--- product_id: 605741667 title: "12T/22T Overdrive Gear and 24T/10T Underdrive Alloy Steel Spiral Gear Set for 1/18 RC Crawler Car TRX4M Upgrade" brand: "injora" price: "57120CFA" currency: XOF in_stock: true reviews_count: 5 category: "Injora" url: https://www.desertcart.sn/products/605741667-12t-22t-overdrive-gear-and-24t-10t-underdrive-alloy-steel store_origin: SN region: Senegal --- # Easy install upgrade kit 9% front axle overdrive boost CNC machined alloy steel precision 12T/22T Overdrive Gear and 24T/10T Underdrive Alloy Steel Spiral Gear Set for 1/18 RC Crawler Car TRX4M Upgrade **Brand:** injora **Price:** 57120CFA **Availability:** ✅ In Stock ## Summary > ⚙️ Upgrade your RC crawler’s edge — conquer every trail with precision power! ## Quick Answers - **What is this?** 12T/22T Overdrive Gear and 24T/10T Underdrive Alloy Steel Spiral Gear Set for 1/18 RC Crawler Car TRX4M Upgrade by injora - **How much does it cost?** 57120CFA with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.sn](https://www.desertcart.sn/products/605741667-12t-22t-overdrive-gear-and-24t-10t-underdrive-alloy-steel) ## 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 - • **Lightweight Yet Robust:** Only 20g, delivering performance without added bulk. - • **Enhanced Terrain Mastery:** Overdrive and underdrive gears optimize crawling and steering on complex terrains. - • **Precision CNC Alloy Steel:** Crafted from durable 20CrMo steel for unmatched strength and longevity. - • **Noise & Vibration Reduction:** Spiral gear design minimizes operational noise and wear for smoother rides. - • **Seamless TRX4M Compatibility:** Direct replacement for front or rear axles, no modifications needed. ## Overview This 12T/22T Overdrive and 24T/10T Underdrive alloy steel spiral gear set is a precision CNC-machined upgrade for 1/18 scale TRX4M RC crawler cars. Made from durable 20CrMo steel, it reduces noise, vibration, and wear while boosting front axle speed by 9% and rear axle torque by 16.7%. Easy to install, it replaces standard plastic gears to enhance crawling performance on complex terrains. ## Description Product description Review: works great - no problem with these , very well machined Review: Perfecto - Instalado en un TRX4m y funciona a la perfección. ## Features - CNC machined gears made of alloy steel 20CrMo, the vibration, noise, wear are less than series gears. - Replace the standard plastic gears, mount the TRX4M front or rear axle. - The Overdrive & Underdrive alloy steel gel gear helps steer and crawl for more complex terriers. - The use of this steel wheelset allows an overdrive of 9% on the front axle and a bottom drive of 16.7% on the rear axle. - Esay to install, provides a good upgrade kit for your TRX4M model car. ## Technical Specifications | Specification | Value | |---------------|-------| | Product Dimensions | 9.91 x 2.01 x 7.11 cm; 20 g | | Item model number | 4M-10-34B | | Educational Objective(s) | Game, play | | Number of Game Players | 1 | | Assembly Required | No | | Batteries Required? | No | | Batteries Included? | No | | Material Type(s) | Steel | | Color | Black | | ASIN | B0BZLBWSRV | ## Images ![12T/22T Overdrive Gear and 24T/10T Underdrive Alloy Steel Spiral Gear Set for 1/18 RC Crawler Car TRX4M Upgrade - Image 1](https://m.media-amazon.com/images/I/51QCuNGz2XL.jpg) ## 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 ## Customer Reviews ### ⭐⭐⭐⭐⭐ works great *by L***D on 7 January 2024* no problem with these , very well machined ### ⭐⭐⭐⭐⭐ Perfecto *by J***N on 9 January 2026* Instalado en un TRX4m y funciona a la perfección. ### ⭐⭐⭐⭐⭐ Poor mesh, great customer service *by B***P on 30 December 2024* Rear underdrive gears went in fine with minimal gear noise and spins freely. Front overdrive was terrible. Ring gear was out of round and no amount of adjustment could get rid of the clicking and binding. Had to put the stock gears back in because I couldn’t get it drivable with these. EDIT: customer service sent me a new front ring and pinion and it’s on point! I have over/underdrive gears from Injora in my 1/10 crawlers and they were all great. This was the first time I’ve had an issue and it got resolved quickly. --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.sn/products/605741667-12t-22t-overdrive-gear-and-24t-10t-underdrive-alloy-steel](https://www.desertcart.sn/products/605741667-12t-22t-overdrive-gear-and-24t-10t-underdrive-alloy-steel) --- *Product available on Desertcart Senegal* *Store origin: SN* *Last updated: 2026-09-14*