Speedometer correction is required for many reasons. Larger Tyres would be the most common 4WD upgrade and differential change would be another.
Tyre size increase from 30" to 33" will give a 10% error reading on the speedo
Tyre size increase from 30" to 35" will give a 16.5% error reading on the speedo
Digital Speedo Correction MFK2800 - Tyre Match Box
Digital Speed Correction boxes are available for vehicles fitted with electronic speedometers driven by Hall Effect and Inductive Vehicle Speed Sensors (VSS)
Hall Effect VSS units can be identified as having 3 wires.
Inductive VSS units can be identified as having 2 wires.
Our electronic ratio box is unique in that it has two user selectable ratios available, switched via a 2 positioin toggle switch. One postion can be programmed for highway tyres, the second position can be programmed for off road tyres. Both ratio options are 100% user programmable and can be programmed to any speed. A GPS is the most suitable device for calibration. This speedo corrector can be calibrated to an accuracy of less than 2%.
NOTE: Most speedometers are not perfectly accurate through there entire range - this unit will not fix this problem.
NOTE: This unit is not compatiable with the following vehicle models
Toyota LandCruiser 70 Series - with ABS
Toyota LandCruiser 200 Series
Toyota Prado - automatic with ABS
Nissan Patrol - Y62
Cable Driven Speedo Correction - Ratio Box
Marks 4WD Adaptors stock mechanical speedo correction boxes to suit two of the most common ratio changes, +10% and +16.5% Custom mechanical speedo corrections boxes are available upon request.