---
product_id: 521533048
title: "INJORA 12T/22T Overdrive & 24T/10T Underdrive Steel Helical Gear for TRX4M"
brand: "injora"
price: "$49.25"
currency: USD
in_stock: true
category: "Injora"
url: https://www.desertcart.us/products/521533048-injora-12t-22t-overdrive-and-24t-10t-underdrive-steel-helical
store_origin: US
region: United States of America
---

# Reduced vibration & noise CNC machined 20CrMo alloy steel 9% overdrive front, 16.7% underdrive rear INJORA 12T/22T Overdrive & 24T/10T Underdrive Steel Helical Gear for TRX4M

**Brand:** injora
**Price:** $49.25
**Availability:** ✅ In Stock

## Summary

> ⚡ Upgrade your crawl game with precision and power!

## Quick Answers

- **What is this?** INJORA 12T/22T Overdrive & 24T/10T Underdrive Steel Helical Gear for TRX4M by injora
- **How much does it cost?** $49.25 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/521533048-injora-12t-22t-overdrive-and-24t-10t-underdrive-steel-helical)

## Best For

- injora enthusiasts

## Why This Product

- Trusted injora brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Silent Strength:** Helical gear design drastically cuts down noise and vibration for a premium driving experience.
- • **Built to Outlast:** Alloy steel construction resists wear far better than stock plastic gears, keeping you ahead of the pack.
- • **Terrain Mastery Upgrade:** Optimized overdrive and underdrive ratios boost crawling and steering on complex terrains.
- • **Plug & Play Installation:** Easy fitment for TRX4M front or rear axles—upgrade your RC crawler in minutes.
- • **Precision Engineered Power:** CNC machined alloy steel ensures unmatched durability and smooth performance.

## Overview

This 12T/22T overdrive and 24T/10T underdrive helical gear set is CNC machined from durable 20CrMo alloy steel, designed to replace stock plastic gears on TRX4M 1/18 RC crawler cars. It reduces noise and vibration while providing a 9% overdrive to the front axle and a 16.7% underdrive to the rear axle, enhancing steering and crawling performance on challenging terrains. Easy to install, this upgrade is recommended for users aged 14 and above.

## Description

desertcart.com: INJORA 12T/22T Overdrive Gear and 24T/10T Underdrive Alloy Steel Helical Gear Set for TRX4M 1/18 RC Crawler Car Upgrade : Toys & Games

## Features

- CNC machined 20CrMo alloy steel gears, the vibration, noise, wear all less than stock gears.
- Replace the stock plastic gears, fit TRX4M front or rear axles.
- The overdrive＆underdrive alloy steel gelical gears set, helps the steering and crawling for more complex terrian.
- Using this steel gear set will allow for a 9% overdrive to the front axle and a 16.7% underdrive to the rear axle.
- Esay to install, provides a good upgrade kit for your TRX4M model car.
- AGE RECOMMENDATION: Not for children under 14 years.

## Images

![INJORA 12T/22T Overdrive & 24T/10T Underdrive Steel Helical Gear for TRX4M - Image 1](https://m.media-amazon.com/images/I/51QCuNGz2XL.jpg)

## Available Options

This product comes in different **Size** options.

## Questions & Answers

**Q: I'm not understanding how these work. Wouldn't changing the front and rear gear ratios just cause the truck to bind?**
A: Good question. If you were to drastically change the front and rear ratio (super overdrive front and rear), it would cause issues but not bind.

The slight increase spin of the front tires causes the truck to pull more front the front, instead of push more from the rear. 

This is very helpful when going over obstacles and on hill climbing

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**Shop now:** [https://www.desertcart.us/products/521533048-injora-12t-22t-overdrive-and-24t-10t-underdrive-steel-helical](https://www.desertcart.us/products/521533048-injora-12t-22t-overdrive-and-24t-10t-underdrive-steel-helical)

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*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-10-09*