Front and Rear Carbon Pulleys 8mm Inline

The carbon fibre pulleys 3DSRP SRP018110 are designed for those who fine-tune every tenth in their all-wheel-drive rally slot setups.

This pack includes a front and a rear pulley with a 8mm diameter, specifically designed for inline motor configurations — where the motor is positioned longitudinally, in line with the car's axle — where a well-calibrated belt drive makes the difference between smooth propulsion and one with energy losses. The choice of material is not coincidental: ASA filament with carbon fibre, processed through FDM 3D printing, combines structural lightness and fatigue resistance from continuous rotation cycles.

Function and performance

In a 4WD system for 1/32 scale rally and raid models, the pulleys are the critical link between the motor and the axles. An improperly proportioned profile or excessively heavy material introduces rotational inertia that delays acceleration response and affects the regenerative braking of the belt. The construction in ASA with carbon fibre from 3DSRP reduces that weight to the minimum necessary, maintaining dimensional rigidity so that the belt does not slip or jump under high torque.

The 8mm diameter offers a balanced gear ratio for most common inline configurations in club rally slot competition. The pulleys feature engraved markings — via dots — indicating the inner diameter, facilitating quick identification in the workshop without the need to measure each time.

Compatibility

• Front axle: compatible with the standard front axle of these 4WD sets.
• Wheels: designed to fit with Sloting Plus wheels.
• Belt: accommodates belts up to 1.5mm section.
• Scale: intended for 1/32 slot cars in all-wheel-drive configuration.

Assembly and preparation

As these are 3D printed parts using FDM technology, it is advisable to check the fit on the axle before first use. If the inner diameter requires a slight tolerance adjustment, a light touch-up with a fine-grit needle file is sufficient to achieve a perfect fit without play. It is also recommended to check the belt tension after assembly: an overly tight belt increases friction and wear; too loose causes skipping under rapid acceleration.

For optimal initial running, it is advised to run the assembly in free rotation for a few minutes at low power before demanding competition levels.

Common mistakes

• Using belts with a section greater than 1.5mm: this can stress the pulley profile and cause premature deformation.
• Not checking the alignment between the front and rear pulleys before closing the chassis: a slight misalignment generates asymmetric wear on the belt and noticeable vibrations on track.
• Applying excessive lubricant on the belt: this reduces traction and may degrade the ASA filament over time.

Frequently asked questions

What is the difference between an inline and a sidewinder setup regarding the use of pulleys?

In an inline setup, the motor is oriented longitudinally (in line with the car), and the transmission to the rear axle — and in 4WD systems also to the front — is typically done via a belt. In a sidewinder, the motor is transverse to the rear axle and usually transmits directly via pinion-crown gear, without the need for belt pulleys. These SRP018110 pulleys are designed for inline configurations.

Does the pack include only pulleys or also the belt?

The pack contains 2 pulleys (one front and one rear). The belt is not included and must be purchased separately, ensuring that its section does not exceed the 1.5mm indicated by the manufacturer.

Are they valid for any 1/32 rally slot car with 4WD?

They are designed for inline 4WD setups in 1/32 scale that use Sloting Plus wheels. Compatibility with other wheels or chassis will depend on the specific dimensions of each set, so it is advisable to verify measurements before assembly.

What advantage does ASA filament with carbon fibre offer over conventional plastic?

ASA offers greater resistance to temperature and repeated load cycles than the usual ABS or PLA. The addition of carbon fibre increases the rigidity of the part and reduces its weight, resulting in less rotational inertia and a more responsive acceleration.

How do I identify the inner diameter of each pulley?

The design itself incorporates raised dots that indicate the inner diameter, allowing them to be distinguished at a glance without the need for calipers.

The 3DSRP SRP018110 carbon fibre pulley set is engineered for 1/32 scale 4WD rally slot cars running inline motor configurations. Made from ASA filament reinforced with carbon fibre and produced via FDM 3D printing, these front and rear 8mm pulleys deliver low rotational inertia and high structural rigidity for belt-drive transmission systems. Compatible with Sloting Plus wheels and belts up to 1.5mm section. A precise, lightweight upgrade for competitive club racing and rally slot builds.