Re: Worn ball joints

[Howard R Pletcher <n9ads@domain.elided>]

On Mon, 08 Mar 1999 13:34:52 -0700 Tom Mandera <tsm1@domain.elided> writes:
>
>Tires are wearing on the outside edges up front.  Toe-in is actually
>just a little bit of toe-out at the moment.  When I had excessive
>toe-out, the tires wore on the inside.  Now the top of the tire appears
>to be more "out" than the bottom which is "in".
>
>
I can't say your camber isn't a problem, but I wanted to clarify that a
Scout "should" wear the outer edges of the front tires.  Have you ever
heard the term "Steering Ackermann", named for the guy that defined how a
vehicles steering geometry should be laid out?  He said that in a turn,
lines drawn through the axis of each front wheel and through the shafts
in the rear should all meet at a common point out in the center of the
turning circle.  A Scout's will not (I don't know why, don't ask--maybe
the engineer that laid it out missed class the day they covered
Ackermann).  If you realize this and then go look at a Scout in a tight
turn, the outside front wheel looks like it's turned too sharply and you
can feel, hear, and see it scrubbing on the pavement.  I'd think it would
take lots of camber to produce the wear that one full turn a day on dry
pavement will produce.  Since the steering geometry didn't change, a
Traveler/Terra should be even worse than a 100" because of the longer
wheelbase.  This is a big problem in big trucks that may come in
wheelbases from 120" all the way up to 250"--theoretically you need
different steering arms for every wheelbase to get it right and minimize
tire wear.

About the only bandaid for this is to remount your tires with the inside
on the outside by the time they approach 1/2 worn.  It seems to me that
increasing caster might also help reduce it a little because the tire
will not tuck under quite as much.

Howard Pletcher
Howteron Products Scout Parts

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