Cable Driven Speedo Corrector +20% Ratio
Ratio Box (+20%) to suit cable driven speedo's using an M22 (metric thread) speedo drive with a round drive cable.
Cable Driven Speedometer +20% Speedo Correction
Speedometer correction is required for many reasons, with larger tyres being the most common off-road vehicle enhancement requiring one of these units.
Changing your diff ratio also affects the vehicle speedometer causing incorrect speedo readings.
Calculating the Ratio
The most accurate way to determine the correction box to suit your vehicle is to use a GPS unit and compare readings to your speedo.
Drive at 60 km/h using the GPS record the speedometer reading. Repeat this step at 80 km/h and 100 km/h.
To calculate the required percentage, use the following equation
|GPS Speed||divided by||Speedometer Reading||multiplied by||100||subtract||100||equals||Ratio|
e.g. GPS reads 60 km/h and the speedometer reads 51km/h. The equation would be 60/51 x 100 - 100 = 17.65
We always recommend having a safety factor, so with the above example we would recommend a +20% unit
Marks 4WD stock ratio boxes to suit the most common ratio changes.
However, should you need a custom ratio, please contact our office with your speedo reading compared to the GPS readings at 60 km/h, 80km/h and 100km/h, so we can manufacture a custom ratio to suit your vehicle
- Ratio box plus + 20% ratio
- All vehicles using an M22 (metric thread) speedo drive with a round cable.