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The mass dampers (Japanese: マスダンパー, Masu Dampaa) are a type of Grade-Up Parts that can improve a Mini 4WD car's stability.

What is mass damper

The mass dampers are a type of Shock absorb parts, used to absorbs the shocks cause by having the car land onto the road surface.

A freely moving weight, held into one place by one or more long screws, starts floating once the car jumped. When the car lands onto the track, the weight will quickly move down and push against the car, absorbing the landing impact shocks and prevents the car from rebound. The weight, having absorbed the shocks from the car, moves up to disperse the kinetic energy before moving back down.

The mass dampers, along with other Tamiya GUPs, can be used to create the more advanced mass damper setup.

Type of movable weights

There are 11 types of movable weights, and comes in various sizes and shapes. All of them were made of brass.

  • Extra small type: Measured 7mm in diameter and 5.5mm in height. Weighted at around 1.5g. Rotatable.
  • Adjust type: Weighted at around 2.5g. Usually used to adjust the mass damper's strength. Rotatable.
  • Tall small type: Measured 7mm in diameter and 11.5mm in height. Weighted at around 3g. Rotatable.
  • Bowl type: Weighted at around 3.4g. Rotatable.
  • Short square type: Measured 6 x 6 x 14mm. Weighted at around 3.6g.
  • Cylinder type: Weighted at around 4.2g. Rotatable.
  • Normal type: Weighted at around 4.7g. Rotatable.
  • Thick short square type: Measured 8 x 8 x 14mm. Weighted at around 6.6g.
  • Square type: Measured 6 x 6 x 32mm. Weighted at around 8.3g.
  • Heavy type: Weighted at around 8.8g. Rotatable.
  • Thick square type: Measured 8 x 8 x 32mm. Weighted at around 14.9g.

It should be noted that the square type ones need two or more screws to hold them into one place.

What not to do when installing the mass damper

Due to heavy nature of the mass dampers, it can easily disturbs the car's center-of-gravity if not done right. As such, it is always recommended to avoids installing the mass dampers at higher position, as doing so will put the car at risk of being coursed out during cornering.

In race regulation

In the race regulation, Square type mass damper(s) (held into one place(s) by two or more screws) are always placed within the width of the roller screws to avoid being touching the fence. Only the rotatable mass dampers can be placed anywhere, as long as they were within the maximum length and width that the regulation allowed.