Swift Metric Springs

Springs are one of those components most people never think about, but we build around them. At HRD, we don’t treat springs as generic hardware you toss into a kit. They’re a critical part of how the car feels at 10/10ths and at 10 mph. That’s why we only use Swift Springs. Their engineering, material science, and consistency match the standard we hold for our own parts, and they give us the foundation we need to deliver true Dual Duty performance: podium-ready when pushed, civilized when you’re just driving home.

The core of Swift’s advantage is in the material and the way it’s formed. Their proprietary spring alloy allows them to achieve a given rate with fewer coils and more usable stroke compared to typical aftermarket springs. That translates into better control over body motion, more freedom for us to shape the damping curve, and less chance of coil bind under aggressive use. When we model and tune our damper valving, we can rely on the Swift spring to behave exactly as expected. Linear, predictable, and repeatable. That level of trust lets us push harder on performance without compromising durability.

Unsprung weight is another reason we’re all-in on Swift. Because their springs can achieve the same or higher rate with less material, they are often lighter than conventional alternatives. Dropping weight at the corners of the car is one of the most efficient ways to improve response, grip, and ride quality all at once. A lighter spring can move and react more quickly, which means the tire stays in better contact with the road over imperfections. On track, that shows up as better stability and confidence mid-corner; on the street, it shows up as a ride that feels surprisingly composed for how capable the setup is.

Longevity and consistency matter just as much as feel. Many lower-tier springs are fine for the first season, then quietly sag, lose rate, or become noisy as the material fatigues. That’s not acceptable for our philosophy. Swift’s material and manufacturing process give us springs that hold their free length and rate over time, even under heat cycles and real-world abuse. When we say a setup is engineered to be a long-term solution, that promise depends on every part in the system pulling its weight, literally. Swift is the only spring we trust to keep the car where we calibrated it, year after year.

Refinement is another area where Swift makes a difference. The way a spring transitions into and out of load, its small-bump behavior, its ability to manage high-frequency inputs all has a huge impact on NVH and driver confidence. Paired with our damper tuning, Swift springs allow us to deliver that “controlled without punishment” feel we’re known for. You get sharp responses, clean weight transfer, and stability under braking, without the brittle, choppy ride that often comes with generic “performance” springs. It’s a big part of why our kits feel so put-together in both daily driving and flat-out conditions.

We also care about process. Using Swift exclusively means every HRD design is built around a known, repeatable spring behavior. Rates are accurate, tolerances are tight, and production batches are consistent, which simplifies our development and lets us spend our time refining the driving experience instead of chasing variability in basic hardware. We’re not interested in saving a few dollars by swapping in whatever spring is cheapest this month. We’d rather lock in a partner that aligns with our values and build something we’re proud to put our name on.

In short, we only use Swift Springs because they let us engineer the kind of systems we believe in. They support our Dual Duty mission: lighter where it counts, stronger where it matters, and refined enough to live with every day. When you buy an HRD setup, you’re not just buying “a coilover with some springs on it.” You’re buying a package where every component, down to the coils themselves, has been chosen to meet a higher standard. Swift is the only spring that clears that bar for us.