Jeff,
I'm guessing/hoping Datsun doesn't list specs because this is a Sports
Car. If you go to a good shop with techs that understand what they are
doing/why they are aligning the car - you should have no problem getting
the car aligned.
Basically, have an alignment done to encourage the car to respond as you
like, and protect against tire wear to fit your budget.
Here is a little alignment info to get you going:
TOE: This refers to the degree that the tires are parallel. A perfectly
parrallel pair of tires is said to have zero or neutral toe. Most
manufacturers spec a slight toe-in (that is to say that they set up tires
a little pigeon toed versus west-footed). This prevents tramlining (tires
following grooves in road instead of steering inputs), and generally
promotes understeer at turn-in. Neutral toe or slight toe-out will
provide you with faster turn-in, but neutral tends to tramline and toe-out
wears tires pretty quickly when combined with camber. I prefer neutral
toe as it turns in fairly quickly, but it is much easier on the tire wear
(read pocket) than a toe-out setup. I would set up a dedicated track car
with neutral toe because fast turn-ins at speed can get hairy, or a
dedicated autoX car with slight toe-out to get the car to turn quickly.
Camber: The degree to which the top of the tires lean in (/_\) or out
(\_/) relative to the contact patch. When a car is turning, lateral
forces work in concert with the downward gravitational force. So, by
setting up a tire to lean in (negative camber), you are placing it in a
state of readiness to best handle the lateral forces. Negative camber
costs you tire wear (inside of the tires) when you spend too much time
traveling straight. If you are attracted to twisties, a negative camber
setup can actually prolong tire life - but few of us have that many
twisties available. Manufacturers again tend toward slight positive
camber to promote understeer.
Caster: This is the most difficult to explain. It is the degree to which
camber is made more negative as the wheels are turned. Just realize that
it is rarely adjustable, and the manufacturers set this one up for the
type of ride. I.e., Mercedes is famous for very high caster. High caster
is noticed primarily by how much the car tends to return to straight track
following a turn. Low caster cars just keep turning - high caster cars
auto center. As you can guess, high caster can substitute for negative
camber to an extent. It is generally only adjustable by changing the
suspension geometry radically.
So, the point of an alignment is to set optimal toe and camber given a
fixed caster setting. And, you can make these determinations yourself.
Toe figures are generally expressed as plus or minus a couple degrees,
Camber figures can get a lot more radical and can extend to the tens of
degrees, but are extremely radical and of questionable benefit past about
10 degrees.
My suggestion is zero toe and as much negative camber as is available by
adjustment (prolly 2 to 5 degrees tops, but I haven't looked at roadster
alignment yet). Gives a quick, performance oriented response while not
being too bad on tires as long as you remember to seek out the twisties
often. If you are consistently heating up the inside of the tires more
than the outside, you may want to dial the camber back.
Hope this helped. There are many places on the web that do a more
thorough (i.e., with pictures) job of explaining suspension geometry
issues. Don't hesitate to search, but if you get caught "stringing" your
car for a self alignment - plan to spend all day the first time.
Milton
On 28 Aug 2002, at 13:05, maurell@bellsouth.net wrote:
> alignment done. they say they don't have the specs? can anybody help me
> with that. my clymer manual list some specs, should that be enough?
milton <milton3@pobox.com>
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