towing with suv???

APT wrote:
The "80%" rule, guideline, whatever people call it often covered RVing vs. other types of trailers that are far easier to tow. It also generally covered the payload limitation of half ton vehicles and smaller for family RVing. As Ron suggested, there is no such thing as an 80% anything. Learn what each limit is for any given TV with respect to RVing and you can operate up to and some people believe over certain ratings.

The earliest
(12/04/00) reference I can find in Open Roads Forum to a towing-related "80% anything" is in this post:
"---

Find out how much your vechicle can pull then do not exceed 80% of that tow limit.. The 80 / 20 rule.

---"

It's interesting to note that this early 80% rule appears to be based on the 80-20 rule which has nothing to do with towing-related safety factors.
As with many towing myths, this application of an "80% rule" was based on a fallacious premise.
Unfortunately, if an opinion gets repeated enough times, some people begin to believe it is a fact.

In order for any xx% rule to have any meaning, one should specify: xx% of WHAT, and why XX%?
We previously saw a reference to "80% of rated towing capacity", with no definition of "rated towing capacity".
Ford specifies values "Maximum Loaded Trailer Weight" and then says the weight of additional options, passengers, cargo and hitch must be deducted from this weight. So, which number does the 80% apply to.
GM/Chevrolet specifies values for "Maximum Trailer Weight" and also lists weights which must be deducted. Again -- 80% of what?
Toyota specifies values for "maximum gross trailer weight", but does not say anything about deducting any weight carried in/on the TV.
Seems to me that, if the objective is to impose an arbitrary "comfort factor" on how hard the TV is allowed to work, the factor should be applied to the TV's GCWR rather than to some "rated towing capacity" which has no universal definition and often is mis-interpreted.

And, other than some mistaken application of the 80-20 rule, why should the "comfort factor" be 80%? If 80% is good, would not 70% be even better?
OTOH, if the TV manufacturer is comfortable with 100% and is willing to provide warranty coverage for 100% usage, why should we be telling people they must limit towing load to 80% of some undefined value?

All too often it is implied that, if one keeps the trailer weight below 80% of the "rated towing capacity", the other weight-related considerations will take care of themselves. This is true in some cases -- but not in others.
Consider a TV with published towing capacity of 9500# and published payload of 1500#. Blindly applying an 80% rule could give "comfort" to a person towing a 7600# TT which might have a TW of 1000#. However, that "comfortable" towing combination might actually be going down the highway with TT GVW in excess of GVWR.

Application of an arbitrary "comfort factor" to an ill-defined capacity value does not ensure a safe and nicely-handling TV/TT combination.
As APT stated, we should be trying to help prospective purchasers understand the reasoning behind all manufacturer ratings -- and the need to comply with all of them.

Ron