12-tooth 7mm ergal pinion

The Slot.it ergal pinion: lightness and precision for the transmission that makes a difference

Within Slot.it's transmission catalogue, ergal pinions hold a prominent place among tuners looking to reduce weight in moving parts without sacrificing an ounce of reliability. This 12-tooth and 7 mm pinion (reference SIPI7012E) is a small component but has a significant impact on the car's behaviour.

Function and performance

The pinion is the direct link between the motor and the crown gear: it transmits power from the motor shaft to the drivetrain. The lower its mass, the less inertia it accumulates, resulting in a more agile response from the car to changes in acceleration. The use of ergal —a high-strength aluminium alloy commonly found in competition components— allows exactly that: to reduce weight without compromising the integrity of the tooth or the concentricity of the assembly.

With 12 teeth, this pinion favours longer gear ratios when combined with smaller crown gears, translating to higher top speeds on fast circuits or long straights.

Compatibility and installation

Designed for 2 mm motor shafts, the 7 mm outer diameter places it within the standard range of Slot.it pinions for applications on Sport track chassis. It is compatible with Slot.it's usual transmission system and pairs with the same brand's crown gears to ensure correct tooth engagement.

Installation requires the use of an appropriate axle lock or set screw, depending on the receiving chassis. It is recommended to check the alignment between the pinion and crown gear before finalising the installation, to avoid premature wear and ensure quiet transmission.

Common mistakes

• Not checking the complete gear ratio: changing only the pinion without reviewing the crown gear can unbalance the setup. Always calculate the resulting ratio before installation.
• Over-tightening the set screw: ergal is softer than steel. Excessive tightening can deform the central hole and cause eccentricity in rotation.
• Not cleaning the motor shaft: any residue of grease or dirt on the shaft hinders proper fitting and can cause slipping under load.

Ideal for…

• Slot.it car tuners looking to optimise weight in moving parts.
• Club competitors fine-tuning their gear ratio according to the track layout.
• Enthusiasts assembling or tuning their slot car with top-tier components.

Frequently asked questions

What advantage does ergal have over steel in a pinion?

Ergal (high-strength aluminium alloy) weighs approximately one third of what steel weighs. In a rotating component like the pinion, this mass reduction translates to lower rotational inertia, faster motor response, and less load on the axle bearings.

Which Slot.it crown gears is this pinion compatible with?

As a standard pinion from the Slot.it range, it is compatible with equivalent pitch crown gears from the same manufacturer. Check the Slot.it catalogue or ask us to confirm the specific combination according to your setup.

What motor shaft diameter is it designed for?

This pinion is designed for 2 mm motor shafts, the usual standard in Slot.it motors.

How long does an ergal pinion last compared to a plastic one?

Ergal offers significantly greater durability than plastic under intensive use conditions, although it is generally less long-lasting than steel. For club use or regular practice, the lifespan is more than sufficient, and the weight reduction benefits far outweigh the trade-offs.

Do I need any special tools to install it?

A suitable precision screwdriver for the set screw is sufficient, or a pinion press if the installation is by fit. Slot.it and Sloting Plus offer specific tools for this type of installation.

The Slot.it SIPI7012E is a 12-tooth ergal pinion gear with a 7 mm diameter, engineered for slot car transmission systems demanding precision and low rotational inertia. Made from high-strength aluminium alloy, it reduces weight on moving parts while maintaining durability under racing conditions. Compatible with Slot.it's standard 2 mm motor shaft system and Sport track setup, it is the go-to choice for club racers and serious hobbyists looking to fine-tune their gear ratio for faster straight-line speed and sharper throttle response.