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There
are a lot of things that can
decide whether or not the car
you're looking at has a good
chassis. Is it an original frame
that's been boxed and reworked?
Was it built by a professional
in a jig from scratch? Are the
suspension components
aftermarket or are they modified
junkyard parts? Are the welds
solid?
Speaking
of Welds
There are three main ways to
weld metal together. Stick, MIG
and TIG. Although stick welding
is going the way of the
dinosaur, you still may see some
stick welded chassis out there.
It's very easy to tell if a
stick welded chassis is properly
welded. The bead will have
"flowed" into both
pieces of metal and it will be
visibly strong. MIG welding has
become prevalent on home built
cars of late. With inexpensive
MIG welders, the average guy can
afford to buy one. The problem
with MIG welders is that a bad
weld can appear to be a good
one. MIG is a relatively easy
process and can make a bad
welder look good. TIG on the
other hand is the preferred weld
on a good chassis. A proper TIG
weld will be visibly good and
easy to tell if it's burned into
the metal. A TIG weld will be a
much smaller bead than either a
Stick or MIG. TIG welding also
requires a good fit because of
the small bead. A MIG welder can
fill large gaps and make the fit
"appear" good.
Suspension
Components
Be wary of chassis that have
been built with junkyard OEM
parts. Is it because the parts
are no good? Not necessarily.
OEM suspension parts were
designed for the car they
originally came on and may not
work properly on a street rod.
For example: The popular Mustang
II front suspension was designed
for a car with the engine
directly over the suspension.
How many street rods have you
seen that this is possible in?
With the exception of a lot of
"fat fender" cars,
this is usually not possible and
the spring rates will be way off
for the average street rod. Some
people think they can cut the
springs down to drop the ride
height down to where it should
be but that doesn't change the
spring "rate". It
actually increases it and will severely
stiffen the ride. This also
throws off the geometry of the
front end and can cause handling
problems. Aftermarket front
suspension parts are designed
FOR STREET RODS with the correct
geometry and spring rates for
STREET RODS. If the junkyard
parts worked well, companies
like Heidt's, TCI, Scott's etc
would have never got off the
ground.
Independent
Suspension or Straight Axle?
This is the age old argument.
Which rides better? It's a wash
to put it simply. I've driven
MANY street rods and with both
type suspensions and I can tell
you that the ride is very
similar on either. I do think
the straight axle rides slightly
better though. The main
difference you will see with a
straight axle is the
"push" you feel in the
steering wheel when the steering
box "pushes" the drag
link. Which looks better?
Depends on the car. If you're
looking at a full fendered car,
it's all hidden so you don't
really see it anyway. This
really comes into play on a
hi-boy. Unless the nose is
pinched and an open wheel front
end such as the Heidt's is used,
the IFS looks terrible on a
hi-boy and makes the car look
unfinished (my opinion).
Rearends
and Rear Suspensions
The 9" Ford has become the
mainstay of the street rod
industry. Why? Because they're
plentiful, strong, fairly
lightweight and easy to change
gears in. That's not to say that
the car you're looking at should
only have a 9" Ford. There
are lots of factory length rears
that will fit nicely in a street
rod and I would not discount a
particular car just because it
has a factory OEM rear in it.
Most rear suspensions up to '34
models are generally
triangulated four bar, parallel
four bar or transverse leaf
spring. When you get to the '35
up, generally leaf springs are
the norm. What's the difference?
A parallel four bar runs
parallel to the chassis. This
design does not suit itself well
to a fendered car. In order to
use a parallel four bar you MUST
have a panhard bar to keep the
rearend centered in the chassis.
With a panhard bar, when you
turn or hit low spots in the
road, the ride height changes
and the bar will pull the
rearend one way or the other. If
you have fenders, you could get
into a rubbing situation. If you
have a hi-boy, there's no
problem running a parallel four
bar. The triangulated four bar
is by far the best way to go.
Less parts and the rearend stays
centered in the chassis at all
times. A transverse leaf spring
is just that. A leaf spring that
runs across the rear of the car.
Most of the originals were built
this way by Henry. I like the
transverse spring as it makes
the car more
"nostalgic" but the
ride isn't really better than
the coil over and the cost
savings is minimal between the
two other alternatives. I
realize a lot of this
information is more geared to
the builder and not the buyer
but it helps to know what you're
looking at and how it will
affect the car.
Stay
tuned, I'm going to rant about
Paint and Body next!
Reid |
