Sidewinder Extralight ERGAL Crown 31 teeth 16.8 mm for Hypercar

NSR Precision for the Transverse Transmission of Your Hypercar

Within the NSR catalogue of transverse crowns, the Extralight series occupies the highest tier in terms of reducing rotating mass. This crown with 31 teeth and 16.8 mm in diameter, reference NSR5931, is specifically designed for Sidewinder configurations —motor positioned parallel to the rear axle— in the Hypercar chassis, and reflects the level of demand that NSR applies to each transmission component.

Function and Performance

In a Sidewinder transmission, the crown is the part that directly receives the torque from the pinion and transfers it to the rear axle. The lower its mass, the less inertia the motor must overcome during each acceleration. The NSR Extralight line addresses this principle radically: starting from solid ERGAL —high-strength aerospace aluminium— and machining each piece using CNC, a component with minimal weight is achieved without sacrificing rigidity or dimensional precision.

The practical result on track is immediate: the car's response when applying throttle from the apex of the corner is more lively, the motor operates with less load, and the power delivery feels cleaner and more progressive. For those who adjust gear ratios based on specific layouts, having a 31-tooth crown in the toolbox allows for exploring long ratios while maintaining contained inertia.

Materials and Manufacturing

• Anodised ERGAL: the anodising surface treatment is not just aesthetic; it generates a layer of aluminium oxide that hardens the surface of the teeth and protects against abrasion caused by continuous contact with the pinion.
• CNC Machining: ensures very tight tolerances in the profile of each tooth, resulting in a smooth mesh, without play or hard spots that increase consumption or generate unnecessary heat.
• Pitch and Diameter: 31 teeth with 16.8 mm outer diameter, the usual parameters of the NSR range for Hypercar chassis in transverse configuration.

Compatibility

This crown is designed to fit the NSR Hypercar chassis with Sidewinder motorisation. To achieve the best possible gearing, NSR recommends pairing it with pinions from the 71XX series, designed to work in harmony with the tooth profile of these Extralight crowns. Using pinions from other sources may compromise the smoothness of the transmission and accelerate the wear of both parts.

Installation and Preparation

Before installing the crown, it is advisable to clean the rear axle with a dry cloth to ensure a proper fit. Check that the crown-pinion alignment is parallel and that the spacing between teeth does not cause excessive tightness or lateral play. A light application of specific slot transmission lubricant on the tooth flanks, applied sparingly, completes the setup. Periodically checking the wear of the teeth in the contact area with the pinion significantly extends the lifespan of the assembly.

Common Mistakes

• Mixing Extralight crowns with standard plastic pinions: the difference in hardness between anodised ERGAL and certain plastics can lead to asymmetric wear. Always use the combination recommended by NSR.
• Over-tightening the fixing screw: ERGAL is strong, but excessive tightening torque can deform the housing. Adjust firmly but without forcing.
• Ignoring lateral alignment: even a small misalignment between crown and pinion introduces vibrations that negate part of the benefit of the ultralight construction.

Frequently Asked Questions

How does the Extralight line differ from NSR's standard crowns?

The Extralight line uses CNC-machined ERGAL instead of technical plastics or heavier metals. The result is a significantly lighter piece, which reduces the inertia of the rear axle and improves acceleration, especially on layouts with many chicanes and short-radius corners.

Is this crown compatible with other NSR chassis apart from the Hypercar?

The declared compatibility is for the Hypercar chassis in Sidewinder configuration. Before mounting it on another NSR chassis, it is advisable to verify that the diameter and pitch of 16.8 mm fit correctly with the available housing and pinion.

Which pinions should I use with this crown?

NSR recommends the pinions from the 71XX series, optimised to work with the tooth profile of the Extralight crowns. This combination ensures the smoothest mesh and the least possible wear.

Does anodising affect the dimensions of the crown?

The anodising process adds an extremely thin layer of oxide (on the order of microns), so it does not appreciably alter the machined dimensions. CNC tolerances remain intact.

When is it advisable to choose a 31-tooth crown over other options in the range?

A 31-tooth crown offers a relatively long ratio, suitable for high-speed layouts or motors with high torque. In technical circuits with many slow corners, a crown with more teeth may be preferable to gain traction on corner exit. Fine-tuning always depends on the motor, pinion, and characteristics of the layout.

Does it require special maintenance?

Periodically check the condition of the teeth and reapply a small amount of specific slot transmission lubricant. Clean off any old lubricant residue before each application. No extraordinary maintenance is required beyond the usual for transmission components.

The NSR Sidewinder Extralight crown, 31 teeth and 16.8 mm, reference NSR5931, is a top-tier slot car gear upgrade for the Hypercar chassis. CNC-machined from anodised ERGAL aluminium, it delivers reduced rotational inertia, sharper acceleration response and long-lasting durability. Designed for sidewinder motor layouts, it pairs perfectly with NSR 71XX series pinions for smooth, precise power transmission. An essential performance part for competitive 1/32 slot racing enthusiasts looking to fine-tune their drivetrain setup.