I have shifted load.
The jack is too tall to get under rear end so I had to use it at the tire points only. And when you jack up the truck you change the spring preload on the WD bars as the suspension lifts and the ball lifts, so again it can only be used as a reference if you are changing anything.
This was however using 800# bars, My dealer sold me these and when I learned they where out to lunch as I have a confirmed 1200 lb tongue, I upgraded to 1200 lb bars. But that's another post. Since doing this I have as well upgraded receivers and hitch shanks. AND now I have to reset the whole thing up. I have done so as the original post I started here has indicated.
The truck tows well as it is, it handles well and no steering problems noted. I'm trying to perfect the setup if I can. And when I get done fiddling with it in the yard, I will head back the certified scales to get all 4 axles weighed once again to verify what I have is sound.
What I am having a hard time trying to see how to do it, is to get this 3/4 ton Suburban to have equal squat all the way around with the way the GM suspension is. Yes I know you want the front heavier than empty so it does not bounce around and you do not want to overload any axles. No argument here.
Just this truck was made to carry weight into the rear and now I'm trying to force 1/2 that weight to the front. I'll try but may not be able to get there as is does not flex that well.
I understand why we want WD and I agree we needed it. Great device. However if someone puts a cargo load in the truck with no trailer at all, they do not have the benefit of WD. Does this mean they cannot drive around under the limits of the truck because they are not 50/50 split between the front and rear but yet the truck is level?
Like I said, keep the comments coming. I'm am open minded person and will admit when I have found the error in my ways. Have more than once and will again. And I'll try to push more weight to the front but do not know if I can get equal squat. It seems it may be a 3/4 ton Suburban thing. Lots of spring on a shorter WB length than a 2500HD crew cab.
JBarca wrote: What I am having a hard time trying to see how to do it, is to get this 3/4 ton Suburban to have equal squat all the way around with the way the GM suspension is. Yes I know you want the front heavier than empty so it does not bounce around and you do not want to overload any axles. No argument here.
I don't think you'll be able to do it, or maybe I should say that I wasn't able to do it either. I don't remember the measurements exactly, but I was able to get my truck to squat 1.5" in the rear and raise 1/2" in the front. I still have the OEM receiver, which many say has something to do with this, but I'll have to wait until I get a new receiver to confirm this for myself.
JBarca wrote: Just this truck was made to carry weight into the rear and now I'm trying to force 1/2 that weight to the front. I'll try but may not be able to get there as is does not flex that well.
This I'm sure you won't be able to achieve! Even with the XDR receiver you have, I don't see any way you'll get 600# of tongue weight to go up front. Even if you were more conservative and went with the old 1/3 1/3 1/3 rule of thumb, moving 400# up front would also prove to be difficult.
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I have done it with 2, and it is interesting for sure. Your Suburban is similar to mine and it looks like your trailer weight is similar also, so here is what I think.
years & counting)displaced Alaskan
