Tires Tracker Spreadsheet
 

Created a simple spreadsheet to track my tires (summer/winter) and rotation (front/rear). With this I can tell how far each pair of tires have traveled.

Pretty simple to use:

First, initial setup (summer or winter). By default it's summer. Otherwise just use the drop down.

Every time you swap or rotate tires, enter the ODO reading in the first column, then the "action" in the second column. For example, if you swapped and rotated at 1000 km, add one entry for the swapping and one entry for the rotation.