True Rear vs OEM Rear on 350Z / 370Z / G35 / G37 (What’s the Difference?)

OEM-Style Rear (Divorced Spring + Shock)

The factory-style rear suspension on these platforms uses a separate rear spring and rear shock (often called a “divorced” setup). The spring sits in its own location, and the shock mounts separately.

• Pros: retains factory layout, typically straightforward packaging
• Considerations: rear tuning changes can be less direct, and rear wheel control depends heavily on how the shock and spring interact through the OEM geometry. Rear ride height adjustability range is limited, and it is more work to make adjustments.

True Rear Coilover (Spring Mounted on the Damper)

A true rear coilover places the rear spring directly on the rear damper, so the spring and shock work together as a single unit at the wheel.

• Pros: more direct rear tuning, ride height adjustability range is much larger.  Adjustments are easier to make. A more “connected” rear feel under load. Weight savings by deleting the spring bucket. More toe adjustability is achievable since the spring perch is removed from the toe arm. 
• Considerations: requires proper design/engineering for the rear mounts and travel to work correctly

Important Note: Motion Ratio & Why Rear Spring Rates Look “Different”

The motion ratio (how much the spring compresses versus how much the wheel moves) is different between the two layouts. Because of that, the spring rate numbers you see can look very different even when the car’s effective wheel rate is the same.

In general terms, wheel rate is proportional to: Wheel Rate ≈ Spring Rate × (Motion Ratio)². When the motion ratio is lower (the spring moves less for a given amount of wheel travel), you need a stiffer spring to achieve the same wheel rate.

On these platforms, an OEM-style divorced rear spring commonly ends up requiring roughly ~2.2× stiffer spring rates (at the spring) compared to a true rear coilover setup to achieve a similar effective wheel rate. So while the spring rate number is higher on an OEM-style rear, the at-the-wheel stiffness can be essentially the same when the setup is designed correctly.

Why It Matters (Street, Track, Drift)

Street / Canyon

A well-designed true rear setup can feel more controlled and predictable over repeated load changes, especially when paired with damping that matches the spring rate.

Track / Time Attack / HPDE

The biggest benefit is rear consistency—braking zones, mid-corner load, and power-on corner exit feel more repeatable when rear wheel control is stable session-to-session.

Drift

Drift drivers often want a rear that stays consistent through throttle application and transitions. A true rear coilover can make rear behavior easier to tune and repeat.

Quick Rule of Thumb

If you mainly drive on the street, either layout can work great with the right damping and alignment. If you care about repeatability at the limit (track or drift), a true rear coilover is often preferred—assuming it’s engineered and tuned correctly.

FAQ

Does “true rear” automatically make the car faster?

Not by itself. The advantage comes from how well the system is designed and tuned. Spring rate, damping, alignment, and tires still matter most.

Can I use a true rear setup on street and track?

Yes—many dual-duty cars run true rear coilovers successfully. The key is matching spring rates and damping to your use case and road conditions.

Is OEM-style rear “bad”?

Not at all. The OEM-style layout can work extremely well when properly tuned. True rear simply changes how the spring and damper are packaged and tuned.