9d Plastic Pinion

The bevel pinion that makes a difference in your drivetrain

When tuning a slot car, the transmission is one of the elements that most influences the final behaviour on the track. The 9-tooth Plastic Bevel Pinion from Policar (ref. PO-PPI429O20B) is a part designed for those who pay attention to every detail of the drivetrain: made of plastic, with a 9-tooth bevel geometry, a diameter of ø4.2mm, and specifically designed for 2mm axles.

Features and function

• Type: Plastic bevel pinion
• Number of teeth: 9t
• Diameter: ø4.2mm
• Compatible axle diameter: 2mm
• Reference: PO-PPI429O20B
• Manufacturer: Policar

The bevel geometry of this pinion allows the transmission of the motor's movement to the rear axle at a specific angle, which is common in configurations where the motor's position relative to the axle is neither completely parallel nor perpendicular. Its plastic construction reduces weight in the transmission and contributes to smoother rolling compared to metal parts in certain setups.

Compatibility and installation

This pinion is designed for 2mm diameter axles, a widely used measurement in slot cars from various brands and scales. Before installing any pinion, it is advisable to verify that the motor shaft diameter matches the specified size and that the pinion module is compatible with the crown gear it will work with, to ensure correct meshing without play.

The precise fit between pinion and crown is crucial: excessive distance causes power loss and noise; too tight a fit leads to premature wear and mechanical binding. We recommend checking the backlash (play between teeth) with a thin sheet of paper between both parts as a basic reference.

Common mistakes when installing bevel pinions

• Forcing the pinion onto a shaft of incorrect diameter, which can damage both the pinion and the motor shaft.
• Not properly aligning the working angle of the bevel pinion with the crown, resulting in uneven contact between teeth.
• Combining pinion and crown of different modules, which prevents smooth meshing regardless of the distance adjustment.

Frequently asked questions

What type of motor is this pinion suitable for?

This pinion is suitable for any motor with a 2mm diameter output shaft. This is a common size in many slot motors, but it is advisable to verify it before installation.

What advantage does a plastic pinion have over a metal one?

Plastic offers lower weight and, in many combinations, a quieter transmission. Conversely, it has lower wear resistance under very high loads. For regular use in clubs or at home tracks, the performance is more than sufficient.

What type of crown should be used with a bevel pinion?

A bevel pinion works with a bevel crown of the same module. The bevel geometry allows both parts to mesh at an angle between axes, something that is not possible with conventional straight pinions.

When should I replace the pinion?

When unusual noise is detected in the transmission, power loss occurs without apparent cause in the motor, or visible wear is observed on the flanks of the teeth when inspected with a magnifying glass or with the naked eye under good light.

The Policar PO-PPI429O20B is a 9-tooth plastic bevel pinion gear with a ø4.2mm diameter, compatible with 2mm motor shafts. An essential slot car drivetrain spare part for precise gear mesh setup, available at Ministry of Hobby.