Originally Posted by Jammer
... The whole point behind WD bars is to keep the rear axle suspension of the truck in an area where the spring rate is lower...
the primary reasons for using w/d bars are...
- to RESTORE steering axle loads to the UNhitched/normal load...
-and because the RECEIVERs are rated higher than 'on the ball' ONLY when w/d gear is used.
the stream is stressed by high amplitude/low frequency bumps/holes, and low amplitude/high frequency stuff (road surface)
but MOST of the load rides on the trailer axles and tires, not the tongue.
one would need to measure the htz of each type of vibe over a LONG period and assess the reaction of the metal to this...
this can't be simply computer modeled, because of the hi VARIABILITY in build characteristics for each stream...
in any one year or decade, or model change or FRAME change or SHELL change (skin/rivets/ribs/floors) that's part of the product history.
the axle manufacturer has changed, the specs have changed, the tv have changed, tires have changed and so on...
60s or 70s data (if it existed and it doesn't) would NOT apply to ANY current 'stream.
they are built VERY DIFFERENTLY now.
this has been done for example with HUMANS riding/sitting in vehicles,
such that we now know when htz is most damaging to the human spine with prolonged exposures...
the differences between exposure to HIGH amplitude and LOW amplitude stuff on the spine.
and the trailer frame flexes/extends/rotates when placed on the ball or with w/d tension...
this happens when PARKED as well as with movement.
but a 38 year old trailer with missing rivets or shell/frame issues is just an old trailer that's been used.
tired axles, old frame, old skin, old rivets and road weary and connected to a variety of mules over those 4 decades.
the skin/rivets are also stressed by WIND and air pressure while towing.
ANY aluminum riveted thing that old with miles would have loose/missing rivets or other signs of fatigue.
streams don't get inspected and regularly maintained like flying machines or boats as examples.
using 500 lb w/d bars with a 1000 lb tongue is POINTLESS for w/d unless the tv is otherwise modified.
much more on this stuff is posted here.
find the "body separation" thread and see hiho's work linked in post 35 above.