Breaking Down BMW’s 5-Link Rear Suspension

We just finished our BMW 5-link rear suspension 3D display, and I’m really excited to share it. The main goal with this display was to help people actually see how the rear five-link works, and the best way to do that was by exaggerating the length and adjustment of each control arm. This isn’t a precision measurement tool for your car, but it’s perfect for understanding what changing a control arm really does — how it affects squat, bump steer, camber gain, and the overall kinematics of the OEM suspension. Plus, it’s just fun to play with.

One thing I added at the last minute was the shock mount. It’s important to have as a reference since that’s where the suspension goes, and we replicated the motion ratio and location pretty accurately. That said, it’s more fun to play with the display without the shock attached because the suspension cycles more easily. The whole thing comes apart really easily anyway, so you can attach or remove the shock depending on what you want to explore.

When you start moving the control arms, it’s really eye-opening. BMWs only have two adjustable arms from the factory: the lower control arm, which primarily controls camber, and the toe arm, which mostly handles toe. On our display, adjusting the lower arm not only changes camber but also affects toe and wheelbase. Exaggerating it makes it easy to see. Adjusting the toe arm gives you mostly toe changes, and you can even see why this is the arm that frequently fails in drifting setups, since it carries so much force while keeping the alignment under control.

The display also includes the upper control arm, traction arm, lower trailing arm, and of course the toe and lower control arms, all adjustable. Tweaking any of these shows how the rear suspension works together as a system. Adjusting just one arm can create unexpected rotations, but adjusting pairs of arms together gives a more linear, predictable result. You can experiment with camber gain, toe gain, and anti-squat percentages in real time, and see how rotating the knuckle or shortening the traction arm changes the rear suspension’s behavior under compression. It’s a hands-on way to understand the interplay of all these links, and how even small changes affect the car.

We made it to scale, so each notch in the display represents an eighth of an inch. That means if you scale your adjustments back up to the real car, you can actually see how the movement would translate — a really neat way to visualize the suspension geometry without taking anything apart on your car.

The display is available on our website for download. You can print it yourself, though you’ll need to buy 9 mm balls and M4 screws to assemble it. Or, if you want a fully assembled version, we offer that too. Either way, it’s a blast to use and a huge help for anyone trying to understand BMW rear suspension setups. This model applies to nearly every BMW from around 2006 onward, including GT4 race cars, and it also works as a reference for other cars that use a similar five-link layout, like some Genesis and Mercedes models.

If you’ve picked up the BMW 5-link display and tried it out, we’d love to hear how it’s helped you understand your setup. It’s one thing to read about suspension geometry, but seeing it and moving it yourself makes all the difference.