I'm not understanding how these work. Wouldn't changing the front and rear gear ratios just cause the truck to bind?

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

12t 22t Overdrive Gear And 24t 10t Underdrive Alloy Steel

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Fully operational. Shipping worldwide, on schedule.Duty & taxes paid at delivery

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Description

⚙️ Upgrade your RC crawler’s edge — conquer every trail with precision power!

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 TRX 4 M COMPATIBILITY - Direct replacement for front or rear axles, no modifications needed.

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.

Reviews

L**D

works great

no problem with these , very well machined

7.01.2024

J**N

Perfecto

Instalado en un TRX4m y funciona a la perfección.

9.01.2026

B**P

Poor mesh, great customer service

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.

30.12.2024

D**N

Great fit and now my TRX-4m has it great.

Beautiful made, works great in my Traxxas TRX-4m with the original crawl drive from Traxxas. Climbs great and exactly what I want it to do.

12.02.2024

C**N

Great bang for buck

Easy assemble work like a charm

10.07.2025

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TrustScore 4.5 | 7,300+ reviews

Ayesha M.

The product exactly matches the description. Very satisfied with my purchase.

5 days ago

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Perfect platform for hard-to-find items. Delivery was prompt.

1 month ago

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$79.82

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Sold byAmazon USADelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

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Trustpilot

TrustScore 4.5 | 7,300+ reviews

Neha S.

Excellent communication throughout the order process. Product is perfect.

2 weeks ago

Sneha T.

Received my product in pristine condition. Great service overall.

1 month ago

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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

12T/22T Overdrive Gear and 24T/10T Underdrive Alloy Steel Spiral Gear Set for 1/18 RC Crawler Car TRX4M Upgrade

Description

Specifications

Reviews

Common Questions