Metalcloak IQ: Final Drive Ratio Calculator
Final Drive Ratio Calculator
Calculate overall gear reduction through transmission and differential
Understand how gear changes affect acceleration and top speed
inches
1st Gear Final Ratio
0:1
Total reduction in 1st gear
Top Gear Final Ratio
0:1
Total reduction in highest gear
Speed @ 2000 RPM (Top)
0mph
Highway cruising speed
| Gear | Trans Ratio | Final Drive Ratio | 20 mph RPM | 40 mph RPM | 60 mph RPM | 70 mph RPM |
|---|
Understanding Final Drive Ratios
Final Drive Ratio = Transmission Ratio × Transfer Case Ratio × Differential Ratio
Lower Final Ratio: Better acceleration, higher RPM at speed, worse fuel economy
Higher Final Ratio: Better fuel economy, lower RPM at speed, slower acceleration
Transfer Case Guide:
- 1.0:1 (2WD/4Hi): Normal highway driving - use this for realistic RPM calculations
- 2.6-2.7:1 (4Lo): Off-road crawling speeds (5-15 mph max)
- 4.0:1 (4Lo): Extreme rock crawling (1-8 mph max)
Note: For highway RPM calculations, always use 4Hi (1.0:1). The 4Lo settings are only for extreme off-road situations.
RPM Formula: RPM = (Speed × Final Drive Ratio × 377.6) / Tire Diameter