25Z angle crown gear

The Slot.it FLAT anglewinder crown gear for those who know what they are looking for

The SIGA1525PL crown gear is one of the most specific transmission parts in the Slot.it catalogue: 25 teeth, designed for a 2.38 mm (3/32) axle, and mandatory pairing with a 6.75 mm diameter pinion. Its orange colour is not just aesthetic: it facilitates immediate identification among the other crown gears in the drawer.

Technical specifications

• Number of teeth: 25 Z
• Compatible axle diameter: 2.38 mm (3/32)
• Required pinion: 6.75 mm diameter
• Configuration: Anglewinder, special FLAT
• Identification colour: orange
• Reference: SIGA1525PL

Function and performance

In an anglewinder configuration, the motor is positioned at an angle to the rear axle, allowing for a lower centre of gravity and more internal space in the chassis. The FLAT variant takes this concept a step further: the motor-crown assembly is almost flush with the bottom of the chassis, minimising overall height and improving corner stability.

With 25 teeth, this crown gear offers a gear ratio suited for circuits with medium to long straights where top speed is sought without excessively sacrificing acceleration response. The enthusiast preparing their car for Sport track —the system used by Slot.it in their own chassis— will find this crown gear a solid starting point for adjusting the gearing to their motor and track.

Compatibility and installation

Before installing this crown gear, it is advisable to check two critical points:

1. That the rear axle of the chassis is 2.38 mm (3/32). This is the standard size in most Slot.it chassis, but not all; some models use a reinforced 3/32 axle or special configurations.
2. That the pinion installed on the motor has exactly 6.75 mm outer diameter. A pinion of a different size will cause incorrect spacing, excessive noise, and premature wear of both parts.

Adjusting the backlash (play between crown and pinion) is crucial: too tight generates friction and heat; too loose introduces vibration and loss of traction. The usual method is to place a cigarette paper or a calibrated sheet between both parts during installation.

Common mistakes

• Using this crown gear with a pinion of a diameter different from 6.75 mm. The result is incorrect tooth contact that accelerates wear.
• Installing the crown gear on a chassis with a 3 mm axle believing it "fits the same". The difference in hundredths causes lateral play and loss of alignment.
• Not checking the perpendicularity of the crown gear to the axle once tightened. A small angular deviation translates into vibration at high speed.

Ideal for…

This crown gear is designed for drivers preparing anglewinder chassis in FLAT configuration with Slot.it components, for both club use and regulated category championships where precision transmissions are employed. It is also the direct replacement option for Slot.it chassis that come factory-fitted with this same reference.

Frequently asked questions

Can I use this crown gear in a sidewinder configuration?

It is not designed for that. The FLAT geometry of this crown gear is specific for anglewinder mounts. In a sidewinder, the motor shaft is parallel to the rear axle and requires crown gears with a different geometry.

What pinion should I use with the SIGA1525PL?

According to Slot.it specifications, you need a pinion with 6.75 mm outer diameter. Check the Slot.it pinion catalogue to find the exact reference based on the number of teeth and the axle of your motor.

Is it compatible with chassis from other brands?

It can be mounted on any FLAT anglewinder chassis that uses a 2.38 mm (3/32) axle and has a motor with a 6.75 mm pinion. Compatibility depends on those two measurements, not on the brand of the chassis.

Why is it orange?

Slot.it uses a colour coding system for their crown gears to quickly identify the number of teeth and the type of mount. Orange corresponds to this 25-tooth reference in FLAT version, facilitating stock management of spare parts at the workbench.

When should I change the crown gear?

When visible wear is observed on the flanks of the teeth, metallic noise during operation, or excessive play that cannot be corrected by adjusting the spacing. In competition, it is common to check it along with the pinion after several intense racing sessions.

The Slot.it SIGA1525PL is a 25-tooth anglewinder FLAT crown gear designed for 2.38 mm (3/32) axles, requiring a 6.75 mm pinion. A precision slot car replacement part ideal for anglewinder FLAT chassis setups, club racing, and regulated championship categories. Compatible with Slot.it Sport track systems and optimized for low-profile, high-stability configurations.