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.
MBX8 & MBX8R — Front, 70 mm (1.6 mm wire)
| Rating | Wire (mm) | Turns | Part # |
|---|---|---|---|
| X-Soft | 1.6 | 9.5 | #E2515 |
| Soft | 1.6 | 9.25 | #E2516 |
| Medium | 1.6 | 9.0 | #E2517 |
| Hard | 1.6 | 8.75 | #E2518 |
MBX8 & MBX8R — Front, 70 mm (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.
| Rating | Wire (mm) | Turns | Part # |
|---|---|---|---|
| Soft | 1.5 | 8.25 | #E2507 |
| Medium | 1.5 | 8.0 | #E2508 |
| Hard | 1.5 | 7.75 | #E2509 |
| X-Hard | 1.5 | 7.5 | #E2510 |
MBX8 & MBX8R — Rear, Big Bore (1.5 mm wire)
| Rating | Wire (mm) | Turns | Part # |
|---|---|---|---|
| Soft | 1.5 | 8.75 | #E0582 |
| Medium | 1.5 | 8.5 | #E0575 |
| Hard | 1.5 | 8.25 | #E0576 |
| X-Hard | 1.5 | 8.0 | #E0577 |
| XX-Hard | 1.5 | 7.75 | #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.
