This tough steel 39T Mod1 Safe-D5 Pinion Gear is the perfect part to carry in your RC tool box
Features
- Strong and durable steel for long-lasting performance in extreme RC conditions
- Precision manufactured wide tooth profile for smooth operation
- 'D' shaped hole to match motor shaft profile so drive and brakes are not lost if the set-screw backs-out
- Suits 5mm motor shaft diameter
- Precision manufactured threaded set-screw hole
- E-clip supplied for motor shaft pinion retention
Includes
1 x 39T Mod1 Safe-D5 Pinion Gear
1 x Set Screw - M4 x 4mm
1 x E-Clip - 3.2mm
- Product Type: Pinion Gear
- Brand: ARRMA
- Model Number: Z-ARA311134
- EAN: 5052127043335
- Gear Pitch: Mod 1
- Number of Teeth: 39T (39-40T range)
- Bore Type: Safe-D5
- Motor Shaft Diameter: 5mm
- Set-Screw Specification: M4 x 4mm
- E-Clip Size: 3.2mm
- Material: Steel
- Construction: Precision manufactured
- Tooth Profile: Wide tooth profile
- Included Components: 1x 39T Mod1 Safe-D5 Pinion Gear, 1x M4 x 4mm Set-Screw, 1x 3.2mm E-Clip
Overview
The ARRMA Pinion Gear, 39T Mod1 Safe-D5 is an essential replacement and upgrade component for serious RC enthusiasts running ARRMA vehicles in the UK. Whether you are a weekend basher pushing your RC car to its limits, a competitive racer fine-tuning your setup, or an experienced hobbyist maintaining your fleet, this precision-engineered pinion gear delivers the reliability and performance you need. The 39-tooth configuration offers an ideal balance for many popular ARRMA models, making it a must-have spare part to carry in your RC tool box for those critical moments when a gearbox failure could ruin your session.
Manufactured to exacting standards by ARRMA, this pinion gear combines professional-grade materials with innovative safety design features. The Safe-D5 technology ensures that your motor shaft connection remains secure during intense driving conditions, whilst the Mod1 pitch specification guarantees compatibility with genuine ARRMA transmission systems. Whether you are upgrading from worn gears or simply keeping spares on hand, this 39T pinion represents exceptional value for serious RC car UK enthusiasts who demand reliability from their components.
This tough steel pinion gear is engineered to withstand the extreme demands of modern RC motorsport, from high-speed bashing on rough terrain to competitive track racing. The precision manufacturing and wide tooth profile deliver smooth, efficient power transfer with minimal noise, whilst the innovative Safe-D5 bore design protects against catastrophic drivetrain failure. If you want a pinion gear you can trust in your ARRMA vehicle, this is it.
Key Features
- Safe-D5 Bore Design — The distinctive D-shaped hole matches your motor shaft profile perfectly, ensuring that drive and brakes are not lost if the set-screw backs out during aggressive driving, keeping your RC car running safely even in extreme conditions.
- Strong Steel Construction — Manufactured from tough, durable steel, this pinion gear is built to handle the intense power demands of high-performance RC vehicles and provides long-lasting performance even under continuous stress.
- Precision Manufactured Tooth Profile — The wide tooth profile is precision-engineered for smooth operation with minimal backlash, ensuring efficient power transfer from your brushless motor to the transmission system with reduced noise and vibration.
- Mod1 Gear Pitch — The Mod1 specification ensures this gear is fully compatible with genuine ARRMA transmission systems and other components engineered to Mod1 standards, guaranteeing proper engagement and longevity.
- 39-Tooth Configuration — The 39T tooth count offers an excellent balance for many popular ARRMA models, providing suitable gearing for both speed and acceleration depending on your specific vehicle setup and driving style.
- 5mm Motor Shaft Compatibility — Designed specifically for 5mm diameter motor shafts, this pinion gear suits a wide range of ARRMA electric vehicles and modern brushless motor installations across the RC car UK market.
- Threaded Set-Screw Hole — The precision-manufactured threaded hole for the M4 x 4mm set-screw provides secure fastening and prevents stripping, ensuring your pinion remains locked in place during high-power acceleration and deceleration.
- E-Clip Retention System — Supplied with a 3.2mm E-clip for motor shaft pinion retention, this redundant safety feature provides additional security and prevents axial movement of the gear during operation.
Technical Performance
This 39T Mod1 Safe-D5 pinion gear represents the engineering excellence ARRMA has built into their drivetrain components. The Mod1 pitch specification indicates a 1mm module, which is the standard for most modern 1/10-scale RC cars and many larger models. The 39-tooth count places this gear in the mid-range configuration, suitable for balanced performance across various driving scenarios and track conditions. The Safe-D5 bore system is the result of extensive development to address real-world failure modes; the D-shaped hole prevents the gear from rotating freely on the motor shaft should the set-screw fail, a critical safety feature for UK RC drivers who rely on their vehicles for consistent performance. The precision-manufactured wide tooth profile ensures smooth mesh with the spur gear, minimising noise, vibration and wear whilst maximising power transfer efficiency. The steel construction provides superior durability compared to plastic alternatives, resisting stripping and deformation even under the extreme loads generated by modern brushless motors running on 3S or 4S LiPo batteries. The included M4 x 4mm set-screw and 3.2mm E-clip work together to create a redundant fastening system that keeps your pinion secure through every jump, corner and acceleration burst. Whether you are upgrading a tired drivetrain or building a new ARRMA vehicle, this pinion gear delivers the performance and reliability expected by serious RC enthusiasts across the United Kingdom.
What's in the Box
- 1 x 39T Mod1 Safe-D5 Pinion Gear
- 1 x Set Screw M4 x 4mm
- 1 x E-Clip 3.2mm
Frequently Asked Questions
- Is this ARRMA pinion gear compatible with my vehicle? — The 39T Mod1 Safe-D5 gear is designed for ARRMA vehicles with 5mm motor shaft diameter and Mod1 pitch transmission systems. Check your vehicle manual or specifications to confirm compatibility before purchasing. If you are unsure, contact our experienced team at RC Model Shop for advice.
- What does the Safe-D5 bore design actually do? — The Safe-D5 system features a D-shaped hole that matches your motor shaft profile. Unlike a standard round hole, this design ensures that even if your set-screw loosens or backs out during intense driving, the D-shaped connection prevents the pinion from spinning freely on the shaft, maintaining drive to your wheels and braking control. This is a genuine safety feature developed through real-world testing.
- How often should I replace my pinion gear? — Pinion gear lifespan depends on driving intensity, maintenance and setup. Weekend bashers might change pinions every 6-12 months, whilst competitive racers may change them every few months. Always carry a spare in your RC tool box, as pinion failure typically results in instant loss of drive.
- What is the difference between Mod1 and other pinion gear standards? — The Mod (module) specification defines the tooth pitch and size. Mod1 is the most common standard for 1/10-scale RC cars and many larger models. It is crucial to match the module of your pinion to your spur gear; mismatched modules will not mesh properly and will cause rapid wear and failure. Always verify your spur gear specification before purchasing a replacement pinion.
- Can I use this gear in high-temperature driving conditions? — Steel pinion gears like this 39T Mod1 Safe-D5 handle heat very well. They are perfectly suitable for summer UK driving and extended running sessions. However, ensure your motor and ESC have adequate cooling, as drivetrain performance depends on overall system temperature management.
- Is this suitable for beginners? — If you already own an ARRMA vehicle and need a replacement or spare pinion gear, this is an excellent choice. The 39T configuration is popular and versatile. However, pinion installation requires some mechanical skill; if you are new to RC maintenance, our team at RC Model Shop is happy to assist with installation guidance or service your vehicle.
- What tooth count should I choose for my setup? — The 39T configuration is a balanced choice suitable for most driving styles. Lower tooth counts (36T, 37T) favour higher top speed but require more motor power. Higher tooth counts (40T, 41T) favour acceleration and torque. The 39T sits in the middle, making it ideal for both recreational and competitive driving without extreme compromises.
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, 39T Mod1 Safe-D5 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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