Crown gear 28d. Sidewinder M50 16.5mm Procomp-RS Poly

The crown that makes a difference in your Sidewinder slot car transmission

The SC-1159R crown gear from Scaleauto is a 28-tooth transmission component, M50 module, made from Procomp-RS polyamide, Scaleauto's reference technical material for competition crown gears. With a diameter of ø16.5mm, it is designed for Sidewinder configurations — that is, with the motor positioned transversely to the rear axle — one of the most common setups in slot cars for tuning and competition.

Main features

• Number of teeth: 28
• Module: M50
• Diameter: ø16.5mm
• Material: Procomp-RS polyamide
• Compatible axle: 2.38mm
• Fixing: M2.5 screw
• Motor configuration: Sidewinder
• Reference: SC-1159R

Function and performance

The crown gear is one of the most critical elements of the transmission in a slot car: it directly affects the gear ratio, motor response, and smoothness of operation. A crown gear with excessive play or premature wear results in loss of efficiency and noise on track.

The Procomp-RS polyamide from Scaleauto combines lightness, wear resistance, and a low coefficient of friction. This means smooth meshing with the pinion, less vibration transmitted to the chassis, and greater durability under competitive demands. The M50 module is a widely adopted standard in the slot tuning universe, facilitating pairing with pinions of the same range.

Compatibility and installation

This crown gear is designed for 2.38mm axles, a common measurement in many competition chassis on the market. The fixing is done using an M2.5 screw, allowing for a firm tightening and clean disassembly during maintenance sessions or when changing the gear ratio by testing crowns with different numbers of teeth.

Before installation, it is advisable to check that the pinion installed on the motor is also of M50 module and that the axle is correctly aligned to ensure uniform meshing around the entire circumference of the crown. A slight misalignment can cause asymmetric wear and reduce the lifespan of the part.

Common mistakes when working with slot crown gears

• Mixing modules: combining an M50 crown with a pinion of a different module generates incorrect meshing, noise, and accelerated wear. Always check that both parts share the same module.
• Over-tightening the fixing screw: this can deform the crown or compromise concentricity. Tighten firmly but without forcing.
• Not checking lateral play: the crown should have a small controlled axial play. Too much adjustment can cause rubbing; too much play can lead to instability in meshing.
• Installing the crown without cleaning the axle: grease, dust, or machining burrs can hinder centering. Clean the axle before mounting.

Ideal for…

This crown gear is a solid choice for enthusiasts preparing slot cars for club competition or for those looking to optimise the transmission of their models on Sport track. It is also very useful as a maintenance spare to always have a crown in good condition on hand and avoid interruptions during practice or competition sessions.

Frequently asked questions

What does it mean that this crown is for Sidewinder configuration?

In a Sidewinder configuration, the motor is placed transversely to the rear axle, that is, parallel to it. This allows the crown to sit directly on the rear axle of the car, transmitting the motor pinion's movement in a very direct and efficient manner.

Is this crown compatible with any M50 module pinion?

In principle, yes, as long as the pinion is also of M50 module and designed for the same mounting configuration. Also, check that the distance between the motor and axle centres is correctly adjusted for optimal meshing.

What advantages does Procomp-RS polyamide offer over other materials?

Procomp-RS polyamide provides a good combination of lightness, mechanical strength, and low wear. Compared to metal crowns, it reduces meshing noise and better absorbs small alignment imperfections. It is the material that Scaleauto uses in its Procomp range crowns for competition applications.

Can I use this crown on a car with Inline or Anglewinder configuration?

This crown is specifically designed for Sidewinder. In Inline configuration (motor in line with the axle, perpendicular to it) or Anglewinder (motor at an angle to the axle), the transmission geometry is different and requires specific parts for each configuration. Check the Scaleauto catalogue to find the appropriate crown for your setup.

How often should I check or replace the crown?

It depends on usage and track conditions. In regular competition, it is advisable to visually inspect the crown in each session for wear on the tooth flanks or excessive play in meshing. Always having a spare like this in the workshop case avoids surprises at the worst moment.

The Scaleauto SC-1159R is a 28-tooth M50 module crown gear for Sidewinder slot car setups, featuring a ø16.5mm diameter and Procomp-RS polyamide construction. Designed for 2.38mm axles with M2.5 screw fixing, it delivers smooth meshing, low wear and reliable performance for club racing and slot car tuning enthusiasts.