32P 5mm Hardened Metal Pinion Motor Gear Set 13T-21T with 3.175mm Coupler for RC Cars

This HOPLEX 32P pinion gear set includes five hardened steel pinions in 13T, 15T, 17T, 19T, and 21T sizes, each with a 5mm bore and a 3.175mm bushing to fit both 5mm and 3.175mm motor shafts. Designed for RC buggies and monster trucks, the set also includes two couplers and an Allen key for secure M4 set screw installation.

Compact Specs

What does each tooth count do for your RC?

Gear ratio directly affects speed and torque. A 13T pinion gives lower top speed but stronger acceleration and climbing power. A 21T pinion does the opposite: higher top speed but less torque. The four other options let you fine-tune between those extremes. Match the pinion to your motor KV and terrain—more teeth for speed runs on flat ground, fewer for technical crawling or short tracks.

Why hardened steel and a set screw matter

Soft metal pinions wear out fast under high RPM and dirt. Hardened steel resists deformation and lasts much longer. Each gear has an M4 set screw that locks it onto the motor shaft, preventing slippage that can ruin a run. The included Allen key makes swapping gears quick.

How does the coupler work?

The 5mm bore pinions come with a 3.175mm coupler (bushing). This lets you use the same gears on motors with either a 5mm or a 3.175mm shaft. Just press the coupler into the pinion bore when using a 3.175mm shaft; remove it for 5mm shafts. No need to buy separate gear sets for different motor sizes.

What's in the package?

• 1 x 13T pinion gear
• 1 x 15T pinion gear
• 1 x 17T pinion gear
• 1 x 19T pinion gear
• 1 x 21T pinion gear
• 2 x 3.175mm couplers
• 1 x M4 hex Allen key

This set covers the most common pinion sizes for 1/10 scale RC buggies, truggies, and monster trucks using 32P spur gears. Whether you're tuning for a race or just bashing in the backyard, having five tooth counts on hand gives you the flexibility to adapt to different tracks and conditions.