alignments

From: Frank Ball (frankb@cougar.sr.hp.com)
Date: Mon Mar 16 1998 - 17:51:12 EST


} > I would like to know exactly how you adjusted your toe-in using twine.
} > Bruce
}
} I just set out 4 jackstands, ran twine along each side of the truck,
} measuring with a steel tape until I was reasonably sure I had a
} rectangle that was square with the truck. I then adjusted each tie rod
} until the toe-in was virtually zero (each front wheel was parallel to
} the string) AND the steering wheel was square with the world. I kept
} track of what I had done to each tie rod so that if I discovered that I
} had dug myself into a hole, I could return to where I started. It
} probably won't compare to a professional alignment, but it has worked
} well and eliminates leaving the truck somewhere for a day only to be
} told that "the alignment is within specs".
}
} Marc Robertson
} marc@blackberry-ridge.com

The front tires are spaced an inch or so farther apart than the rears,
on a 4x4 there is another inch or so added to the front wheel spacing.
So using your twine method I would expect that you now have a small
amount of toe-out.

I used to have a '62 Ford F-100 with a single I-beam front axle. On
that truck it wasn't too hard to measure between the front tires with a
tape measure and subtract the measurement of the front edges of the
tires from the rear edges of the tires to get the toe-in. With the
single I-beam the toe did not change as a function of suspension travel.
Independent front suspension makes this much more complicated.

The Dakota toe-in spec ('95 2WD) is 1/8" +- 1/16" (same as my '62 Ford).
This is a pretty reasonable number. My old Datsun PL510 was about 5/16"
which was pretty extreme. I think (but I am uncertain) that a small
amount of toe-in was desireable for two reasons: 1) stablility from
front end oscillations (something my Datsun would do with very worn
tires), and 2) better steering response (I hear the Acura NSX scrubs
it's tires pretty hard, but it keeps the handling very repsonsive. The
front tires are already slightly turned in, so the "slack" is taken up
already when you initiate a turn). If anybody knows better I'd like to
hear more.

All Dakotas wear the outside edges of the front tires to some degree.
Some worse than others, it's hard to compare over the net. A friend got
a '97 and had the dealer realign it because of front tire wear, and he
is happy with it now. I also had him raise his front tire pressure
which helps. I use about 40 psi in the front tires and rotate at 6-8000
miles. I get some extra wear on the outside edges of the front tires,
but it isn't really bad.

I would think that a better solution than fiddling with the toe-in would
be to reduce the camber ('95 2WD spec = .5 +- .5 deg) to zero. This
would help the tire wear, and I think it would also reduce understeer
slightly. At least one list member has done this (and set the toe to
zero). I may have the camber spec backwards, but what I mean is the
front wheels should be tilted in more at the top edge (or tilted out
less?).

A rear anti-sway bar will shift some of the weight off of the outside
front wheel and onto the outside rear wheel under hard turning, so that
may help the front tire wear also. (I have the Addco rear anti-sway
bar).

So I have a question for you guys who have done these alignments: how
hard is it to get the caster and camber both set exactly to where you
want them? Are you happy to get it within the spec window, or is it
easy to really dial it in perfectly? How interactive are these two
settings (castor and camber)? When you set one, does it unset the
other?

Frank Ball 1UR-M frankb@sr.hp.com (707) 794-4168 work
Hewlett Packard (707) 794-3038 fax (707) 538-3693 home
1212 Valley House Drive Kawi KDX200, Yamaha XT350 YZF600R Seca 750
Rohnert Park CA 94928-4999 '95 Dakota SLT Club Cab V8 5-Speed 2WD



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