
The
factory minimizes this suspension bind by using compliant rubber
bushings. These soft bushings help accommodate the necessary motion of
the suspension's arms during body roll. However, the rubber bushings do
not provide much in the way of forward and aft support which can cause
wheel hop during hard acceleration and braking.
It is
common to replace the stock rubber bushings with polyurethane bushings
to resolve the shortcomings of the factory's soft rubber bushings.
Polyurethane bushings eliminate wheel hop, reduce axle deflection, and
improve straight line traction. However, the downside of polyurethane
bushings is they prevent the necessary movement of the suspension's
arms during body roll, which in turn produces significant binding in
the suspension when the vehicle is cornering. The polyurethane bushings
also place high stresses on the suspension arm mounts on the vehicle.
Polyurethane bushed suspension arms do not allow for rotation of the
arm during cornering because of the stiffness of the bushings.
The
Del-Sphere Pivot Joint Design:
The Spohn Performance Del-Sphere pivot joint solves the shortcomings of
the factory rubber and aftermarket polyurethane bushings. Our
Del-Sphere pivot joint incorporates a spherical ball which is
surrounded by delrin bushing cups. This combination allows the control
arm to articulate like a spherical rod end (28 degrees of available
rotation) during cornering but the spherical ball does not allow the
bushing to deflect during acceleration. This provides for great
straight line traction like polyurethane bushed control arms but
remains completely bind free like a spherical rod end during cornering
for predictable traction in the corners.
Think of the
Del-Sphere pivot joint as a Delrin bushed spherical rod end. After over
a year of R&D testing here at Spohn Performance on a streetable
spherical joint the Del-Sphere pivot joint is the final result.
Designed and manufactured exclusively by Spohn Performance, we have
taken street suspension performance to the next level. Our Del-Sphere
pivot joint features a one piece forged and heat treated chrome moly
housing, a heat treated and chrome plated chrome moly spherical ball,
Delrin bushing cups, heat treated retainer washer and snap ring, heat
treated and chrome plated chrome moly threaded adjuster ring, an
external grease fitting and a beautiful silver zinc plated housing
finish.
The Delrin bushing cups absorb shock and road noise so you get
the quiet and smooth ride of a bushing as well as 28 degrees of
rotation! Our Del-Sphere pivot joints will always ship to you fully
assembled, however, we also offer an optional adjusting tool
that will allow you to do two things. First, you can disassemble the
Del-Sphere pivot joint for cleaning, inspection, etc. Second, you can
adjust the amount of friction on the spherical ball. Do you want a very
low friction pivot joint or a very tight pivot joint? It's up to you,
the amount of tension can be easily adjusted by using our
adjustment tool to tighten or loosen the end retainer ring. What that
also means is if over time and miles the tolerances open up you can
simply re-adjust the retainer ring and have your pivot joint as tight
as it was the day it was brand new. We doubt you'll ever need to
replace the Delrin bushing cups, but they certainly can be. Unlike a
spherical rod end, the Del-Sphere pivot joint is 100% rebuildable.
What
is Delrin, and why did you choose to use it?
Delrin is an acetal homopolymer made by DuPont. It is characterized as
having an excellent combination of physical properties that make it
suitable for numerous applications. With extremely low moisture
absorption and a low coefficient of friction (self-lubricating), Delrin
is uniquely tailored for wear applications in high humidity or moisture
environments. Delrin will maintain constant physical properties under
high moisture conditions and out-perform nylon or polyurethane under
these conditions. Delrin has a 10,000 psi tensile strength and a 120
Rockwell Hardness rating making it ideal for our Del-Sphere application.