The SCX10 II stock axle gears are known to be a weak point in the housing. After releasing the popular Keyed 27/8T Overdrive Hardened Steel Gears, requests were sent in for underdrive gears. So YOU asked, and we listened!

Here is the new heavy-duty underdrive 33/8T helical bevel gear & diff locker set.
Designed for the AR44/AR45 Axle Housing, Boom Racing PHAT Axle Housing or the BRX70 and BRX90 PHAT Axles.

Use this gear to improve the performance of your crawler. Run them in the rear axle for a slower wheel speed in the rear tires. Underdrive gears help to steer in sharp turns like how a dig does and slower wheel speed in the back with higher torque output.

Features:
Underdrive gears create slower wheel speed for rear wheels to help steering with higher torque output
Hardened steel gears for maximum strength and durability
Keyed spool to increase structural strength and to eliminate the weakness of the M2.5 screws
Tight tolerance of the diff locker and the axle shaft
Tight tolerance of the bevel gear and input shaft to increase efficiency in the drivetrain

Fits:
Axial AR44/AR45 Stock Axle
Boom Racing BRX70 PHAT Axle
Boom Racing BRX90 PHAT Axle
Boom Racing PHAT AR44 Axle (BR955015)

Includes:
1x Keyed Heavy Duty Bevel Gear 33T
1x Heavy Duty Input Shaft 8T
1x Keyed Differential Locker (Spool)
3x M2.5 hardware
4x 1mm washer

This product will only fit one axle housing.

Replacements are available:
Diff Lock Spool