Hyperco 3.75″ I.D. x 18″ Free Length Coilover Spring, G Series, 250-400 lbs/in Rate (Choose Rate)
$177.00
Hyperco 3.75″ I.D. x 18″ Free Length Coilover Springs — G Series

Hyperco high-performance G-series coilover springs in a 3.75″ (95.2 mm) inside diameter and 18″ (457.2 mm) free length. Precision cold-wound from high-tensile chrome-silicon wire, heat-treated, preset and 100% rate-tested, so the printed rate is the delivered rate. Lighter weight and more usable deflection than comparable springs, made in the USA.
Select your spring rate from the drop-down. Every spring in this listing shares the same 3.75″ I.D. and 18″ free length; only the rate and its associated deflection, load and coil dimensions change. All dimensions are shown in both inches and millimeters.
Rate Chart
| SKU | Rate (lbs/in) | Max Deflection | Max Load (lb) | Outside Dia. | Solid Height | Color |
|---|---|---|---|---|---|---|
| 1818G0250 | 250 | 12.357″ (313.9 mm) | 3089 | 5.021″ (127.5 mm) | 5.643″ (143.3 mm) | Silver |
| 1818G0300 | 300 | 12.15″ (308.6 mm) | 3645 | 5.016″ (127.4 mm) | 5.85″ (148.6 mm) | Silver |
| 1818G0350 | 350 | 11.706″ (297.3 mm) | 4097 | 5.08″ (129.0 mm) | 6.294″ (159.9 mm) | Silver |
| 1818G0400 | 400 | 11.472″ (291.4 mm) | 4589 | 5.284″ (134.2 mm) | 6.528″ (165.8 mm) | Silver |
Specifications
- Inside diameter: 3.75″ (95.2 mm)
- Free length: 18″ (457.2 mm)
- Series: G
- Rate range: 250–400 lbs/in
- Finish: Silver powder-coat
- 100% rate-tested, made in the USA
- Sold individually.






