Crown 31d. Sidewinder M50 ø16.5mm Procomp-RS polyamide for Shaft 2.38mm and Screw M2.5

The Scaleauto SC-1162R Crown Gear: Precision Transmission for Your Procomp-RS Sidewinder Setup

When searching for a reliable transmission system in a competitive slot car, every component matters. This 31-tooth crown gear from Scaleauto, part of the Procomp-RS series, is specifically designed for sidewinder configurations — that is, with the motor positioned transversely and parallel to the rear axle — and offers a consistent, repeatable, and easily adjustable gear ratio in the workshop.

Technical Features

• Teeth: 31d
• Module: M50
• Outer Diameter: ø16.5mm
• Material: Polyamide (PA)
• Axle Compatibility: 2.38mm
• Fixing: M2.5 screw
• Series: Procomp-RS
• Reference: SC-1162R

Function and Performance

Polyamide is a commonly chosen material for competitive slot crown gears due to its balance between rigidity, lightness, and ability to absorb small irregularities in the mesh without deteriorating. Compared to metal crowns, it reduces vibration transmission to the chassis and generates less noise during operation, which can translate into cleaner driving during long club sessions.

With 31 teeth and a module of 50, this crown is typically paired with smaller pinions to achieve gear ratios suited for tracks with medium or long straights, although the choice of the ideal pinion will always depend on the mounted motor, the type of circuit, and the driving style of each enthusiast.

Compatibility and Installation

Designed for a rear axle with a 2.38mm diameter — the standard in most Scaleauto Procomp-RS competition chassis — and fixed with an M2.5 screw, allowing for quick disassembly and replacements during preparation sessions or between heats. The screw fixing also facilitates precise alignment with the motor pinion, a critical aspect to minimize premature wear of both parts.

Before installation, it is advisable to ensure that the axle is perfectly clean and free of burrs in the seating area, and that the fixing screw is aligned with the flat plane of the axle if it has one. A crown poorly seated laterally is one of the most common causes of noise and loss of efficiency in the transmission.

Common Mistakes When Working with Polyamide Crowns

• Over-tightening the M2.5 screw: it can deform the seating and create eccentricity in the crown.
• Not checking the lateral play with the pinion before closing the chassis.
• Mixing modules: ensure that the motor pinion is also module 50 for correct meshing.
• Reusing a crown with visible wear on the tooth flanks: in competition, it is preferable to replace it in time.

Ideal for…

Preparers and enthusiasts who assemble or maintain Scaleauto Procomp-RS chassis in sidewinder configuration, whether for club competition, federated championships, or simply to maximise the performance of their car at home. The availability of specific spare parts like this crown is one of the recognised advantages of the Scaleauto range over other brands in the market.

Frequently Asked Questions

Is this crown compatible with chassis other than Procomp-RS?

It can be mounted on any chassis that uses a 2.38mm axle and allows for M2.5 screw fixing, provided that the motor pinion is also module 50. Always check the distance between the axle and motor centres before confirming compatibility.

What module should I use on the pinion for it to mesh correctly with this crown?

The module of the crown is M50 (0.5mm). The motor pinion must necessarily be of the same module to ensure correct meshing and avoid accelerated wear.

Is polyamide suitable for competition or just for recreational use?

Polyamide is perfectly valid for competition. It is the predominant material in high-end crowns due to its lightness, low noise level, and good wear resistance. Many club and federated competition preparers prefer it over metal alternatives.

What pinions pair well with this crown for a medium-speed track?

For a ratio suited to medium-high speed tracks, 31-tooth crowns are typically combined with pinions ranging from 8 to 11 teeth, depending on the motor. However, the optimal ratio depends on the torque and RPM of the specific motor you use, so we recommend testing on track.

How do I know when to replace the crown?

The most common signs are: irregular noise in the transmission, excessive play in the mesh that is not corrected by repositioning the crown, or visible wear on the flanks or tips of the teeth. In competition, it is common to check the condition of the crown after each intense track day.

The Scaleauto SC-1162R is a 31-tooth sidewinder crown gear, module 50, ø16.5mm, made in polyamide and designed for 2.38mm axles with M2.5 screw fixing. Part of the Procomp-RS range, it delivers smooth, precise power transmission for slot car racing and is a go-to upgrade or replacement part for competitive club racers and serious hobbyists building or maintaining Scaleauto sidewinder setups.