Listed gear-ratio data for 2025 Mercury 400 HP R Racing V10 outboards. Match your exact model and lower unit; some models may have more than one gearcase configuration.
2025 Mercury 400 HP R Racing V10
Listed ratio values: 1.60:1
| Model | Gear ratio |
|---|---|
| V10-2023-UP | 1.60:1 |
Use the ratio that matches your exact outboard model and lower unit, then enter it in the PropSlip calculator.