Tuning Tools
Gear Ratio Calculator
Estimate vehicle speed from tire diameter, transmission gear ratio, axle ratio, and RPM. Use this as a planning tool for tire and gear changes before requesting calibration updates.
Common transmission gears: 4L60E overdrive 0.70, 4L80E overdrive 0.75, 6L80 sixth 0.67, 8L90 eighth 0.65.
Estimated Speed
0.0 MPH
Formula: MPH = RPM x tire diameter / transmission gear / axle ratio / 336. Tire and gear changes often require speedometer and shift schedule updates.
JR Jones Racing Tune Files & Cam Kits
Use these tools to confirm your engine, drivetrain, tire size, gear ratio, or RPO codes before ordering. Once you know what you have, JR Jones Racing can help match your vehicle to the correct tune file, camshaft tune, DOD/AFM delete tune, MDS delete tune, or cam kit.