[RockyMtnRay]

Originally Posted by Steve97TT

This towing thread has made me curious about weight distributing anti-sway hitches...

Just to be sure I really understand the Equal-i-zer hitch...
Does the Equal-i-zer hitch plug right into the Sequoia hitch receiver
or does it require one to replace all or part of the factory hitch receiver?

Like all WDH it plugs into the existing hitch receiver. Nothing is done to the installed receiver.

Does anything on the Equal-i-zer have to be fit to a particular vehicle or is it easy to swap from one vehicle to another?

Again, like all WDH, it's readily swappable between tow vehicles. A WDH does require mounting "lift brackets" on the trailer tongue so it's a little harder to swap WDHs between trailers. However even that is possible if additional lift brackets are purchased/mounted on all trailers to be towed.

So how imperative is it that one go with a weight distibuting anti-sway hitch if towing 5k lbs?
I realize that the conservative answer is to install the Equal-i-zer but it is $400. (Of course I'd gladly spend $400 if it is needed.)

Not imperative assuming that the tongue weight is about 10% of the total trailer weight but it is an extremely good idea. Here's why:

When you attach a heavy trailer to the back of a tow vehicle, the rear of the tow vehicle sags but the cause isn't as simple as it looks. Specifically 3 things happen to the tow vehicle:

1. The tongue weight (e.g. about 500 lbs for a 5K trailer) is loaded onto the rear suspension. This is the intuitive action and the only one that most people ever consider. By itself, a 500 lb load on the rear suspension should drop it by about a inch.

2. The tongue weight is being applied well behind the axle. Through a teeter-totter like leverage with the rear axle as pivot, that tongue weight causes an unweighting or lifting of the front of the tow vehicle. The amount of unweighting is the ratio between rear overhang (distance from axle to hitch) and the wheelbase. I can't find a number for the rear overhang of a Sequoia but will use 4 feet as a reasonable number. The ratio between that and the 118 inch (10 feet) wheelbase is .40 which means that about .40 times 500 lbs or 200 lbs is being removed from the front of Sequoia. That unweighting of the front end causes it to rise about an inch; it also reduces the amount of braking and steering effort the front tires can produce.

3. Finally, the weight that comes off the front does not disappear into space; rather it's applied to the back suspension...further causing the rear to go down by about an extra half inch. So now your rear suspension has 700 lbs on it (500 lb tongue weight and 200 lb from unweighting the front suspension)

In combination these actions cause a distinct rearward squat...but only part of it is because the rear is pushed down and part is because the front is being lifted up.

You could fight the perceived squat by lifting the rear...but that still doesn't solve the problem of too much weight on the rear and not enough weight on the front.

By comparison, a properly adjusted WDH uses spring bars to apply about a third of the tongue weight to the front suspension, a third to the rear, and remaining third to the trailer's tires. Net result is the front and rear are only loaded with about 170 lbs each so the Sequoia squats equally front and rear but the amount of squat is pretty minimal because neither the front nor the rear loadings is very large. And you have more weight (instead of less) on the front so front tire traction for steering and braking is actually increased instead of reduced. The front suspension, being nicely loaded, also doesn't bounce around as it will when it's been unweighted. And the rear suspension is just nicely loaded instead of having to carry a rather large 700 lbs. A real win-win situation and well worth the $400 cost to get it.

Background -
I might occasionally tow a 3500lb sports car (very, very low center of gravity) on a 1300 lb aluminum dual axle flatbed trailer (link to the trailer). The trailer has electric brakes (for which I already have a Tekonsha Prodigy brake controller) I have never noticed *any* sway when towing the setup with a Chevy Duramax 2500HD (3/4 ton) diesel pickup with a weight carrying hitch and I've towed the setup for about 7000 miles through varied conditions in the midwest. (I have noticed some slight bounce on one particular section of uneven road.)

Thanks,
Steve

Sway occurs when the center of mass of the trailer is close to or behind the trailer's axles. A very front loaded trailer will be very sway resistant but it will put a huge load on the back of the tow vehicle. If the trailer is a bit sway prone...and the tow vehicle front suspension is sufficiently unweighted, then sway becomes very noticeable and very hard to control. The Chevy 2500HD has a very large weight in the front...and has a much longer wheelbase than the Sequoia so it does keep its front tires well planted and the ratio of tow vehicle weight to trailer weight is much higher than with the Sequoia. Nonetheless, the "slight bounce" you experienced is a classic sign that the trailer was sufficiently unweighting the Chevy's front end that its suspension was no longer acting normally. If you had used a WDH with the Chevy, you would have never experienced any noticable amount of bounce...the front would felt very "planted" at all times.


Hope this helps explain why you really do need a WDH when towing a 5K trailer with your Sequoia. Depending on where the trailer's center of mass is relative to its axle(s), you may not even need to use a sway control device as long as you get that tongue weight properly distributed so that a goodly amount of weight is being put on (not taken off) your Sequoia's front tires.

As a case in point, the TrailManor travel trailer I tow has a very high tongue weight (~700 lbs) relative to its total weight (~3800 lbs). That's an indicator that the center of mass is well ahead of the trailer axle (very front loaded) and consequently it is an extremely sway resistant trailer. It's so inherently sway resistant that the TrailManor company recomends that sway control not be used when towing because it will mask improper loading of the trailer.