Seraphitia102 said:
Will the bumpsteer kit do me anything else on top of getting rid of some bounce?
NO!...
You don't need a bump steer kit.... here's why you don't see one on the MM site.
From MM instructions.
BUMPSTEER
Bumpsteer is 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 myth that the tie rod should be kept parallel to the ground to avoid bumpsteer. THIS IS NOT TRUE! What IS required, is that the tie rod be kept parallel to the lower control arm so that as the suspension moves, the arc of the ball joint and the arc of the tie rod end do not cause any steering input to the spindle. As you lower your car, the tie rod end and the lower control arm move together, staying
parallel. If you install offset rack bushings on a stock geometry K-member, you are making the tie rod end
and the lower control arm NOT parallel. You will actually CREATE bumpsteer by installing offset rack bushings on a stock K-member.
Ford engineers have actually done a very good job at designing a low level of bumpsteer for daily driven cars. Specifically, Ford has designed the bumpsteer to toe out the front wheels under bump. This is a roll understeer condition; the outside loaded tire will turn to the outside of a corner as the body rolls. This condition is designed by Ford by positioning the tie rod end slightly low relative to the steering rack.
Increasing caster raises the tie rod end relative to the steering rack. Increasing caster up to half of the
adjustment range with our Caster/Camber Plates will actually HELP bumpsteer and help performance by
reducing roll understeer. If you increase caster beyond half of the adjustment range, the bumpsteer curve will shift toward toe IN under bump, or a roll-oversteer condition. In this case, it is beneficial to raise the rack, but only by about 1/10 of an inch. Offset rack bushings raise the rack far too much. The best solution is to lower the tie rod end using a bumpsteer kit (MMTR-3,-4). See our test results in the July 1993 issue of Super Ford for details.
Competition cars using stock K-member geometry will also benefit from an adjustable tie rod end kit (MMTR-3,- 4). These kits provide an assortment of spacers in .015" increments to best position a rod end at exactly the correct height; thus taking into account suspension geometry tolerances.
Offset rack bushings DO have a purpose and may be beneficial if you have raised your inner control arm pivots using an aftermarket K-member. In this case, raising the rack will help match the geometry of the raised inner control arm pivots. If you do use offset rack bushings, be sure to only use aluminum bushings - polyurethane offset bushings do not work. The urethane has too much “give”, and therefore it is impossible to get the rack mounting bolts tight enough to prevent the bushings from rotating during hard cornering.
