STEP 1 – Plug up your RTD Interface and your laptop to your vehicle.
NOTE: You will be using VCM Scanner BETA (not the RTD Flasher or VCM Editor) for this procedure, so open up that too.
*If you have not downloaded the VCM Scanner software, you can do so by clicking here.
STEP 2 – Connect to the vehicle by clicking on the Connect to Vehicle icon.
STEP 3 – Click the Vehicle Controls & Special Functions icon.
NOTE: If you get an empty window and do not have the option for the adjustment, click here for instructions. Complete that process, then continue on from here.
STEP 4 – Inside that box click on the Speedometer tab and select Speedometer Adjustment.
STEP 5 – The software will show the vehicle's current stored axle ratio. Enter your actual axle ratio value, even if it's the same, to be able to move forward to the next step. Input the correct value and click “OK”.
STEP 6 – Enter the new tire size. If you do not know your tire Diameter/Tire Height or Revs Per Mile (the software can show either), click here for a calculator that will do the figures for you. Tire Size Calculator
Diameter/Tire Height Example
Revs Per Mile Example
If there are any other prompts, just click “OK” on them. That’s it. Done!
