Mosler EVO4 Medium Black chassis

The chassis that the Mosler MT900R needs to perform at its best on the track

The Mosler EVO4 Medium Black Chassis (ref. NSR1421) is the official replacement and upgrade solution from NSR for those looking to get the most out of their Mosler MT900R on the track. Part of NSR's EVO4 generation, this platform incorporates the latest improvements in geometry and stiffness that the Italian brand has developed over years of circuit competition.

Main features

• Medium size: intermediate torsion, the ideal balance between grip and top speed for most tracks and surfaces.
• Black finish: standard version of the EVO4 range, with the same geometric performance as the other colour variants in the series.
• EVO4 platform: evolution of the NSR chassis architecture with improvements in mass distribution, motor mounting points, and rear axle support.
• Made from high-strength plastic: specific material from NSR that combines lightness with calculated flexibility to absorb track irregularities.
• Direct compatibility: designed for the NSR Mosler MT900R model, with all anchor points in the correct position for a clean, modification-free replacement.

Function and performance

The chassis is the soul of any slot car. In the case of the Mosler MT900R, the EVO4 Medium platform offers a point of torsional stiffness that enhances stability during braking and the ability to rotate the front end in tight corners without losing traction in the rear. The Medium size is the most versatile in the range: if your track mixes slow corners and medium straights, this chassis responds coherently.

NSR works its chassis with very tight tolerances, ensuring that the rear axle support maintains correct alignment from the very first moment. This directly translates into less vibration, reduced tyre wear, and more predictable handling.

Compatibility and assembly

This chassis is designed for the NSR Mosler MT900R. The assembly is direct: the original body mounts on the same anchors, and the guide, braids, motor, and transmission set transfer without the need for adaptations. If you are building a competition Mosler from scratch or replacing a damaged chassis, this reference is the cleanest and safest option.

NSR is precisely one of the brands with the best selection of spare parts in the slot market, ensuring that the rest of the components —pinions, crowns, tyres, braids— are also available to complete or fine-tune the set.

Assembly and preparation: practical tips

• Before assembling, check that the rear axle and support are clean and free of burrs.
• Adjust the guide height so that the car sits correctly on the track without excessive protrusion.
• Check the alignment of the motor with the crown before finally closing the assembly.
• If you are going to compete, consider combining this chassis with NSR tyres of the appropriate profile for the type of track (universal or Sport) to optimise grip.

Ideal for…

This chassis fits perfectly with the club competitor who wants to have a spare ready for race day, with the builder who constructs cars from the ground up, and with the enthusiast who wants to bring a Mosler MT900R back to life with a deformed or broken chassis after an accident on track.

Aspects to consider

• The Medium size is the intermediate option in the EVO4 range; NSR also markets Soft and Hard versions for specific driving profiles or circuits.
• This chassis does not include motor, guide, braids, or transmission: it is sold as a bare chassis.
• Check the reference of the Mosler MT900R you have to confirm exact compatibility if your car is from a series or special edition.

Frequently asked questions

What is the difference between the EVO4 Medium chassis and the Soft or Hard?

The torsion of the chassis determines how much the body "works" in corners. The Soft yields more, favouring grip on slow or carpet tracks. The Hard is stiffer, better for fast and smooth tracks. The Medium is the midpoint, the most versatile for general use and club competition.

Is it compatible with Mosler models from other brands?

It is not designed for that. The anchor points, wheelbase, and motor position are specific to the NSR Mosler MT900R. We do not recommend attempting to adapt it to bodies from other brands without verifying dimensional compatibility.

Can I use this chassis on universal rail (Scalextric, Ninco) and Sport rail (Scaleauto, Slot.it)?

The chassis itself is compatible with both systems; what determines compatibility with the type of rail is the installed guide. NSR offers specific guides for universal rail and Sport rail, so it is sufficient to mount the appropriate guide.

Does the chassis come assembled or does it need to be put together?

It is delivered as a bare chassis, without additional components. Assembly is straightforward if you already have experience preparing NSR cars, although if you are new to preparation, we recommend relying on community resources or consulting with us.

What motor configuration is it compatible with?

The NSR EVO4 chassis for the Mosler accepts Sidewinder motorisation (motor parallel to the rear axle, transverse). Check the original configuration of your Mosler MT900R to confirm the motor position before acquiring additional components.

The NSR Mosler EVO4 Medium Black chassis (ref. NSR1421) is an official NSR replacement and upgrade part for the Mosler MT900R slot car. Part of the EVO4 platform, it delivers precise torsional balance, optimised weight distribution and direct compatibility with all NSR Mosler components. Ideal for club racing, track-day preparation or restoring a damaged chassis, this Medium flex version is the most versatile choice for mixed-layout circuits. Compatible with both universal rail (Scalextric, Ninco) and Sport rail (Scaleauto, Slot.it) setups when paired with the appropriate guide. A trusted option for slot car enthusiasts and competitive racers seeking NSR quality and reliability.