Overview
Upgrade the front differential of your Arrma 1/18 4WD Grom with the Hot Racing 30T/12T Steel Helical Diff Ring/Pinion Front Gear Set. Precision CNC-machined from high-carbon steel with a spiral helical tooth profile, this front diff gear set replaces the stock bevel ring and pinion to deliver dramatically improved strength, smoother engagement, and quieter operation.
Helical-cut gears have an inherent strength advantage over bevel gears: their angled teeth distribute load across multiple contact points simultaneously, which means more torque capacity and far less wear. For Grom owners running upgraded motors, hitting harder terrain, or simply tired of stock gear failures, this is the bulletproof front-diff fix.
Key Features
- High-carbon steel CNC spiral-cut construction
- 30T helical ring gear + 12T helical pinion gear
- Significantly stronger than stock bevel gears
- Smoother, quieter operation under load
- Precision-matched as a ring/pinion set
Performance Benefits
- More efficient power transfer through the front differential
- Higher torque capacity for upgraded motors and harsh terrain
- Reduced gear noise during operation
- Long-lasting durability — outlasts stock setups
Usage Notes
Must be installed and replaced as a matched set — never mix this helical pinion with a stock bevel ring (or vice versa). Follow the Arrma Grom kit manual for proper diff installation. Apply medium thread-locker (blue) on screws threading into metal. Hot Racing SPL10G05 high-temperature grease is recommended for the diff gears.
Technical Specs
- Material: High-carbon steel, CNC spiral-cut
- Tooth Counts: 30T ring / 12T pinion
- Gear Style: Helical spiral cut
- Position: Front differential
- Replaces: Front diff ring/pinion from Arrma ARA311177 and ARA31182
What's Included
- One (1) 30-tooth helical spiral-cut diff ring gear
- One (1) 12-tooth helical spiral-cut pinion gear
Fitment
- Arrma Grom 1/18 4WD (all variants)
- Replaces ARA311177 and ARA31182 front diff ring/pinion
Summary
The Hot Racing 30T/12T Steel Helical Diff Ring/Pinion Front Gear Set is a no-compromise front-diff upgrade for the Arrma Grom 4WD. Pair it with the matching rear set (GRM9302R) for a fully helical-geared drivetrain that's stronger, smoother, and quieter than stock from end to end.
