Originally Posted by Freedomrider
By the way, if weight has to be shifted form front to rear axle or vice versa, how would you do that?
As stated earlier, IMO, you already are transferring too much load to the front axle. To transfer less load to the front, you can increase the number of chain links under tension and/or decrease the amount of rearward tilt of the ball mount. If you do either of these, you might need to re-center the cams in their bar detents. And, it is quite possible the "fish tailing" you are observing is because your cams are not centered with the current adjustment.
The reason for my recommendation of less load transfer is based, in part, on the following.
I think the reason Ford, Chevrolet/GMC, Toyota, Equal-i-zer, and others have changed their weight distribution specifications 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 front axle load is:
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).
A related explanation from a representative of the company which manufactures the Equal-i-zer hitch was first posted here
. It says:
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
. (Underline added for emphasis.)
Ford now says the Front Axle Load Restoration should be approximately 50%.
Equal-i-zer now says the Front Axle Load Restoration should be between 50% and 100%.
Chevrolet/GMC specify 100% or 50% depending on tow vehicle capacity and trailer weight.
Equal-i-zer's revised instructions specifically state:
You have most likely achieved good weight distribution adjustment if your measurements show the following with the trailer coupled and the weight distribution engaged:
1. From the coupled without weight distribution measurement, the front wheel well measurement is at least halfway back to the original uncoupled measurement. See line C on Front Wheel Well Measure Chart.
2. The rear wheel well measurement is somewhere between the uncoupled height, and the coupled with no weight distribution height. It should NEVER be higher than the uncoupled height. See line C on Rear Wheel Well Measure Chart. See Figure 19.
As with most towing-related discussions, you will receive a variety of opinions when you seek advice. It's up to you do decide which approach will work best for you.