Crown 42 D. M50 p/axle 3mm. New Racing Transversal

Transmission tuned with the Sigma 42D M50 crown gear for sidewinder configuration in 1/24

Within the range of transmission spare parts from Sigma, this 42-tooth crown gear, module 50 and hole for 3 mm axle is specifically designed for motors in sidewinder configuration —that is, with the motor positioned parallel to the rear axle—. The reference includes the designation New Racing Transversal, confirming its orientation towards competitive setups in 1/24 scale.

Function and performance

The crown gear is the transmission element that receives the motion from the pinion attached to the motor shaft and transfers it to the rear drive axle. With 42 teeth, a relatively long gear ratio is achieved: the car develops more top speed at the cost of a somewhat more progressive acceleration. It is a common choice on fast tracks, with long straights or in categories where maximum speed takes precedence over corner exit.

The module 50 (M50) determines the size of the teeth and their pitch. It is essential that both the crown gear and the pinion share the same module to ensure proper meshing, without play or interference that could cause premature wear or noise in the transmission.

Compatibility and mounting

The central hole is sized for 3 mm axles, the most widely used standard in 1/24 scale. Before mounting, it is advisable to check:

• That the motor pinion is also module 50.
• That the centre distance (motor–rear axle) on your chassis is compatible with the outer diameter of this 42-tooth crown gear.
• That the rear axle is 3 mm in diameter.
• The sidewinder orientation of the motor in the chassis, as this crown gear is designed for that arrangement.

Mounting and preparation

To achieve the best performance from the transmission:

1. Clean the rear axle before installing the crown gear to prevent lubricant residue from hindering a firm fit.
2. Check the backlash between the pinion and crown gear: it should be minimal but present, never tight.
3. Once mounted, apply a drop of specific slot transmission lubricant to the teeth; avoid excess to prevent contaminating the tyres.
4. Verify the centring of the crown gear relative to the pinion around the entire axle rotation to rule out eccentricities.

Common mistakes

• Mixing modules: mounting an M50 crown gear with a pinion of a different module causes poor meshing and rapid wear.
• Over-tightening: if the crown gear is locked onto the axle without the possibility of micro-adjustment, the heat generated during racing can expand the assembly and create stresses.
• Not checking the centre distance: in rigid or tightly measured chassis, a 42-tooth crown gear can interfere with other components if not checked before mounting.

Frequently asked questions

Which pinions is this crown gear compatible with?

With any pinion of module 50 (M50). The number of teeth on the pinion will determine the final gear ratio; consult the gear ratio tables to find the combination that best suits your track and category.

Is it valid for any motor configuration?

It is designed for sidewinder setups (motor parallel to the rear axle). In inline or anglewinder configurations, the gear geometry may not be suitable, depending on the chassis.

What is the difference between using 42 teeth and a crown gear with fewer teeth?

With a higher number of teeth on the crown gear, there is greater reduction: more top speed and smoother acceleration. A crown gear with fewer teeth offers more push and better corner exit, but limits maximum speed. The choice depends on the layout and regulations of your category.

Is the 3 mm hole standard in 1/24 scale?

Yes, the 3 mm axle is the most common diameter in 1/24 scale. Nevertheless, always check the measurements of your chassis before placing the order.

Do I need any special tools to mount it?

Generally, a crown gear puller and a pressure tool for mounting are sufficient. Avoid striking directly on the crown gear to prevent damaging the teeth or deforming the central hole.

The Sigma 42-tooth M50 crown gear for 3 mm axle is a precision transmission component designed for 1/24 scale sidewinder slot car setups. With 42 teeth and M50 module, it delivers a long gear ratio ideal for high-speed tracks. Compatible with standard 3 mm rear axles, it is a reliable upgrade or replacement part for competitive slot racing in 1/24 scale.