Overview
Unlock serious top-speed potential on your Arrma Grom with the Hot Racing Speed Run CNC Steel Main Spur Gear — a 0.5-module 57-tooth steel spur designed for speed-run gearing setups. CNC-machined from #45 steel, this spur replaces the stock plastic ARA311196 spur with a hardened, durable steel gear capable of handling the higher torque loads of speed-run pinion combinations.
For Grom owners chasing higher MPH numbers, swapping in a smaller-tooth-count, larger-pinion-ready spur is the foundation of a proper speed-run drivetrain — and the steel construction is essential for surviving the heat and torque produced by aggressive speed-run gearing.
Key Features
- CNC #45 steel construction
- 0.5 module, 57 tooth — speed-run gearing
- Direct replacement for Arrma ARA311196 plastic spur
- Hardened steel resists wear under high-torque loads
- Designed for speed-run drivetrain configurations
Performance Benefits
- Enables higher top-speed gearing
- Steel construction far outlasts stock plastic spur
- Resists heat and stripping under speed-run loads
- Smoother, more consistent power transfer
Usage Notes
You will need a new pinion and/or motor mount plate to take advantage of speed-run gearing. Use a medium thread-locker on motor and pinion screws. Always verify gear mesh — there should be slight backlash with no binding. Inspect the spur after initial runs.
Technical Specs
- Material: CNC #45 steel
- Module: 0.5
- Tooth Count: 57T
- Function: Main spur gear (speed-run spec)
- Replaces: Arrma ARA311196 plastic spur
What's Included
- One (1) 57T steel spur gear
Fitment
- Arrma Grom (1/18 scale)
- Replaces stock ARA311196 spur gear
- Requires compatible pinion and/or motor mount plate
Summary
The Hot Racing Speed Run CNC Steel Main Spur Gear is the foundation of any serious top-speed Grom build. Hardened, durable, and ready for the demands of speed-run gearing — drop it in and chase those MPH numbers.
