Quote:
Originally Posted by TyCreek
For highway travel in an RV, there's not much downside to higher spring rate transfer in my view. The sway bar compromise is when traversing uneven surfaces just as the wiki quote states. For traveling uneven dirt roads a disconnect would yield the best ride and eliminate spring rate transfer induced sway or "waddling" as in that wiki quote.
Why does a stiffer sway bar help highway handling? Here's a shot at trying to explain my observations for independent front suspensions: Wheels change their steering geometry as they travel up or down from center alignment |-| (both toe and camber). If you observe full droop or extension causing wheels to point like this /-\ toe (top down view) and camber \-/ (horizontal view). Full compressed goes the opposite for each toe and camber. With sway, one side is compress and the other is extended so consider the front wheels slightly shifting \-\ or/and /-/ as sway finally settles back to center |-|. Adding spring rate transfer reduces sway and in doing so it also reduces uneven suspension travel so there's less apposing steering geometry changes (win win for highway travel).
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I agree with you completely. I had been the shop foreman of one of the main two suspension shops in Fort Worth Texas. I worked at Fort Worth Champion Spring in downtown Fort Worth for many years. I have been going to school for alignment and other automotive technical applications since 1960. I just recently retired as The Honda Specialist in Fort Worth, Texas. I think I have probably learned a little bit in that time. Most of the problem with the Ford twin I-beam suspension seems to be with the fact that Ford installs a spring of a certain weight capacity and then they sell it to RV companies and heavy duty truck dealers that sell to welders, Hotshot delivery companies, and other heavy-duty companies that stick something on it 1,000 pounds or more heavier than what the chassis was designed to carry and they care nothing about alignment or the driver. That is when the toe goes way out and the camber goes negative and of course the truck or motorhome wanders all over the road and makes people want to buy all kinds of kits or fixit’s. It also seems like Ford always puts negative Caster on the right side. I never have figured that out but one "extremely well-trained????" "Ford front end Technician" told me one time "that it was so that if you went to sleep you wouldn't cross the center line and crash into oncoming traffic". Okay, I have been around long enough to have met some extreme morons that claimed to be mechanics. Fortunately, he went back to driving a truck which was also very scary.
To summarize my thoughts, the truck/motorhome needs to be level first. Then it needs to have some tow in. Never toed 0 or toed out. If the Caster is skewed either way it needs to be slightly from right to left or more positive on the right than the left.
Please, before you start adding parts/”miracle fix everythings”, get the truck level and properly aligned, slightly toed in and then go drive it. You still might need sway bars or better shocks but you might be able to save the money and take your lady out for a nice paid vacation instead..
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