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What is "Bump-Steer"?
A change in the toe setting (alignment) as the wheels move up
and down is referred to as bump-steer. This condition is
responsible for the twitchy handling you may have experienced
during transition from the straight line into a corner and can
be the reason for most high speed instability problems. Zero
bump-steer is ideal. The rear suspension on 84-87 Fieros is not
ideal and bump-steer is to blame.
In most cases it is possible to improve the bump characteristics
of a vehicle by moving steering linkage pivot point locations
and/or changing the lengths of the tie rods. The Fiero is
essentially a mid engine car with a front wheel drive unit
mounted mid-ship. The steering knuckles from the front drive
vehicle are retained and are tied off to the frame (engine
cradle) to eliminate the steering. Unfortunately the steer
effect is not fully eliminated and we are left with bump-steer.
Furthermore, modifying the tie rod mounting points and/or
lengths will only "help" the situation and only within a certain
range of the suspension travel, creating what might be called a
"sweet spot".
Most enthusiasts know that lowering the center of gravity by
lowering their car will greatly improve handling. Many factors
affect just how low is practical. Will you use the car primarily
for racing, where performance is everything, tracks are as
smooth as glass and ground clearance need only be a couple of
inches? Perhaps you want a certain stance where lowering the
vehicle 1" or 1.5" is all that's required. Are you building a
kit car requiring a 3" drop just to make it look normal? As you
can see, lowering a car means different things to different
people.
We thought it pointless to design a single "sweet spot"
bump-steer fix when everyone's sweet spot is in a different
spot. Our solution was to make changes to the geometry that will
totally eliminate the bump-steer through the entire range of
suspension movement, making it universally applicable.
FAQ
What exactly is included in the kit?
2 control arms, 2 toe links, 2 knuckle adapter brackets.
Control arms come with urethane pivot bushings, sleeves and
weather-proof spherical bearings at the knuckle assembly.
Does it allow use of standard struts?
Yes.
Are there modification to the frame involved, welding, or
other heavy mods to the car?
There are no frame modifications required. The knuckle
assembly requires some minor modifications. (One hacksaw cut
1 1/2" long.) The steering arm taper is drilled out using
the fixture provided.
Does this use standard lower ball joint?
No.
How much road testing have you done to prove
road-worthiness?
This product has gone through our usual testing regime.
After 13 years of successful designing and manufacturing of
Fiero suspension upgrades, you can rely on the high quality
found here at Held Motorsports.
Does it allow use of a rear sway bar?
Yes, click Sway Bars for more information.
Is this set up available in a wide-track version?
Yes, we have standard and wide track versions. Please find a
photo of the wide-track Bump Steer kit immediately below.
Does the kit change the offset of the tires or is it just
a stock replacement?
It does not change the offset.
I would like to purchase the 13" brake system, the slalom
front and rear suspension, and the bump steer kit. Will I
notice that much difference with the bump steer kit, and can
it be used in conjunction with the other components I have
previously listed?
The Fiero Rear Bump Steer Kit will noticeably improve your
ride. It can be used in conjunction with all the products
you have mentioned.
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