The geometry of the E.R.A. front suspension gives good
The roll center height
is designed to complement
suspension, giving handling characterists that
and safe, or as safe as any car with this much power and a 90"
steer" is the toe-in change
that the front or rear tire takes as it travels up or down. With poor
characteristics, a car will dart from side to side over bumpy roads and
potentially dangerous transient reactions.
design of the E.R.A. 427SC geometry,
bump-steer is near 0 over the full range of the
details on the Longacre web site)
- our wheel travel is
extremely generous:: More than 3"
jounce and rebound directions so that you can lower or raise the car
somewhat without worrying about running out of travel.
car goes where you
point it, even under poor road conditions.
The modified Flaming River rack and pinion steering
gear has 3.1 turns lock-to-lock, with a 34 foot turning circle.. Effort, even without power
is fairly light, and the steering has plenty of feel. Custom
tie rods and lower steering column are
also supplied with the kit. The optional E.R.A. steering column
wood steering wheel are visual duplicates of the original parts. E.R.A.
the upper and lower control arms, and we supply a lightweight steering knuckle
for quicker response.
Modified GM uprights, new
upper control arm cross-shafts, ball-joints,
and fasteners are all
included in the standard
kit, ready to accept very large vented brakes on
stock or optional
pin drive hubs. A large anti-sway bar is optional.
|E.R.A. makes the upper and lower control
arms, and modifies the included GM
for quicker response.
Here you can also see the optional anti-sway
and optional double-adjustable
Yes, even damping
can be changed with a screwdriver without removing the unit.
We have duplicated the original car's "X"
to complete the correct "look". Front
shocks are mounted to the X just like the
original Cobra. We recommend
our custom made Spax units with external adjustments for both damping
height, but you can use any brand that meets the proper specifications.
Little Independent Front Suspension
the time of the "birth" of
independent front suspension, it was
conventional wisdom that the contact patch must
travel in a straight
vertical line as the car encountered bumps. It made some
then, when it was not unusual to drive on very uneven dirt roads.
That movement constraint required that the roll center had to
be at ground level. The shorter upper arm derives from the time when
were almost always parallel to the ground. With narrow tires and high
of gravity, the angle of the contact patch wasn't that important with
narrow tires anyway.
the upper and lower arms are horizontal with the car at normal ride
The arms may not be horizontal
at ride height.
short/long control arm design was created to keep the
of the contact patch in a straight vertical line under bump and
The tire tilts in going up and also tilts in going down.
If you want to see some "interesting" contact patch movement,
analyze a McPherson/Chapman strut. Some excellent cars use
The best designs compensate by using very long control arms
to control roll
At any rate, the (optimal) object is to
keep the roll center at a
height, the tire vertical under bump and vertical
when the car rolls.
That Can't Happen
in the real world.
Smooth roads and wide tires have now
changed what we look for in
geometry. We are more concerned with keeping the tires
roll. Consequently, the upper and lower control arms have
non-parallel to keep the inside tire rotating (in front view) as it
down. That's how we ended up with the second design.
Era Replica Automobiles