Crown gear in line 25z

25-tooth inline crown gear for 2.38 mm axle — Avant Slot AV20632

When working with an inline configuration —longitudinal motor in line with the rear axle— the transmission is a critical point. The crown gear is the component that receives the push from the pinion and transforms it into traction, and a correct choice of the number of teeth can make the difference between overly aggressive acceleration and a well-utilised progression on each straight section.

Technical specifications

• Number of teeth: 25z
• Compatible axle diameter: 2.38 mm
• Mounting system: M2.5 screw (included)
• Configuration: inline (motor in line with the rear axle)
• Reference: AV20632
• Manufacturer: Avant Slot

Function and performance

A 25-tooth crown gear is positioned within a gear ratio range that balances top speed and torque. Combined with the appropriate pinion, it allows for adjusting the car's response to different types of circuits: more revs on fast tracks or more torque on technical circuits with many slow corners.

The M2.5 screw mounting ensures that the crown gear does not migrate on the axle under the vibrations typical of competition. Mechanical fixation is especially valued in club preparations, where the repeatability of assembly is fundamental.

Compatibility and installation

This crown gear is designed for 2.38 mm axles, a common measurement in many competition slot car chassis. Before installing it, it is advisable to verify that the car's axle matches this measurement exactly to ensure a fit without play or excessive tension.

The installation process is straightforward: insert the crown gear onto the axle to the desired position and tighten the included M2.5 screw. We recommend checking the alignment with the pinion before final tightening to avoid vibrations or premature wear of the teeth.

Common mistakes

• Installing the crown gear without checking the alignment with the pinion: this generates noise and accelerated wear.
• Over-tightening the screw can deform the crown gear or mark the axle, complicating future adjustments.
• Confusing the axle diameter: the AV20632 crown gear is for 2.38 mm; using it on an axle of a different size compromises the transmission.

Ideal for…

Tuners and enthusiasts who assemble or set up slot cars with inline motors and seek a reliable spare part with mechanical fixation via screw. It is also practical for those experimenting with different gear ratios and needing to change the crown gear quickly between sessions.

Frequently asked questions

What is the difference between an inline configuration and a sidewinder?

In an inline setup, the motor is placed longitudinally, in line with the rear axle, which lowers the car's centre of gravity. In a sidewinder, the motor is positioned transversely, parallel to the axle. Each configuration requires its own specific crown gear and pinion.

Is the M2.5 screw included?

Yes, the AV20632 crown gear includes the necessary M2.5 screw for mounting, so it is not necessary to purchase it separately.

Which pinions is this crown gear compatible with?

Compatibility depends on the tooth module. Avant Slot offers specific pinions for their inline crown gears; we recommend consulting the brand's catalogue or contacting us to ensure that the pinion-crown combination is correct for your setup.

Can I use this crown gear on an anglewinder chassis?

Inline and anglewinder crown gears are not interchangeable, as the tooth geometry and working angle are different. This AV20632 crown gear is specifically designed for inline configurations.

When should I change the crown gear?

When visible wear on the teeth is observed, excessive play between crown and pinion, or unusual noise during operation. In competition setups, it is common to check it periodically along with the rest of the transmission.

The Avant Slot AV20632 is a 25-tooth inline crown gear for 2.38 mm axles, secured with an included M2.5 screw. Designed for inline motor setups in slot car racing, it offers a reliable and precise mechanical fit. A key spare part for slot car tuning, club racing preparation, and driveline optimisation in 1/32 scale slot cars.