Sidewinder crown gear 37t

The NSR sidewinder crown that fits where you need it

The Sidewinder Crown 37t (NSR6137) is a transmission component from NSR designed for sidewinder configuration setups, where the motor operates parallel to the rear axle. With 37 teeth, a shaft of 2.38 mm, and a diameter of 18.5 mm, it fits directly into the most common platforms in the hobby without the need for modifications.

Technical specifications

• Number of teeth: 37t
• Shaft diameter: 2.38 mm
• Crown diameter: 18.5 mm
• Configuration: Sidewinder (motor parallel to the rear axle)
• Compatibility: Scalextric, Fly and Sloter

Function and performance

In a sidewinder configuration, the crown is the element that closes the transmission circuit between the motor pinion and the rear axle. A crown that is poorly adjusted in terms of the number of teeth or shaft diameter directly results in play, vibrations, and premature wear. The NSR6137 is machined with the tolerance that characterises NSR, ensuring a clean mesh and efficient transmission from the first laps.

The 37 teeth place it in a development range suitable for medium-high speed tracks, especially when combined with pinions of between 9 and 12 teeth. The resulting gear ratio allows for good acceleration without sacrificing top speed on the straights.

Compatibilities

This crown is intended for chassis and setups that use a rear axle of 2.38 mm, the most common diameter in Scalextric, Fly, and Sloter cars. If you have doubts about whether it will fit your specific platform, always check the axle diameter before installation: it is the critical data to ensure a fit without play or interference.

Installation and preparation

The installation is straightforward if the axle is clean and free of old grease or dirt. We recommend checking the condition of the pinion before installing a new crown: if the pinion shows irregular wear, the new crown will quickly exhibit that wear. A minimal amount of special gear grease at the pinion-crown contact point is sufficient; excess lubricant only attracts dust and penalises the transmission.

After installation, check the backlash (play between pinion and crown) with the motor in its final position. It should be barely perceptible to the touch: neither so tight that it causes rubbing, nor so loose that it results in vibration while running.

Common mistakes

• Installing the crown on an axle of a different diameter than indicated (2.38 mm). The result is always play or inability to mount.
• Not checking the wear of the pinion before changing the crown.
• Over-lubricating: a drop at the contact point is more than sufficient.
• Not checking the lateral alignment between pinion and crown after installation, which causes asymmetric wear and noise.

Frequently asked questions

What is the difference between a sidewinder crown and an inline one?

The difference lies in the orientation of the motor relative to the rear axle. In a sidewinder configuration, the motor is parallel to the axle, and the crown receives the rotation directly from the lateral pinion of the motor. In an inline configuration, the motor is perpendicular (in line) to the rear axle. The crowns are not interchangeable between both configurations without adapting the entire transmission set.

Is this crown compatible with all Scalextric cars?

Compatibility depends on the diameter of the car's rear axle. This crown is designed for 2.38 mm axles, which is the usual diameter in many Scalextric, Fly, and Sloter cars, but we recommend verifying the specifications of your specific model before ordering.

What pinion works best with this 37-tooth crown?

It depends on the motor and the type of track. For medium-speed tracks with technical curves, a ratio around 10/37 or 11/37 usually works well. For long straights and fast tracks, you can try a slightly larger pinion. The ideal is to adjust the ratio according to the motor you use and the characteristics of the circuit.

Do I need special tools to install it?

Special tools are not essential, but a crown puller and a backlash gauge make the job much easier and prevent damage to the part during installation. At Ministry of Hobby, you will find the appropriate preparation tools for this type of task.

How often should I check or change the crown?

It depends on usage and proper lubrication. With regular club use, a visual check every few sessions is sufficient. If you notice noise in the transmission, unusual vibration, or loss of speed, check the condition of the mesh before assuming the problem lies in another component.

The NSR6137 is a 37-tooth sidewinder crown gear for 2.38mm axles, with an 18.5mm diameter. Compatible with Scalextric, Fly and Sloter slot car platforms, it delivers clean and efficient power transmission for sidewinder motor configurations. A reliable NSR replacement part for club racing and home track enthusiasts looking for precise gear mesh and consistent performance.