Mini 4WD tuning mass block 9g M4WD-39/BL by 3Racing  [M4WD-39/BL]

Compact 9g cuboid mass damper M4WD-39/BL for Mini 4WD

The M4WD-39/BL arrives as a compact cuboid mass damper in a black finish and is rated at 9 grams. It is an aftermarket mass block suited to Mini 4WD bodies and frames when small, intentional weight additions are required. The piece is supplied without mounting hardware, so how it is fixed will depend on the chassis and the builder's method.

Racers and hobbyists use the block to tweak static balance and distribute mass locally rather than expecting a standalone power improvement. Its actual impact is shaped by chassis layout, roller positions, and the full setup. It is most useful on setups where incremental mass shifts are part of broader tuning work.

Fitment checklist: inspect internal clearance under the body, watch for interference with rollers or guide stays, and choose a secure mounting approach before permanent attachment. The part is listed for Mini 4WD; confirm compatibility with your specific chassis.