This tough steel 19T MOD0.5 Pinion Gear provides a direct replacement for your kit item.
Features
- Strong and durable steel for long-lasting performance in extreme RC conditions
- Precision manufactured tooth profile for smooth operation
- Precision manufactured set screw hole
- For 2.3mm motor shaft
Includes
1 x 19T Mod 0.5 Pinion Gear
1 x M3 x 4mm Set Screw
- Brand: ARRMA
- Part Number: Z-ARA311205
- EAN: 5052127047487
- Product Type: Pinion Gear
- Number of Teeth: 19
- Gear Pitch: MOD 0.5 (0.5 modulus metric)
- Motor Shaft Bore: 2.3mm
- Material: Hardened steel
- Manufacturing: CNC precision engineered
- Set Screw Included: M3 x 4mm
- Tooth Profile: Precision manufactured for smooth operation
- Set Screw Hole: Precision manufactured
- Compatible Vehicle Models: ARRMA 1/18 GRANITE GROM MEGA 380 (Blue/Red, Green, Red), ARRMA 1/18 MOJAVE GROM MEGA 380 (Blue, Red), ARRMA 1/16 MOJAVE GROM 4x4 RTA Race Kit, ARRMA 1/14 TYPHON GROM MEGA 380 (Blue/Silver, Blue/Silver Pre-Owned, Red/White)
- Application: Direct replacement for GROM-series brushed 4WD models
- Motor Compatibility: MEGA 380 brushed motor systems
Overview
The ARRMA Pinion Gear 19T 0.5Mod CNC 2.3mm Bore is an essential replacement part for RC enthusiasts running ARRMA small-scale models. Whether you're a seasoned RC car UK competitor or a weekend basher looking to maintain peak performance, this precision-engineered pinion gear ensures your motor drives smoothly and reliably. ARRMA has built a reputation for manufacturing high-quality RC components, and this 19-tooth pinion gear is no exception, delivering the durability and precision that serious RC drivers demand.
This tough steel pinion gear is specifically designed as a direct replacement for ARRMA GROM-series vehicles, including the popular GRANITE GROM, MOJAVE GROM, and TYPHON GROM brushed 4x4 models. The 0.5 modulus pitch and CNC-manufactured precision make this gear suitable for consistent, smooth operation in extreme RC conditions. Whether you're tackling outdoor terrain or pushing your ready-to-run RC through demanding driving sessions, this replacement gear will keep your drivetrain operating at peak efficiency.
The 19-tooth configuration paired with the 0.5 modulus specification makes this pinion gear a direct OEM replacement part for several ARRMA RTR kits. It's the kind of consumable part every serious RC enthusiast should have on hand, particularly if you regularly race or bash your electric RC car UK. With CNC precision manufacturing and a hardened steel construction, this pinion gear is engineered to withstand the punishment of modern RC driving.
Key Features
- Precision CNC Manufactured — Every tooth profile is machined to exacting tolerances, ensuring smooth meshing with your spur gear and eliminating binding or grinding that would otherwise cause performance loss and premature wear across your entire drivetrain.
- Durable Steel Construction — Made from hardened steel rather than softer brass or plastic alternatives, this pinion gear resists stripping, cracking and permanent deformation even under the extreme loads generated during high-speed racing and aggressive bashing of brushed RC vehicles.
- Precision Set Screw Hole — The M3 x 4mm threaded hole is manufactured to exact specifications, allowing secure fastening to your motor shaft without wobble, runout or the risk of the gear slipping under acceleration or heavy cornering loads.
- 19-Tooth Configuration — The 19-tooth count delivers a specific gear ratio that provides an optimal balance between acceleration and top speed for ARRMA GROM-series vehicles, maintaining the performance characteristics the vehicle was engineered for.
- 0.5 Modulus Pitch — This metric gear pitch measurement ensures perfect compatibility with ARRMA spur gears and drivetrain components, guaranteeing smooth power transmission and long component lifespan when used with genuine ARRMA parts.
- 2.3mm Motor Shaft Bore — The precisely sized bore fits standard ARRMA motor shafts without play or excessive force, making installation straightforward and ensuring the gear sits perfectly centred on your motor for optimal performance and minimal vibration.
Technical Performance
This pinion gear represents ARRMA's commitment to quality component manufacturing for small-scale RC vehicles. The 0.5 modulus specification is a metric standard measurement that defines the tooth size and pitch, ensuring this gear meshes perfectly with ARRMA spur gears in the GROM series. The CNC manufacturing process ensures that every tooth is identical, with precise flank angles and tip radii that minimise friction and noise whilst maximising power transmission efficiency. The hardened steel material is significantly more durable than plastic alternatives, resisting tooth stripping during high-load cornering and repeated acceleration cycles. The 2.3mm bore is precision-drilled and finished to ensure a snug fit on motor shafts without the binding that can occur with oversized bores or the damage risk of undersized ones. For brushed 4WD RC models running the MEGA 380 motor system found in GROM vehicles, this pinion gear provides consistent performance session after session. The included M3 x 4mm set screw allows tool-free installation using a standard hex wrench, making field replacement or gear ratio changes quick and straightforward. Whether you're running your RC car UK on tarmac, grass, gravel or dirt, this component delivers the reliability and performance you've come to expect from ARRMA.
What's in the Box
- 1 x 19T Mod 0.5 Pinion Gear (hardened steel, CNC manufactured)
- 1 x M3 x 4mm Set Screw (for securing gear to motor shaft)
Frequently Asked Questions
- Which ARRMA models is this pinion gear compatible with? — This 19T pinion gear is a direct replacement for multiple ARRMA GROM-series vehicles, including the 1/18 GRANITE GROM MEGA 380 (available in Blue/Red, Green, and Red colour options), the 1/18 MOJAVE GROM MEGA 380 (Blue and Red variants), the 1/16 MOJAVE GROM race kit, and the 1/14 TYPHON GROM MEGA 380 (Blue/Silver and Red/White options). If you own any of these brushed 4WD small-scale RC vehicles, this is the correct replacement pinion gear.
- Is this a genuine ARRMA part or a compatible aftermarket alternative? — This is a genuine ARRMA OEM (original equipment manufacturer) part, bearing the official ARRMA part number Z-ARA311205. It's the exact same component supplied with new ARRMA GROM vehicles and is the recommended replacement when your original gear requires maintenance or replacement.
- What tooth count options are available in this product line? — ARRMA offers this same modulus and bore specification in multiple tooth counts, allowing you to adjust your vehicle's final drive ratio. The 19-tooth version provides a mid-range setup; if you want faster acceleration you can step down to the 17T or 18T versions, or if you want higher top speed you can step up beyond 19 teeth. This flexibility allows experienced RC drivers to fine-tune performance for different track layouts and driving styles.
- How often will I need to replace this pinion gear? — With proper maintenance and correct mesh adjustment with your spur gear, a quality steel pinion like this should last for dozens of battery packs of driving. However, pinion gears are wear items; frequent racing, abrasive conditions, or incorrect mesh settings will accelerate wear. Having spare pinion gears on hand ensures you can keep your ready-to-run RC car UK running without downtime.
- What is the difference between 0.5 modulus and other gear pitches? — Modulus is a metric measurement of gear tooth size; 0.5 mod is a smaller tooth size compared to 1.0 mod gears. Smaller tooth gears mesh more precisely and run more quietly, which is why ARRMA specifies 0.5 mod for their GROM series. You cannot mix different modulus gears; they must all be 0.5 mod to fit properly together.
- Is installation difficult? — Installation is straightforward for anyone with basic mechanical knowledge. Simply slide the gear onto your motor shaft and tighten the included M3 x 4mm set screw using a hex wrench (typically 1.5mm or 2mm size). The only consideration is ensuring correct mesh with your spur gear, which should be set so a piece of standard paper can just slide between the teeth with slight resistance.
Why Buy from RC Model Shop?
RC Model Shop is a trusted UK RC retailer and authorised dealer for all the brands we stock, including Traxxas, ARRMA, Losi, FTX, Hobbywing, Spektrum and more. Based in Walsall, we have a physical store where customers are welcome to come in, view products and purchase in store. Whether you are a seasoned competitor, a weekend basher, or just discovering the world of RC for the first time, our team of experienced RC enthusiasts is here to help you find the perfect setup and provide ongoing support. Order the ARRMA Pinion Gear 19T 0.5Mod CNC 2.3mm Bore Z-ARA311205 today with confidence, knowing you are buying from an authorised retailer with genuine products, expert knowledge and a commitment to customer satisfaction. Shop online or visit us in Walsall — we look forward to helping you get the most out of your RC experience.
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