GEARBOX GUIDE
Airsoft Gear Ratio Guide
Compare common AEG gear ratios and understand how motor torque, spring load, battery, piston setup, timing, and installation quality affect the complete build.
THE BASIC PRINCIPLE
What an airsoft gear ratio means
A nominal AEG gear ratio describes the approximate reduction from the motor and pinion input to one complete sector-gear rotation. A lower numerical ratio can cycle the piston with fewer motor rotations, but it also changes the load placed on the motor and the rest of the drivetrain.
Ratio is only one variable
Trigger response, cycle speed, heat, sound, and service life are influenced by the motor, battery, spring, piston mass, compression load, wiring, gearbox alignment, lubrication, and shimming.
Avoid universal performance promises
The same ratio can behave differently in two builds. Use ratio charts as a comparison tool, then verify the complete system and test conservatively after installation.
INSIDE THE GEARBOX
How the three gears work together
An AEG gear set uses the bevel, spur, and sector gears as one matched train. The ratio describes the combined reduction through that train, not a single gear.
Bevel gear
The motor pinion drives the bevel gear. Pinion engagement, motor height, axle support, and shimming affect how this first mesh runs.
Spur gear
The spur gear transfers rotation between the bevel and sector gears. Use it as part of the matched set; visual similarity does not confirm compatible tooth geometry or spacing.
Sector gear
The sector gear pulls and releases the piston and interacts with tappet and cutoff parts in the intended design. Its active engagement teeth and stroke are separate from the printed gear ratio.
COMMON OPTIONS
Compare airsoft gear ratios
These descriptions are practical starting points, not guaranteed rate-of-fire or trigger-response figures.
Balanced AEG builds and a familiar starting point for reliability-focused setups.
Works with a broad range of matched motors and springs when correctly installed.
Confirm the exact gear set, shell, motor height, and selected product variant.
All-round builds seeking somewhat quicker cycling without moving directly to a very low ratio.
Pair with a motor that can handle the spring and overall load without excessive heat.
Check shimming, pinion mesh, piston engagement, battery, and wiring.
Response-oriented builds where faster cycling is part of a carefully matched system.
Commonly paired with a suitable high-torque motor and a battery that can support the demand.
Monitor temperature, timing, piston pickup, and overspin during controlled testing.
Speed-focused SSG builds assembled by experienced technicians.
Requires deliberate motor, spring, battery, piston, ETU, and compression choices.
Do not select by ratio alone; verify load, timing, heat, shell fit, and gear strength.
Advanced dual-sector-gear builds requiring specialist setup and tuning.
DSG timing, tappet movement, piston engagement, spring, motor, and electronics must be planned together.
Not a direct replacement for an SSG gear set. Professional installation is strongly recommended.
Extended-cylinder or platform-specific gearboxes that use a compatible tooth count and cycle geometry.
Match the sector gear and piston rack to the exact gearbox and compression layout.
SR25 naming alone does not confirm fit; verify tooth count, shell, piston, and product specification.
SEPARATE THE SPECIFICATIONS
Ratio, tooth count, and stroke describe different things
These labels answer different questions about the gearbox. Read them together, but do not use one as a substitute for another.
What the ratio describes
Labels such as 18:1, 16:1, 13:1, and 12:1 describe reduction through the gear train. A lower number means less reduction, but the label alone does not predict rate of fire, trigger response, current draw, or heat in a finished build.
What sector teeth describe
Sector teeth describe how the piston is engaged. Standard stroke, short stroke, DSG, and the 19-tooth SR25 layout are mechanical configurations, not alternate names for a ratio. For example, the JVAN SR25 AEG gear set uses a 19-tooth sector gear, while its traditional 18:1 gear-set reference uses 16 sector teeth. This tooth-count difference does not by itself prove a ratio, speed, travel, or compatibility result. Compare sector gear types.
About 100:200 and 100:300
100:200 and 100:300 are drive ratios used in the airsoft industry for AEG gear sets.
Each ratio represents a different gear configuration. They should be compared as separate gear ratios rather than converted into or substituted for one another.
SHOP GEAR SETS
Shop by Gear Ratio
Choose a gear set by ratio, tooth count, or gearbox platform.
18:1 / 16:1 / 13:1 / 12:1
Standard V2/V3 Gear Set
Four standard ratio options in one product listing.
18:1 / 16:1 / 13:1 / 12:1
Helical Gear Set
Product link coming soon.
DSG / 9:1
Dual Sector Gear Set
Dual-sector gear set in a 9:1 configuration.
SR25 / 19-tooth
SR25 Gear Set
19-tooth sector gear set for SR25-series gearboxes.
100:200
100:200 Gear Set
View 100:200 Gear Set →100:300
100:300 Gear Set
View 100:300 Gear Set →M14 VERSION 7
M14 Version 7 Gear Set
Replacement gear set for M14 Version 7 gearboxes.
SVD
SVD Gear Set
Gear set for SVD-series gearboxes.
BEFORE ORDERING
Choose a ratio as part of the complete system
Start with the intended use, then check every component that affects load, timing, and mechanical alignment.
Confirm the platform
Identify the gearbox version, shell, sector gear type, piston tooth count, bearings or bushings, trigger system, and available clearance.
Match the power system
Review motor characteristics, spring load, battery condition and output, wiring, connectors, and any ETU settings.
Plan the mechanical setup
Check shimming, motor height, pinion mesh, piston pickup, tappet timing, lubrication, compression load, and safe test procedure.
ASSEMBLY AND TESTING
Check the build at each stage
Use the product specification and the installed parts as the final reference. Stop if the gearbox binds, engagement is uncertain, or components heat abnormally.
Before assembly
Confirm the selected product, gearbox version, bushing or bearing size, piston rack, tappet components, spring, battery, and electronic-control limits.
During assembly
Install the bevel, spur, and sector gears as a matched set. Shim with the shell closed and screws tightened, set motor height from pinion-to-bevel engagement, and cycle the piston and tappet manually before powered testing.
During testing
Start with short, controlled tests in a safely assembled gearbox or replica. Stop for binding, abnormal noise, uncertain engagement, or unusual heat, then inspect the build before continuing.
COMMON QUESTIONS
Airsoft gear ratio FAQ
Short answers for selecting between common AEG gear configurations.
What is the difference between 13:1 and 18:1 airsoft gears?
13:1 gears require fewer motor rotations per sector-gear cycle than 18:1 gears, which can support quicker cycling in a properly matched build. The 13:1 setup normally demands closer attention to motor torque, battery output, spring load, heat, timing, and piston engagement.
Do 12:1 or 13:1 gears always increase rate of fire?
No fixed increase can be guaranteed. The result depends on the motor, battery, spring, piston, compression load, electronics, wiring, mechanical alignment, and installation quality.
Can I install 9:1 DSG gears in a standard SSG build?
A dual-sector gear is a specialized system rather than a simple ratio swap. It changes piston pickup and tappet timing and requires compatible piston, spring, motor, electronics, and gearbox setup.
Which gear ratio is best for a beginner build?
A balanced, well-documented setup is usually a better starting point than the most aggressive ratio. Choose a ratio supported by the exact gearbox and available components, and use an experienced technician if the installation requirements are unclear.