Forza Motorsport

Chances are you will unlock this achievement through the normal progression of the Builders Cup. If you do not, you can easily get this in a Multiplayer Race and you do not even have to actually race.

Go to Multiplayer and enter a featured race.

During practice:

Go out on track.

Once you have control, hit to bring up the menu. This ghosts your car, so no worries about interfering with others online.

Select Skip Lap

You should be pretty close to pit entrance, once you regain control, go to the pits instead of keeping on driving on the track.

Go through the pitstop menus until you get to the tire one.

Change the tire to a different compound than the one you had. Chances are you had either mediums or softs, so go for hard or even wet to be sure that it is different.

Once the pitstop is completed and you regain control, te achievement will pop.