SWAY: it's not just about trailers and hitches - TV set up

[richinny]

I’ve read many posts about sway problems. Issues included are: weights of axles, hitch set-up, tires & tire pressures, tv ratings, vehicle CGVW, etc.

One item i rarely see mentioned is tv wheel alignment! Having a vehicle that both tows and does snow plowing, is an enlightening experience.

When the height of a vehicle changes in the front, so do the settings of the wheel angles. i have found that the wheel 'toe' angle is very noticeably changed and felt. Different front suspensions react differently to a greater or lesser degree.

In an ideal setting, a tv wheel alignment is best done at actual riding height of the vehicle while towing. One way of duplicating the pitch is to weight the rear of the vehicle and raise the front to 'real driving height'. I got a strange look when I asked for the toe to be checked when the plow was on the truck but it showed that while the plow was off, the settings were within range but with the plow on, the reading changed to a less desirable angle. I clearly wasn't adding enough ballast in the rear to balance the truck. It made quite a difference in handling.

This explains part of why a weight distributing hitch improves sway so much. Besides not overloading one axle, it reduces the steering angle changes that make the steering feel loose.

any comments or opinions are welcome

thanks,
ricky

[bryanl]

Originally Posted by richinny

This explains part of why a weight distributing hitch improves sway so much. Besides not overloading one axle, it reduces the steering angle changes that make the steering feel loose.

it also explains why a weight distributing hitch is not always necessary. When the tongue weight will not overload an axle or change a steering angle, then it may not be needed. This is often the case for may pickups and medium weight trailers, especially if they have a heavy diesel in front.

Good handling for towing is not a trivial issue. As you note, there are many factors to be considered. Simple answers are often incomplete answers.

[dwightdi]

Product engineering and testing at Detroit and their other locations allow the manufacturers to properly set up the steering geometry for differently equipped model trucks. If you have a large trailer with signifigant tongue weight, you need to share that load (to some degree) with the front wheels. If you have a one ton dually, they have anticipated you will likely have some weight in the box and therefore their tests were conducted with some weight and the angles specified correctly for that load. You therefore do not need to shift much weight, if you have a smaller trailer with less than 800 pounds of tongue weight. This does not mean that you do not possibly might need a little sway dampening. My full size one ton Ford van had all the 460 cu in engine squarely over the front wheels, but still benefited from using a Reese twin cam when pulling my 31 footer. My tests on my one ton dually with the 8.1 in have shown it does not seem to need a W/D hitch to pull my '63 26 footer.