BMW Thrust Arm Kit - Syncro Design Works SDW E70

The Syncro Design Works monoball bushings compared to a traditional hydrobearing or solid rubber bushing offer a range of multi-axial movement, where OEM bushings only pivot on a single axis, similar to a gate hinge in motion. OEM bushings, even when new, allow more deflection than preferred for optimal performance and have a limited service life. Syncro Design Works rear trailing arm bearings are lubricated and sealed for maintenance free operation, which makes them the last tension strut bushings that your vehicle will ever need.

What is a monoball?

A monoball is a spherical bushing (ie ball joint) that replaces stock rubber bushings and eliminates inherent deflection created by OE rubber bushings. Unlike solid or polyurethane bushings, monoballs allow for complete unimpeded suspension movement while allowing for a completely rigid central mounting point. It is truly the best of both worlds and is best utilized in applications where the pivoting point is both up and down as well as side to side.

Why a monoball?

A monoball bushing provides full articulation of the suspension with no binding or deflection. A stock rubber bushing is rubber vulcanized to a metal sleeve which deflects (twists) with each suspension movement. Rubber bushings provide great comfort but when pushed in a performance application they allow for undesirable suspension movement and slop. Under heavy braking rubber bushings can deflect quite a bit making the car unstable. Stock rubber bushings also provide unstable and unwanted suspension movements on uneven road surfaces as well. A mono-ball being a solid mounting point with no room for play around its pivot point creates a completely rigid mounting point while allowing appropriate suspension travel and movement. It is the ultimate solution for a complex multi-link style suspension.

Why not a polyurethane bushing?

Polyurethane is good for certain applications such as mounts that don't require complex movement (sway bar mounts, engine mounts, subframe mounts, etc). For a control arm such as a thrust arm the movement at the bushing is both up and down as well as side to side. Essentially polyurethane in this type of application restricts suspension movement. In some applications the centering sleeve for a polyurethane control bushing can spin with suspension travel causing the inside portion to wear, resulting in noise, and eventually causing suspension slop and play.