HPI Racing 40 Tooth Spool Set – Optional Locked Diff Upgrade for RS4 Sport 3

Overview

The HPI Racing 40 Tooth Spool Set is an optional drivetrain upgrade for the HPI RS4 Sport 3, replacing the standard differential with a locked spool for maximum drive efficiency. A spool delivers 100% power transfer to both wheels — ideal for drift, drag, and certain racing applications where consistent traction is more important than diff-style cornering behavior.

Precision-machined for smooth meshing and rugged construction, this upgrade is a popular choice for drift builders and racers wanting more direct power delivery.

Key Features

• Genuine HPI Racing optional upgrade
• Locked spool design (no differential action)
• 40-tooth gear count
• Precision-machined construction
• Direct fit for RS4 Sport 3

Performance Benefits

• Maximum power transfer to both drive wheels
• Predictable handling for drift applications
• Eliminates inside-wheel slip during launches
• Increased drive efficiency

Usage Notes

• Spools are best for drift, drag, and stadium racing
• Reduces cornering ability vs. standard differential
• Recommended for advanced drivers
• Use with appropriate tire compounds

Technical Specs

• Manufacturer: HPI Racing
• Part Number: 114436
• Tooth Count: 40T
• Type: Locked Spool
• Application: Optional Upgrade

Fitment

• HPI RS4 Sport 3
• HPI RS4 Sport 3 Hoonicorn
• HPI RS4 Sport 3 BMW M3 E30
• RS4 Sport 3 variants and licensed editions

What's Included

• 1x 40 Tooth Spool Set (RS4 Sport 3 Opt)

Summary

Lock in maximum drive efficiency with the HPI Racing 40T Spool Set for your RS4 Sport 3. The perfect choice for drifters and drag racers.