6 calculators in this category
- Axle Gear Ratio & Final Drive CalculatorRing-and-pinion ratio identityEnter the tooth counts stamped on your ring gear and pinion and this calculator returns the axle ratio, the overall drive ratio…
- Speed from RPM Calculator (Gear & Tire)Rolling-circumference speed identityGive this calculator an engine speed, the transmission ratio in the gear you are in, the axle ratio and the tire diameter, and…
- Gear Ratio & Tire Size RPM Change CalculatorRolling circumference and final drive geometryFit taller tires and every gear in the vehicle becomes taller with them. The engine turns slower at any given road speed, the…
- Tire Diameter Calculator from Tire SizeETRTO / T&RA metric size designationType in a tire size such as 275/40R18 and this calculator returns the overall diameter in inches and millimetres, the sidewall…
- Tire Size Comparison CalculatorISO metric tire designation (P-metric / ISO 4000-1)Enter the size on your current tire and the size you are thinking about, and this calculator works out the difference in…
- Speedometer Error CalculatorUNECE R39 speedometer toleranceChange tire diameter and your speedometer starts lying, because it counts driveshaft or wheel-sensor pulses and multiplies them…
Which one do you need?
- Axle Gear Ratio & Final Drive Calculator
- Work out ring-and-pinion ratio from tooth counts, the overall final drive in every gear, cruise rpm on your tire size, and the axle ratio a regear needs.
- Speed from RPM Calculator (Gear & Tire)
- Convert engine rpm to road speed and back for any gear ratio, axle ratio and tire diameter. Includes converter slip, speed at redline and tire revs per minute.
- Gear Ratio & Tire Size RPM Change Calculator
- See your new cruise rpm, effective gear ratio, speedometer error and the axle ratio that restores stock rpm after a tire size or gear change.
- Tire Diameter Calculator from Tire Size
- Convert a metric or flotation tire size into overall diameter, sidewall height, circumference and revolutions per mile, in inches and millimeters, from the code.
- Tire Size Comparison Calculator
- Compare two tire sizes for overall diameter, sidewall, revs per mile and ground clearance, and see exactly how far your speedometer will read off.
- Speedometer Error Calculator
- Find your true road speed after a tire or axle-ratio change. Get speedometer error in mph and percent, odometer drift and the calibration correction factor.
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