How Rear Multi-Link Suspension Really Works

We’ve been building 3D-printed educational models of the BRZ rear multi-link suspension. You can tweak the arms, rotate the knuckle, and see exactly how the geometry works. Way faster than fiddling on a computer screen, and it translates directly to the car.

So far, we’ve focused on the rear suspension, but the front is on our radar, too. It’ll be trickier because of the MacPherson strut design, you’d need a strut tower and a sliding steering rack, but we can make it happen.

The BRZ rear setup has five control points on the subframe and four on the knuckle. We’ve numbered the arms on our model so you can follow along: upper control arm is one, lower is two, toe arm three, traction arm four, and the shock is five. Being able to move each arm individually shows how they affect camber, toe, bump steer, and even anti squat. For instance, the traction arm mostly controls knuckle rotation and bump steer, while the lower control arm changes both camber and toe. The toe arm fine tunes toe with a little camber effect, and the upper arm, when both legs are adjusted equally, mainly impacts camber.

We can also simulate different setups. For road racing, you typically increase rear camber while keeping axle angles safe, which usually means lengthening the lower control arm and adjusting the toe arm to maintain alignment. For drifting, you do almost the opposite. You reduce camber, keep the OEM upper arm, and shorten the lower control arm, toe arm, and traction arm to reposition the wheel properly. Cycling the suspension on the model lets you see exactly how the knuckle moves, how bump steer changes, and how wheel position shifts before touching your car.

One of the coolest things about these models is just how interactive they are. Each control arm has a toothed locking system with pinch collars, letting you lock arms in place and adjust incrementally. You can test extreme scenarios safely, exaggerate changes, and see how the knuckle reacts without ever touching the car. For shops, dynos, or pit setups, they’re a fantastic visual aid. You can experiment with adjustments on the model, then replicate them on the car.

Should we tackle the front suspension?

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