Gear ratio and rate of fire
Rounds per second from motor speed, battery voltage and gear ratio.
Rounds per second
0rps
Motor rpm under load0
One cycle0 ms
How rate of fire is calculated
An AEG's motor turns a gear train; each full turn of the sector gear pulls the piston back once and fires one BB. Rounds per second follows from that:
rps = motor rpm under load ÷ gear ratio ÷ 60
Example: a stock motor (about 1,800 rpm/V) on 7.4 V, spinning at 70% under load, gives about 9,300 rpm. With 18:1 gears that's 9,300 ÷ 18.73 ÷ 60 ≈ 8.3 rps. On 11.1 V it rises to about 12.4 rps.
Reading gear ratios
| Ratio | Character | Used for |
|---|---|---|
| 18:1 | Standard, balanced | Factory gears in most AEGs |
| 16:1 | Slightly faster | A small ROF bump |
| 13:1 | High speed | High-ROF builds, paired with a high-torque motor |
| 32:1 | High torque | DMRs and snipers pulling heavy springs |
Before you chase a higher ROF
- 11.1 V packs and 13:1 gears raise the risk of pre-engagement (the next cycle starting before the piston has returned). Short-stroking and a motor swap usually go with them
- More current means thicker wire, a MOSFET and stronger switch contacts
- Many fields cap full auto (25 rps is a common limit) or ban high-ROF builds outright
Gears and motors change the rate of fire, not the energy. Energy is set by the spring, but any gearbox work can shift your chrono reading, so re-chrono after every change.