FTX Mighty Thunder Kanyon 70T Spur Gear FTX8439 large transmission cog 2-speed

Additional Information -

FTX8439 - Spur Gear 70T

What the Spur Gear Does

The spur gear is the main drive gear inside the gearbox and meshes directly with the motor pinion. Its size and tooth count play a major role in determining the overall gear ratio, affecting torque delivery, speed, efficiency, and run time.

On theFTX KanyonandFTX Mighty Thunder, the70T spur gear (FTX8439)is a key component in the 2-speed transmission.

Supply and Fitment Information

• TheFTX8439 70T spur gearissupplied as part of the complete transmission / gearbox assembly

  • FTX8440 - 2-Speed Transmission / Gearbox Assembly

• It is also available as a separate replacement spur gear

• Designed specifically for the Kanyon and Mighty Thunder drivetrain

Why Choose the 70T Spur Gear (FTX8439)

The 70-tooth spur gear provides a strong balance between torque, control, and drivetrain efficiency.

Key benefits include:

• Improved torque and smoother low-speed control

• Reduced load on the motor and drivetrain

• Increased efficiency, contributing to longer run times

• Reliable gear mesh across both gears in the 2-speed transmission

Compatible Pinion Gears (Background Information)

The following pinions are designed to mesh correctly with theFTX8439 70T spur gear:

• FTX8468 - 20T (Stock pinion)

  • Highest top speed

  • Lowest torque output

• FTX6335 - 17T (Optional)

  • Balanced torque increase

  • Moderate reduction in top speed

• FTX8432 - 15T (Optional)

  • Maximum torque and control

  • Lowest overall top speed

  • Longest run times due to improved efficiency

Reducing the number of pinion teeth increases torque and efficiency at the expense of top speed.

Compatibility

• FitsFTX Kanyon

• FitsFTX Mighty Thunder

• Used in the standardFTX8440 2-speed transmission / gearbox

• Direct replacement with no modifications required

Fitting Notes

• Always set correct gear mesh when fitting or replacing the spur gear

• Inspect the pinion gear for wear before installation

• Ensure gearbox screws are tightened evenly

• Rotate the drivetrain by hand after assembly to confirm smooth operation

Summary

• FTX8439is a 70-tooth spur gear for the Kanyon and Mighty Thunder

• It isincluded with the FTX8440 2-speed transmission / gearbox assembly

• Designed to provide improved torque, efficiency, and smooth low-speed performance

• Compatible with 20T, 17T, and 15T pinion gears

• Ideal for crawling and scale trail driving applications