Bowfreak wrote:
I don't think I said anything about getting my truck level.---
Sorry, I misinterpreted the last sentence of your first post.
---I was assuming the front and back would be the same offset if I had it adjusted correctly, just both a little lower due to added weight. So if the front fender was 28" and he rear fender was 30" prior to loading I was assuming that I would want the front 2" lower than the back after loading.
Thanks for the clarification. I always recommend against trying to achieve the same offset (a.k.a. "equal squat").
I believe the reason Ford, GMC/Chevrolet, Toyota, Ram, Equal-i-zer, Reese, and others have abandoned the "equal squat" approach is pretty well summed up in this
Letter to Editor by Richard H Klein, P E printed in TRAILER BODY BUILDERS Magazine. The comment which specifically addresses WDH adjustment is:
QUOTE
2. The statement “too much tongue weight can force the truck down in the back, causing the front wheels to lift to the point where steering response and braking can be severely decreased” is not the real issue with heavy tongue weights. The real problem is that the tow vehicle's yaw stability, as measured by “understeer gradient”, is severely decreased. This increases the propensity of the tow vehicle to jackknife in turning maneuvers. Specifically, recent full scale testing conducted by the SAE Tow Vehicle Trailer Rating Committee (and now published in SAE J2807), determined that the use of weight distributing hitch torque should be minimized. In fact they recommend that the Front Axle Load Restoration (FALR) not exceed 100% (100% means that the front axle weight is brought back, via weight distribution, to a weight equal to its “no trailer” condition).
UNQUOTE
A related explanation from a representative of the company which manufactures the Equal-i-zer hitch was first posted
here . It says:
QUOTE
In the past we had suggested that you should see a small drop on the front suspension. We are always trying to improve things here at Progress – our motto is “Safe and Happy Customers,” and so we are always reviewing our instructions and installation process. Recently, as part of this constant effort our engineers looked more deeply into this aspect of installation. We had always felt that a small drop was a sign that the trailer’s weight was being transferred to the front axle, and that this was essentially a good thing.
As our engineers reviewed the instructions for the last round of renewal of our instructions, the found research results that contradicted our prior thinking. There has been a substantial amount of testing conducted by experts from SAE and the RV Industry Association to find out what will produce the best stability when towing. This towing suggests that you want your front axle’s compression to be close to, but not lower than your free-standing height.
UNQUOTE
I know I am over thinking this but there is so much conflicting information out there and I haven't seen one document that tells you if you should take your measurements prior or after the TV is loaded. They all mention making the travel trailer the weight you plan on it being when loaded.
The
Equal-I-zer OWNER'S MANUAL states the following which I included in a previous post:
"
While installing or adjusting the hitch, the tow vehicle and trailer should be loaded just as they will be while traveling. This includes full propane and fresh water tanks, and any other cargo (passengers & gear) the tow vehicle or trailer will carry, including ATVs for toy haulers.
"
(Underline added for emphasis.)
To me if the end goal it to get your tow vehicle back to normal ride height ratio so it handles the same with or without the trailer then you would need to take the measurements prior.---
You previously referred to "prior or after the TV is loaded". Are you talking about all of the load (occupants, cargo, WDH, etc.) or are you talking only about load added in the bed area?
If you put 300# in the bed, how much of it would be behind the rear axle? Even if you placed all 300# with its center of gravity 2' behind rear axle, it would remove only about 50# from the front axle -- not enough to offset the weight of just one adult in the front seat.
---So if I throw 300 - 400 lbs in the bed of the truck and it sinks the rear end and raises the front end that would already cause it to handle worse before I attached the trailer to it. Which would make me think that the WDH would take the tongue weight and some of the bed load weight to help get it back to the pre loading ratio heights.
The current Tacoma Owner's Manual says:
"
If using a weight distributing hitch when towing, return the front axle to the same weight as before the trailer connection.
If front axle weight cannot be measured directly, measure the front fender height above the front axle before connection. Adjust weight distributing hitch torque until front fender is returned to the same height as before connection."
Let's assume you follow Toyota's instructions without any load in the bed and end up with the same front axle weight before and after hitching.
Then you add 300# to the bed = with 150# centered 2' ahead of the rear axle and 150# centered 2' behind the rear axle.
The added 300# will not cause any weight change on the front axle because the portion in front of the rear axle balances the portion which is behind the rear axle.
The 300# only adds load to the rear axle, and Toyota is not concerned about that -- unless it causes the rear GAWR to be exceeded.
If more weight is ahead of the rear axle than behind it, the added weight will cause load to be added to the front axle
IMO, you're overthinking it.
Based on Toyota's WDH instructions, they do not appear to be at all concerned about the before and after height/loading ratios.
Weigh the unhitched TV fully loaded (including the WDH in the receiver and load in the bed).
Then attach TT and adjust the WDH per current Toyota instructions to return the front height to the unhitched value.
If you get the front end right -- the rear end will take care of itself.
Trucks are intended to sag in the rear when loaded.
If it sags more than you want, add air bags but be aware that adding air to the bags after the WDH is adjusted will change the load transfer.
Ron