Highway RPM
Calculates engine RPM at a range of speeds from tire diameter, axle ratio, and transmission gear.
Cruising RPM
Estimate your Tacoma highway RPM.
Enter tire size, axle ratio, and top-gear ratio to see cruising RPM and judge whether a regear is worth it.
What it does
How this tool helps.
Regear planning
Compare RPM before and after a tire change to see how much a numerically higher axle ratio would help.
Tacoma presets
Factory axle ratios and transmission top-gear ratios by generation are built in.
Related tools and guides
Tire Size RPM Calculator FAQ.
Most gas trucks feel best cruising around 2,000 to 2,600 RPM at 70 mph. Much lower can lug and hunt gears; much higher is buzzy and thirsty.
A taller tire lowers cruising RPM for a given speed, which can feel undergeared and cause the transmission to downshift on hills. A regear restores the original RPM.
RPM equals axle ratio times MPH times transmission ratio times 336.135, divided by tire diameter in inches. The 336.135 constant comes from 63,360 inches per mile divided by 60 minutes and pi.