- Ratio box custom ratio
Tyre Match Box - Speedometer Correction
Speedometer correction is required for many reasons, Larger Tyres would be the most common off road vehicle enhancement requiring the use of one of these units. Differential ratios are also changed to enhance the performance of four wheel drive vehicles, this also changes the calibration of the vehicles speedometer.
Marks 4WD Adaptors now stock ratio boxes to suit two of the most common ratio changes, custom ratios are also available upon request.
If your vehicle was originally fitted with 30" tyres and is now fitted with 33" tyres your speedometer will read 10% slower that the actual road speed and if your vehicle is now fitted with 35" tyres instead of the original 30" tyres then you speedometer will be reading approximately 16.5% slower.
Should your vehicle be fitted with non standard differential ratios and tyres you can contact us to have a custom ratio box made to suit your vehicle.