Performance Calculator
Gear Ratio Calculator
Calculate your final drive ratio from ring & pinion teeth, and find engine RPM at any cruising speed for your tire size and transmission gear.
Drivetrain
Use 1.00 for top-gear direct drive; enter your gear's ratio for others.
Overall tire height — use our Tire Size calculator to find it.
Final Drive Ratio
ring ÷ pinion
RPM at 70 mph
2,780
Ratio Type
Balanced
MPH per 1,000 RPM
25.2
Tire Revs/Mile
720
The gear ratio formula.
Numerically higher ratios (e.g. 4.10) give quicker acceleration and more towing grunt but higher cruising RPM and worse highway MPG. Lower ratios (e.g. 3.08) cruise calmer and more efficiently but feel lazier off the line.
Frequently asked questions.
What does a higher gear ratio do?
A numerically higher final drive (like 4.10 vs 3.55) multiplies torque to the wheels — quicker acceleration and better towing — at the cost of higher highway RPM and lower fuel economy.
Do bigger tires change my effective gear ratio?
Yes. Larger-diameter tires effectively lower your gearing (fewer wheel revolutions per mile), reducing acceleration and throwing off your speedometer. Many people re-gear after a big tire upgrade to compensate.
What gear ratio is best?
It depends on use. Daily drivers favor lower ratios (3.08–3.55) for quiet, efficient cruising; trucks and performance builds favor higher ratios (3.73–4.56) for grunt and acceleration.