- Product type: Spool gear (transmission component)
- Manufacturer: ARRMA
- Model number: ARA310951
- Tooth count: 39T
- Gear profile: MOD1 (Module 1)
- Bore diameter: 8mm
- Material: Steel
- Manufacturing: Precision manufactured tooth profile, precision manufactured set screw holes
- Compatible vehicles: 1/7 Felony 6S AVC 4x4 RTR, 1/7 Infraction 6S 4x4 RTR, 1/7 Infraction 6S AVC 4x4 RTR, 1/7 Limitless 120 8S AVC 4x4 RTR, 1/7 Limitless 6S 4x4 roller
- Included: 1 x 39T MOD1 spool gear (8mm bore), 1 x M4 x 4mm set screw, 1 x M4 screw pin
- Set screw specification: M4 x 4mm
- Screw pin specification: M4
- Shaft fit: 8mm diameter shaft
- Customer rating: 4 out of 5 stars
Overview
The ARRMA 39T MOD1 Spool Gear (8mm Bore) is an essential transmission component for fine-tuning the gearing performance of your ARRMA RC vehicle. Whether you're running a high-performance brushless RC monster truck, speed machine, or all-road basher, this precision-engineered spool gear allows you to optimise your vehicle's acceleration, top speed and overall handling characteristics. As a dedicated RC enthusiast in the UK, you'll understand that gearing plays a crucial role in how your RC car performs on the track or during a weekend bash session, and having the ability to swap out components like this gives you complete control over your setup.
This 39-tooth MOD1 profile spool gear is manufactured to the exacting standards you'd expect from ARRMA, one of the world's leading RC vehicle manufacturers. The gear is designed specifically for shafts with an 8mm diameter bore, ensuring a precise fit and eliminating any risk of slippage or misalignment during operation. Whether you're upgrading a 1/7 scale ready-to-run RTR model or fine-tuning a competition-spec vehicle, this component delivers the reliability and performance you need to keep your RC car performing at its best.
The 39T MOD1 Spool Gear comes complete with all the hardware you need to install it, including an M4 set screw and M4 screw pin, meaning you can get your vehicle back on the track or bash spot within minutes of purchase. Available now with UK stock and ready to dispatch, this is a must-have spare part for any ARRMA RC car owner who wants to maximise their vehicle's potential.
Key Features
- Strong and durable steel construction — This spool gear is manufactured from hardened steel, which provides exceptional strength and durability even during extreme RC driving conditions, ensuring your transmission stays reliable whether you're pushing your vehicle to the limit on the track or bashing it hard over rough terrain.
- Precision-manufactured tooth profile — The MOD1 tooth profile has been engineered with precision tolerances to deliver smooth, efficient gear meshing with your pinion gear, reducing noise, vibration and wear while maximising power transmission and keeping your drivetrain running smoothly.
- Precision-manufactured set screw holes — Both sides of the spool shaft feature precisely drilled holes designed to accommodate M4 set screws, providing an extra-secure fit that eliminates any risk of the gear slipping or rotating on the shaft during aggressive driving or high-torque situations.
- 8mm bore diameter — The spool gear is designed to fit precisely onto 8mm diameter shafts, ensuring perfect alignment and a tight, reliable connection that maintains consistent gearing throughout your driving session without any play or wobble.
- Includes all mounting hardware — The package includes everything you need to install the gear, with one M4 x 4mm set screw and one M4 screw pin supplied, so you won't need to hunt for additional fasteners.
Technical Performance
The ARRMA 39T MOD1 Spool Gear represents a premium quality transmission component engineered to exacting manufacturing standards. The 39-tooth count combined with MOD1 (Module 1) tooth profile delivers optimal gear meshing characteristics, ensuring smooth power delivery from your brushless motor through your transmission and onto the track. This spool gear is compatible with a range of ARRMA vehicles including the 1/7 Felony 6S AVC 4x4 RTR, 1/7 Infraction 6S and 6S AVC 4x4 RTR models, the 1/7 Limitless 120 8S AVC 4x4 RTR speed machine, and the 1/7 Limitless 6S 4x4 roller platform. The precision-engineered steel construction ensures the gear maintains its tooth profile over extended use, preventing the gradual wear and looseness that can affect performance in lesser components. The dual set screw mounting system, featuring M4 fasteners, eliminates any possibility of gear slip on the shaft, which is critical for maintaining consistent gearing and preventing catastrophic drivetrain failure during high-torque acceleration or competition driving. The 8mm bore is a standard specification across many ARRMA transmission designs, making this an ideal spare or upgrade component for anyone running an ARRMA RC vehicle in the UK.
What's in the Box
- 1 x 39T MOD1 Spool Gear (8mm bore)
- 1 x M4 x 4mm Set Screw
- 1 x M4 Screw Pin
Frequently Asked Questions
- What ARRMA RC models does the 39T MOD1 spool gear fit? — This spool gear is compatible with several ARRMA 1/7 scale vehicles including the Felony 6S AVC 4x4 RTR, Infraction 6S, Infraction 6S AVC 4x4 RTR, Limitless 120 8S AVC 4x4 RTR speed machine, and Limitless 6S 4x4 roller. Always verify your vehicle's specifications before purchasing to ensure compatibility with your specific model.
- Why would I need to replace or upgrade my spool gear? — Over time, spool gears can wear down due to continuous use, or you might want to swap to a different tooth count to adjust your vehicle's gearing for better acceleration or top speed. This 39-tooth option allows you to fine-tune your transmission performance to suit your driving style and track conditions.
- Is the 39T MOD1 spool gear suitable for beginners? — This is a transmission component designed for anyone comfortable with basic RC maintenance and upgrades. If you're familiar with removing and reinstalling your spool gear and have basic tools available, you'll find installation straightforward. However, if you're entirely new to RC vehicles, you may want to speak to an experienced hobbyist or visit a local RC shop to ensure you understand how to properly install and set up your gearing.
- What does the 8mm bore measurement mean? — The 8mm bore refers to the diameter of the hole through the centre of the spool gear. This must match the diameter of your vehicle's transmission shaft for the gear to fit correctly. Always verify this specification before purchasing to avoid compatibility issues.
- Do I need any additional tools or parts to install this gear? — The kit includes the set screw and screw pin needed for mounting, but you'll need basic tools such as hex keys or allen wrenches to remove your old gear and install the new one. Consult your ARRMA vehicle's instruction manual for detailed installation steps and torque specifications.
- How does the MOD1 tooth profile differ from other profiles? — MOD1 (Module 1) is a standardised gear tooth profile that provides optimal balance between strength and efficiency. The precision-manufactured MOD1 teeth on this gear ensure smooth meshing with your pinion gear, resulting in quiet, efficient power transmission with minimal wear.
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 39T MOD1 Spool Gear (8mm Bore) 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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