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Trans Speedo Gear Formula:
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The Trans Speedo Gear calculation determines the correct speedometer gear for a vehicle's transmission based on the axle ratio, tire revolutions per mile, and a constant value specific to the transmission type.
The calculator uses the following equation:
Where:
Explanation: The equation calculates the teeth count needed on the speedometer gear to ensure accurate speedometer readings after changing axle ratios or tire sizes.
Details: Correct speedometer gear selection ensures accurate speedometer and odometer readings, which is crucial for vehicle safety, maintenance scheduling, and legal compliance.
Tips: Enter the axle ratio as a decimal (e.g., 3.73), the actual revolutions per mile for your tires (available from tire manufacturer), and the transmission constant (typically 1000 for many transmissions).
Q1: Where do I find my tire's revs per mile?
A: Check the tire manufacturer's specifications or use a tire size calculator that accounts for your specific tire size and inflation pressure.
Q2: What if my transmission uses a different constant?
A: Consult your transmission's service manual or manufacturer for the correct constant value to use in the calculation.
Q3: Can I round the result to the nearest available gear?
A: Yes, speedometer gears typically come in whole tooth counts, so round to the nearest available option.
Q4: What if my calculated gear isn't available?
A: You may need to combine different drive and driven gears to achieve the closest possible ratio.
Q5: Does this work for all transmission types?
A: This calculation works for many mechanical speedometer systems, but some electronic systems may require different calibration methods.