A few WDH use questions

I'm about a year (which for me is 4-5 camping trips) into trailer towing and use of a weight-distributing hitch (WDH).  I've noticed a few things with my hitch usage that I'm not sure about.

First off, my WDH is an older model that came with my Suburban when I bought it.  I do not have a manual for it.  The vehicle hitch receiver is a Reese but the rest of the WDH parts may be Curt.  It's the style with "round" spring bars with an L-shape... I replaced the bars & retainer pins this year with Curt parts that fit perfectly, but I think this design was the same between Reese/Curt/Draw-Tite for some years.

(1) How do I know how many chain links to tension up?  I've always just picked the number that is somewhat difficult to tighten but can still be done by hand, with a pipe extension assistance.  I figure more weight distribution is better than less, with my fairly heavy tongue weight percentage around 14%.

I've taken axle weights with & without the WDH engaged, front axle weighing 2760# (WDH engaged) and 2520# (not engaged).  So it's a matter of ~240# which is not a huge percentage of overall.

(2) The left/driver side spring bar is always considerably more difficult to tension, using the same number of chain links as the right/passenger side. 

I've never weighed my trailer side-to-side but the left side (in front of the axles) is probably heavier than the right, because of the living room slide with a heavy sleeper sofa.  The right side has all the kitchen appliances, but the rear bunkhouse slide is behind the axle.  Would that have a significant effect on chain tension?

(3) What impact does the forward angle of the hitch head have on overall towing performance?  Right now I have all the vertical washers in place, slightly tilting the head OUT from the rear bumper.

(4) Sometimes on bumpy/hilly roads while towing, the front end of my Suburban will bounce up and down kinda slowly (perhaps referred to as "bucking") as the trailer tongue is also reacting to bumps.  Not as if I'll lose steering control, but it's pretty noticeable.  Does that suggest I need more weight distributed to the front axle, or is that kind of performance to be expected?

Info/experience/advice is much appreciated!

Q3- the more rearward tilt of the ball, the more it loads the front axle.

Q2- Are the snap-up brackets exactly the same distance from the center of the ball coupler on the trailer frame?

Q1- The amount of chain links depends on your set-up. There is usually a minimum number of links that the manufacturer recommends between the spring bar and the snap-up bracket connection. Most manufacturers say the spring bars should be parrallel with the trailer frame. The way weight distribution systems used to be set up was to measure the front and rear wheelwells and adjust the hitch to settle all four corners the same. IE the rear wheelwells drop 1", so you want the front to drop 1". SAE engineers, tow vehicle manufacturers, and the hitch manufacturers all have decided that is not the best way to adjust a hitch. Now they are saying to not put any extra weight on the front axle when hitched up then there was before hitching. Ford, and some 1/2 ton GM's are recommending loading the front to half of the unhitched height and the hitched height without the spring bars. For example the front wheelwells are 36" unhitched, then 40" hitched without spring bars attached, then you should shoot for about 38" for 50% FALR (front axle load return), on up to bringing it back to 36" for 100% FALR, but not lower than the original 36". Going by their directions, you are transferring way too much to the front axle. They have determined overloading the front axle can cause severe bumpsteer and possibly lead into an accident. Above all, never have the ball pulled up higher when hitched with the spring bars, than when unhitched from the trailer.
Also, when snapping up your bars, are you raising up the back of the truck with the tongue jack on the trailer? If not, that will help immensely to ease the snap-up.

kdbgoat said:

Q3- the more rearward tilt of the ball, the more it loads the front axle.

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By "rearward" do you mean angled toward the tow vehicle bumper, or away from it?  Terminology can be confusing (for a guy like me ) since the hitch is already facing backwards.  Would I change that angle only to increase or decrease FAWR as needed, if I can't do it by adjusting chain links?

kdbgoat said:

Q2- Are the snap-up brackets exactly the same distance from the center of the ball coupler on the trailer frame?

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Yes.  I just went out and measured... 28.5" in both directions.

kdbgoat said:

Also, when snapping up your bars, are you raising up the back of the truck with the tongue jack on the trailer? If not, that will help immensely to ease the snap-up.

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Yes, I do that.  Although I discovered recently that raising the tongue TOO high increases the difficulty of snap-up once again, since the truck hitch is being raised up (even though the trailer is no longer pushing down).

The info on FAWR is helpful too, makes sense the way you described it.  My driveway is not quite level and I've never gotten a real good indications using the wheelwell measurements.  The other day I actually scaled-weighed my Suburban's front axle (trailer attached) with & without spring bars engaged to measure loaded axle weight, and I'm going to compare that to non-towing front axle weight to see what my ratios are with this trailer/WDH setup.  I don't plan on towing anything else anytime soon, so the numbers shouldn't change.

Rearward, meaning the top of the ball toward the trailer. Adjusting the chains will do as you think, but only to a point. The ball should be adjusted initially by measuring the ball height on the truck, then measuring the ends of the springbars from the ground a certain distance specified by the hitch instructions. Try looking at the instructions for a Reese Pro round bar hitch, and that may help you out some. be aware what is online may still have the old way of adjusting the bars, instead of the new way.

I finished getting all my weights today, so here's how it plays out with my Suburban + TT combo and the WDH.  Both "vehicles" were loaded similar to a trip, except for kids in the Suburban and some food/clothing in the trailer.  Maybe a couple hundred pounds would be added, nothing too significant.

Suburban (alone):                        3040# front axle, 3630# rear axle
Suburban + TT (no WDH):            2520# front axle, 4920# rear axle
Suburban + TT (WDH engaged):  2760# front axle, 4620# rear axle

(The grain elevator scale I used measures in 20# increments with a 20#-40# margin of error.)

So hitching up the trailer takes 520# off of the Suburban's front axle, and engaging the WDH puts back 280#.  About 50% within the margin of error... just dumb luck obviously!  But I'm not inclined to change anything, if that's the recommended FAWR ratio I should have.  Plus I already have the round bar chains pretty tight and hitch head angle rearward, so I'm not sure what else I could do for the front axle.

Sounds like you're right on the money. The 20# tolerance on the scales is the same as mine at work.  That's pretty much the standard. At least that's one thing you don't have to wonder about anymore.

What about the trailer axles? It would really help to know how much they weigh to figure out tongue weight and percentage of gross trailer weight.

keymastr said:

What about the trailer axles? It would really help to know how much they weigh to figure out tongue weight and percentage of gross trailer weight.

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Yep and I've got all those weights too... just didn't post them earlier since they didn't change any of my Suburban axle calculations.  I used our forum library's article Weighing Travel and Fifth Wheel Trailers for directions.

(A) Entire combo (Suburban + TT):          15,520#
(B) Trailer minus tongue weight:              8180#
(C) Entire trailer (unhitched):                  9460#

That puts my tongue weight (C - B) at 1280#, which (divided by C) is about 13.5%.  Margin of error & past weighing puts the tongue weight up to 13.9% so it's on the higher end of the typical 10-15% ratio.