GPM Racing Brass Outer Portal Drive Housing (Front or Rear)"heavy Edition"-18pcs Set for Traxxas 1/10 TRX4 (TRX4021X)

Precision heavy brass portal housings for TRX4 platforms

This heavy brass outer portal drive housing is specified for the TRAXXAS TRX4 platform and is machined from brass to increase rotating mass and axial balance. Each housing contributes approximately 50 grams at the wheel to enhance tyre contact during low-speed crawling and to improve momentum when negotiating shallow obstacles.

The housings are suitable for front or rear portal assemblies and are supplied as a matched set to preserve axle symmetry. The additional rotating mass assists wheel bite in ruts or softer terrain, allowing the vehicle to recover traction and settle back to a neutral stance with reduced oscillation.

Full mounting hardware is provided, including 16 stainless steel flat head screws sized 2.5×8. Installation is a bolt-on replacement for the stock outer portal housings; no core driveline modification is required when following standard TRX4 portal removal and refit procedures. Check torque settings and clearance during installation to maintain drivetrain alignment.

Specifications

• Item: Brass outer portal drive housing (heavy edition)
• Material: Brass
• Model Number: TRX4021X
• Compatibility: TRAXXAS TRX4
• Quantity Included: 18 pcs set
• Included Hardware: Stainless Steel Flat Head Screw 2.5×8 – 16 pcs
• Weight Effect: Adds ~50 g per wheel
• Position: Front or rear portal housings

For technical users seeking a robust, direct-fit method to add rotating mass for improved crawl behaviour, this brass outer portal housing set provides balanced weight addition and straightforward installation without altering the core driveline.

This item is compatible with

• TRAXXAS TRX4 Defender Trail Crawler

Will these housings change axle geometry?

No intentional geometry change is introduced; these housings are dimensional replacements for the stock outer portal housings. Verify fit and alignment during reassembly to ensure correct axle geometry.

What hardware is supplied and what torque is recommended?

The kit includes 16 stainless steel flat head screws 2.5×8 for mounting. Use manufacturer-recommended torque for portal housing screws and recheck after initial run-in to maintain secure fitment.

Does the added mass require drivetrain upgrades?

These housings increase rotating inertia but do not change gear ratios. For heavy-duty or prolonged climbs, monitor motor and ESC load and consider drivetrain service or reinforcements if needed.

Are the housings supplied balanced as a set?

Yes. The components are delivered as a matched set to help maintain axle balance; verify wheel and tyre condition to ensure optimal performance. Write Product Review Please sign in your account before you can write any review. Sign In Close

Made to order: GPM Racing parts are shipped to us from GPM’s factory, so please allow around 14 days for dispatch.