Lightened M2 stopper

The lightweight stopper that makes a difference in rear axle preparation

When working on the preparation of a slot car, the small details are what separate a mediocre build from a truly competitive one. The Lightweight M2 Stopper (SC-1124) from Sloting Plus is one of those details: a threaded M2 retainer designed for 2.38 mm (3/32") axles, with lightweight material to minimise unsprung mass in the rear end.

Function and performance

The stopper —also known as an axle retainer or stop— serves an essential function: to fix the lateral position of crown gears, bearings, and other components mounted on the rear axle. Without a good stopper properly tightened, any part can shift under load, causing play, rubbing, and loss of traction.

The lightweight version of this stopper reduces the mass of the part to the bare minimum, something especially valued in competition builds where every tenth of a gram on the rear axle can influence rotational inertia and, therefore, the car's response during acceleration and braking.

Compatibility

This stopper is compatible with 2.38 mm axles, the standard diameter known as 3/32", widely used in the slot car world. This type of axle is common in competition setups and custom builds on resin chassis, reinforced plastic chassis, and specific pods.

Assembly and preparation

The assembly is straightforward but requires attention:

• Insert the axle into the pod with all components already placed in their final position (bearings, crown gear, spacers).
• Screw the M2 stopper onto the axle to the desired contact point.
• Tighten with the appropriate tool —Allen key or flat screwdriver depending on the design of the fixing screw— without over-torquing, to avoid damaging the axle.
• Check for any lateral play before considering the assembly complete.

Common mistakes

• Over-tightening: this can mark or damage the axle, creating irregularities that affect turning.
• Not checking lateral play after assembly: even if the stopper appears to be well placed, it is always advisable to check that there is no play.
• Confusing axle diameter: this stopper is specific for 2.38 mm (3/32"). Do not use it on 3 mm or 2 mm axles without verifying compatibility.

Frequently asked questions

What is the difference between a standard stopper and a lightweight one?

The difference lies in the mass of the part. A lightweight stopper uses less material —through hollow geometries or lighter materials— to reduce weight on the rear axle. In competition, minimising rotational inertia improves the car's response.

For what axle diameter is the SC-1124 designed?

Exclusively for 2.38 mm axles, equivalent to the Anglo-Saxon format 3/32". Check the diameter of your axle before ordering.

Do I need any special tools to install it?

It is generally installed with a small Allen key or screwdriver, depending on the tightening screw incorporated into the stopper. Sloting Plus offers specific preparation tools that facilitate this task.

How many stoppers does a rear axle assembly usually have?

It is common to use at least one, although many builders place two (one on each side) to ensure the position of all axle components. It depends on the chassis design and the pod used.

Is it compatible with any brand of chassis or pod?

As long as the axle is 2.38 mm (3/32"), the stopper is compatible regardless of the brand of the chassis or pod. It is a universal component for that diameter.

The Sloting Plus SC-1124 lightweight M2 stopper is a precision axle retainer for 2.38 mm (3/32") rear axles, ideal for slot car competition builds where reducing rotational mass is key. Compatible with any chassis or pod using the standard 3/32" axle diameter. A must-have detail part for serious slot car preparation and tuning.