Eccentric universal bearing 0.3mm

Fine Adjustment of the Rear Axle with the 0.3 mm Universal Eccentric Bearing

In the preparation of a slot car, the small details make the difference between a car that runs smoothly and one that vibrates, drags, or does not transmit power effectively to the ground. The eccentric bearing is one of those components that, when used correctly, allows for fine-tuning the behaviour of the rear end with a precision that no external adjustment can match.

Technical Features

• Material: brass
• Compatible axle diameter: 2.38 mm (3/32'')
• Eccentricity: 0.3 mm
• Weight: 0.42 g per unit
• Contents: bag with 2 units

Function and Performance

The 0.3 mm eccentricity allows for variation in the position of the rear axle relative to the chassis, modifying aspects such as chassis height, preload on the rear tyres, or drivetrain alignment. By rotating the bearing within its housing, the axle is displaced in a controlled manner, offering a very fine adjustment margin without the need to machine or permanently modify the chassis.

Brass is the reference material for this type of bearing: it offers a good balance between hardness, machinability, and friction, as well as resisting wear well under continuous track use.

Compatibility and Installation

This bearing is designed for 2.38 mm (3/32'') axles, the most common size in competitive slot racing and in most chassis on the market. It is important to verify the diameter of the housing in your chassis before installation: the eccentric bearing needs to fit precisely in the housing for the eccentricity to have the desired effect and to avoid any play that would nullify the adjustment.

It is recommended to install both units from the bag on both sides of the rear axle to maintain symmetry. If only one is placed on one side, the axle will become misaligned.

Ideal for…

This bearing is particularly useful for tuners and club racers looking to optimise rear tyre contact with the track, correct small irregularities in the chassis, or adjust body height. It is also a common tool in the setup of competition cars where every tenth of a millimetre in the rear end has a direct impact on lap times.

Common Mistakes

• Confusing the available eccentricity: there are versions with different eccentricity values (0.3 mm, 0.5 mm, etc.). Make sure to choose the one that corresponds to the adjustment you need.
• Not securing the bearing after adjustment: once the optimal position is found, it is advisable to secure it so that it does not rotate due to vibration during the race.
• Installing only one of the two bearings: always work with both to ensure correct axle alignment.

Frequently Asked Questions

What is the difference between a standard bearing and an eccentric one?

A standard bearing keeps the axle centred in its housing at all times. The eccentric, on the other hand, has the hole offset from the outer centre, allowing the axle to be displaced into different positions when rotated within the housing. This offers a fine adjustment range without touching the chassis.

What is the purpose of adjusting the eccentricity on the rear axle?

Mainly to control chassis height, rear tyre preload on the track, and axle alignment with the motor. A correct adjustment can improve traction, reduce vibrations, and optimise power transmission.

Is it compatible with any slot chassis?

It is compatible with any chassis that uses a 2.38 mm (3/32'') axle and whose housing accepts bearings of the external dimensions of this model. Always check the housing measurements in your chassis before purchasing.

How many bearings do I need for a complete rear axle?

Typically, two are used, one at each end of the rear axle. This bag includes exactly 2 units, which covers a complete axle.

Can I combine bearings of different eccentricities on the same axle?

It is not recommended. Combining different eccentricity values on both sides will create misalignment of the axle, which can cause vibrations and uneven tyre wear.

The SP051200 universal eccentric bearing in brass is a precision tuning component for slot car rear axles. Designed for 2.38 mm (3/32'') axles with a 0.3 mm eccentricity, it allows fine adjustment of axle height, tyre preload and drivetrain alignment. Supplied in a pack of 2 units, it is an essential setup tool for club racers and serious slot car builders looking to optimise chassis performance and traction consistency.