Mugen rates its 1/8 off-road springs by wire diameter and turn count rather than lb/in — within a family, fewer turns means a stiffer spring. The springs below fit the MBX8R, MBX8R ECO, MBX8, and MBX8 ECO (Mugen lists fitment as X8R/8RE/8/8E), and every one links to that exact part at AMain. Softest to stiffest in each table.
Front Springs — 70mm, 1.6 mm Wire
| Spring | Wire × turns | Part # |
|---|---|---|
| X-Soft | 1.6 mm × 9.5T | #E2515 |
| Soft | 1.6 mm × 9.25T | #E2516 |
| Medium | 1.6 mm × 9.0T | #E2517 |
| Hard | 1.6 mm × 8.75T | #E2518 |
Front Springs — 70mm, 1.5 mm Wire
The older 1.5 mm-wire family fits the same 70 mm front shocks; at comparable labels it runs slightly softer than the 1.6 mm series.
| Spring | Wire × turns | Part # |
|---|---|---|
| Soft | 1.5 mm × 8.25T | #E2507 |
| Medium | 1.5 mm × 8.0T | #E2508 |
| Hard | 1.5 mm × 7.75T | #E2509 |
| X-Hard | 1.5 mm × 7.5T | #E2510 |
Rear Springs — Big Bore, 1.5 mm Wire
| Spring | Wire × turns | Part # |
|---|---|---|
| Soft | 1.5 mm × 8.75T | #E0582 |
| Medium | 1.5 mm × 8.5T | #E0575 |
| Hard | 1.5 mm × 8.25T | #E0576 |
| X-Hard | 1.5 mm × 8.0T | #E0577 |
| XX-Hard | 1.5 mm × 7.75T | #E0578 |
Fitment Notes
The 70 mm front springs also fit the MBX8T/MBX8TR truggies (Mugen lists X8TR/RE/8T/E), but the truggies use their own rear springs (E2581 series) — the big-bore rears above are the buggy fitment. Older big-bore front springs (E0573/E0574/E0581) belong to the MBX6/MBX7 generation and are not part of the current 70 mm lineup.
Other 1/8 Off-Road Spring Charts
Running something else? See the Kyosho MP10 & MP11 spring chart or the Team Associated 1/8 spring chart.
Specifications from Mugen Seiki's official part listings. Some links above are affiliate links that support the site.
