Do I really need a bumpsteer kit?

imo, any lowered mustang needs a bumpsteer kit due to the severe angle it puts the tie rods at in relation to the rack and pinion.

Well if the car is lowered then the geomerty between the a-arms an tierods has change. Bump Steer kits are designed to get the tierods back in to the same plane as the a-arms.

Do you suffer from bs now? I did but when I had a good machanic align my ride things have gotten better. There and then I still have bs but its much less now. Point being its up to you.....

what exactly does bumpsteer feel like? i've lowered my 86 vert 1.5" in front and have no cc plates and to me it handles superb. it gets driven alot on twisty mountain roads, and the only difference i feel from before i lowered it is that it's on rails. like a slot car. so any insight would be appreciated. maybe i'm missing out on an even more awesome ride.

pudman said:

what exactly does bumpsteer feel like? i've lowered my 86 vert 1.5" in front and have no cc plates and to me it handles superb. it gets driven alot on twisty mountain roads, and the only difference i feel from before i lowered it is that it's on rails. like a slot car. so any insight would be appreciated. maybe i'm missing out on an even more awesome ride.

Click to expand...

Same here. i have cc plates though, but i would want to know what bump steer feels like aswell cuz i think it handles fine.

May I chime in with a question as well. My cobra is lowered in the front, with no CC or bump steer. I do notice my wheels are at a slightly un-natural angle. Also my isolators have been removed (so said the previous owner). But what does that mean...lol.

Sorry for the hi-jack, but this question was on my mind as well. Except my car is a 94 cobra.

if the tops of the wheels are tilted in then CC plates will help with that. On SN 95s the tie rod are longer so your bumpsteer issues, depending on how low the car sits, may not be an overly apparent problem.

You could just install some offest rack bushings couldn't you?

now I'm getting messed up. no bumpsteer kit...no cc plates.....no front wheel tilting in either direction....lower control arm very slight angle from parallel to ground....what am I doing wrong? With ford "C" springs and 1/2 coil cut, shouldn't I have issues? still need to know what bumpsteer feels like

BS is apparent if you know what you are looking for, but it is difficult to explain because it can show itself under many differnent conditions; hard cornering, bumps, hard braking. It is a state that changes the handeling conditions of the car when your front wheels are loaded on the road; the front end will become a little unstable.

CC plates will not change BS, BS is a factor of the geometry between your rack and spindles.

The offset rack bushings are a way to change the geometry, but these will also require a re-alignment.

If you are driving a vert, i would expect a significant amount of body roll that would affect your ability to feel what i am refering to, but most importantly if you think the car is driving fine then leave it alone - most people don't push their Fox to the limit or race them competitively to feel what i am speaking of.

thanks for the info Wallzy. as my sig states it is my DD with frequent canyon runs so "if it ain't broke...don't fix it"

Quote from Maximum Motorsports CC plate install instructions

BUMPSTEER
Bumpsteer is the term for the toe setting of a wheel
changing as the suspension moves up and down
over bumps, or with body roll while cornering.
There is a widespread myth that the tie-rod should
be kept parallel to the ground to avoid bumpsteer.
THIS IS NOT TRUE! What IS required is for the tierod
to be kept parallel to the lower control arm. That
way, as the suspension moves, the arc of the ball
joint and the arc of the tie-rod end do not transfer
any steering input to the spindle. As the car is lowered,
the tie-rod end and the lower control arm move
together, staying parallel. If offset steering rack
bushings are installed on a stock-geometry Kmember,
the tie rod end and the lower control arm
will no longer be parallel. Installing offset rack bushings
will INCREASE the amount of bumpsteer.
Ford engineers have actually done a very good job at
minimizing bumpsteer for a typical street-driven car.
Specifically, the bumpsteer was designed to cause
the front wheels to toe out during bump. This is a roll
understeer condition; the outside loaded tire will turn
to the outside of a corner as the body rolls. A car that
has a basic tendency towards understeer is more
stable and predictable. That predictability makes for
a safer street car.
Competition cars using stock K-member geometry
can benefit by fine-tuning the amount of bumpsteer
with an adjustable tie rod end kit. The MM Adjustable
Tie-rod End Kits provide an assortment of spacers,
in .015" increments, to help position the-rod end at
exactly the correct height. Adjusting bumpsteer on a
particular Mustang also allows correcting for individual
differences in suspension geometry caused
by production tolerances.
Offset rack bushings DO have a use, and are
beneficial if the inner control arm pivots have been
moved from the stock location. On MM K-members
the pivots have been moved upwards from the stock
height. In this case, raising the steering rack will help
match the geometry of the raised inner control arm
pivots, and reduce the required height of the
bumpsteer spacer stack at the spindle.
If offset steering rack bushings are used, they
should be made of aluminum. Polyurethane offset
bushings do not work. The urethane has too much
“give”, making it impossible to get the rack mounting
bolts tight enough to prevent the rack bushings from
rotating during hard cornering.

From my understanding unless it is a competition car or you use an offset rack, it is not necessary since ford designed the A arm and steering linkage to be fairly equal under compression or lowering.
Kevin

pudman said:

thanks for the info Wallzy. as my sig states it is my DD with frequent canyon runs so "if it ain't broke...don't fix it"

Click to expand...

When you hit a bump in one of your frequent canyon runs and your stang suddenly changes direction and veers into a gaurd rail....will you then express the same theology?

That is basically what your stereotypical bumpsteer effect is. Because of the change in geometry, a quick movement of the suspension as seen when hitting a bump or pothole will cause the wheel to turn while the suspension articulates. When extreme, it's actually quite dangerous...and I would think especially so during a "canyon run". Don't think that because you feel it handles great.....that you don't have it. Get a bump steer kit and have the damn thing re-aligned. Do it right or go home.

Another safer example of bumpsteer is just driving in a straight line down a crappy road at a safe speed...the potholes and lumps (are better for this example) will cause the car to "pull away" from you and change direction even though the steering wheel doesn't move or shift at all.

When I had coil overs and a 2" drop...this one section of road I test all my cars on...well...it was a mess. I had to get a kit for sure. On my other car I only run a 1.2" drop and just use some camber bolts and it's way less an issue.

Changing the camber of the car does not affect bumpsteer, they are independent of each other.

update on the bumpsteer issue. I installed offset poly rack bushings today and I definitely felt a difference. the steering feels much more solid and now I know what bumpsteer feels like. when I hit a dip on the freeway, the frontend doesn't get all wishy washy. it just keeps going straight and solid. maybe 23 year old stock rack bushings were a problem ya think??? so thanks again for all the info and suggestions

If you installed offset bushings in your rack you are going to need to check your alignment - these bushings will affect your toe.

alignment was checked and adjusted. everything just wonderful

Awesome!