If your really stuck for this, go into any mode. Practice is best and drive around. If your in a situation Where your playing an actual game such as tournament, just boost around, preferably using an elastic band on
as well as
. Also you can play a no bot exhibition match and force a game into overtime to just drive round and score if you need the item or quit the game when you have it.
It should unlock after 75km or so. (Maybe less into your play through). Some people have claimed less distance (which can be checked in your garage and selecting the wheel you have equipped and checking the statistic for distance travelled.)
You can only get this in OFFLINE and ONLINE modes now, with the latest patch update.