When To Use a Weight Distribution Hitch
The most obvious sign of someone not towing correctly is when both the tow vehicle and trailer sag at the hitch. It is as unsafe as it is unsightly. The downward force on the rear of the vehicle reduces the downward force on the front, reducing both steering traction and front brake effectiveness. Meanwhile, the rear wheels have suppressed suspension travel, and the rear axle and brakes are at risk of overheating. The imbalance also reduces vehicle stability which is bad at any time, but worse when you are towing. The Dieffenbach GM Superstore knows how you can avoid this.
Sagging at the hitch is less likely the result of a vehicle pulling a trailer over its maximum towing capacity than excessive tongue weight, defined as the actual amount of trailer weight forcing down on the hitch ball. An ideal tongue weight for a conventionally towed trailer is 10-15% of the total trailer weight. Below 10% indicates too much weight at the trailer rear, which threatens excessive trailer sway. Above 15% can result in the sagging described above.
Trailers with fixed content, like camping trailers, were likely designed to be within this tongue weight range. and will have that figure as part of their specs. Adding excessive heavy gear in the front or back can change the figure, however. When working with trailers with variable contents such as cargo, vehicles, or livestock, the tongue weight is entirely up to the load distribution which you may or may not have full control of. Vehicles equipped with rear air springs may seem to alleviate the sagging problem on their own by pumping up the air until the vehicle is level again, but air springs will not significantly return the weight to the front. The real solution for GM pickup trucks and truck-based SUVs like the Tahoe, Suburban, Yukon, and Yukon XL, is a Weight Distribution Hitch (WDH).
What is a Weight Distribution Hitch?
“Poorly understood, absolutely essential, and seldom used” is how Alex Dykes of Alex on Autos described weight distribution hitches. Their purpose is to distribute the tongue weight evenly across the tow vehicle’s front and rear axles as well as to the trailer axle(s), which it accomplishes by forcing the hitch connection to be parallel with the road. The industry term for this is Front Axle Load Restoration (FALR). Ideally, FALR will return 50-100% of the weight lost from the front axle.
The description makes it sound like a WDH must extend to the front axle and a trailer’s axle, but what they do instead is force the frame of each vehicle to do the FALR work for them. It starts with a height-adjustable hitch. Torsion-acting “spring bars” mount on each side of the hitch ball on one end, with the other ends mounting to each side of the trailer’s front A-frame at about 23 to 35 inches back from the coupler. By rigidly connecting the frame-mounted hitch to the trailer frame, the spring bars force a parallel connection between the tow vehicle and trailer and greatly reduce vertical pivoting at the hitch ball. For the tow vehicle, this both levels the body and forces weight back on the front axle while at the same time forcing weight rearward on the trailer. The spring bars are designed to flex enough to enable turning and allow a small degree of vertical articulation to account for uneven surfaces, but always returning to the parallel connection.
When to Use a Weight Distribution Hitch?
The weight ratio between a tow vehicle and a trailer is always a factor in trailering stability. The greater the trailer weight, the greater likelihood of instability. As a general rule of thumb, you should consider using a WDH when the trailer weighs 50% or more than the tow vehicle. For example, a 2023 5.3-liter V-8 powered 4WD Silverado 1500 Crew cab / short bed weighs about 5,070 pounds. Though it has a maximum towing capacity of 9,000 pounds, any trailer above 7,600 pounds should be pulled with a WDH. If the tongue weight exceeds 10 to 15% of the trailer weight. a lower weight threshold should be considered.
Because of the load WDHs place on the frame, they are not compatible with “car-based” models with unitized body frames, such as the Acadia, Terrain, Equinox, Traverse, and other Chevrolet crossovers. This is another reason why body-on-frame vehicles such as GM pickup trucks and big SUVs make superior tow vehicles. Trailers with surge brakes are also not compatible with certain types of WDHs.
Keep in mind that WDHs do not increase a vehicle’s towing capacity and should always be used within that capacity. More setup time and activity are required with a WDH than with a conventional hitch. There are settings regarding hitch height and spring bar mounting to consider, and setup requires a level surface for both the tow vehicle and trailer. With a trailer with a fixed load like a camping trailer – you can pretty much set it and forget it – again, barring excessive personal additions on one side of the trailer axle. But if the trailer or trailer load changes, adjustments will be needed with each use.
Most WDHs cost between $250 to $500, though some can cost many times that. While certainly more than a conventional hitch, it is probably a fraction of either your trailer or tow vehicle, both of which will be better protected by improved towing stability. If you are towing something fairly heavy, a WDH is the way to do it correctly and show you know what you’re doing. If you have any specific questions about towing with your truck or SUV, contact one of our professionals at the Dieffenbach GM Superstore.