If you turn your wheels slightly in one direction, your tires will track
paths of two large circles, one inside the other -- even though both tires
are angled equally in the same direction, they are tracking different
diameter circles. The inner tire will be trying to go less into the turn,
that is, straighter but this reaction is not noticeable.
If you turn your wheels fully in one direction, your tires will track paths
of two smaller circles, one still inside the other. The inner tire will be
working harder to go less into the turn and this reaction is more noticeable
(inner tire shuddering, skipping, squealing, etc. more than the outer tire)
because of the smaller turning circles tracked. It is even more evident in
I wasn't even considering the rear tires in my reply but you do bring up an
interesting point with the front-rear tires in 4WD locked TC. Nevertheless,
the original poster did not specify what vehicle he was referring to, hence,
it was unknown how much Ackerman, if any, he had.
All vehicles with a front driving axle also have a differential in the front
Some 4x4's have a differential in the transfer case to allow
for differences in speed between the front and rear axles, others
use a viscous coupling, which achieves the same thing...and still
others use clutch packs to achieve this.
Why? I was simply commenting on your comment. I don't
remember there being any rule that says I have to respond
to the OP.
In your original answer to the post, you pretty much completely
missed what he was asking. You started talking about the relative
circles that an inner and an outer wheel will make when turning
left or right. Steering linkage geometry takes care of what you
are describing. Differentials are designed to take care of the
different "speeds" the wheels are traveling, the steering linkage
geometry takes care of the different "size" circles the tires
are going around. One is about angles, the other about relative
If a four wheel drive vehicle is in the 4x4 mode that is locked
from front to rear....you are going to experience "crowhopping"
which is what the original poster is complaining about. There
isn't anything you can do about that...it's normal. If you have
some sort of differential action in the t/case, "crowhopping"
will be either non-existant, or very minor.
Heheheheh, no need to get your knickers in a knot fellas. Please don't get
offended -- just trying to stay on topic with the original question which,
incidentally, was followed by a comment that (paraphrasing) regardless of
which way he turned the steering wheel, it still wants to pull the other
way. Steering linkages (i.e., Pitman arm angles) do take care of, but
obviously does not compensate for all of what was causing his observations,
and likewise for differentials. Otherwise, he wouldn't be having those
"hopping" symptoms in the first place (???); /QED. Hence my descriptions.
So, in answer to his question, "Yes, it's more normal for vehicles with
'dumb' steering systems." I was surprised nobody added 4-wheel steering...
Thanks DWB, that was off the top of my head trying to remember my
professor's descriptions in college 27 years ago -- he predicted 4-wheel
steering's main use would be for ease of parking and maneuvering his boat
Are you using 4wd on the pavement or a hard surface?
It's only for low traction surfaces, where the tires can slip a little...
otherwise, you can damage your transfer case by using 4wd with no wheel slip....
Please remove splinters before emailing
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