Go for a battle with the Parrot Jumping Minidrone using spiked wheels !  

The design is a ring to fit inside of the parrot wheel using 4 clips to snap on. Also an M4 nut can be used to enlarge the 3D printed wheel to make a tight fit.  

The inserted wheel will still allow the dampening effect of the soft tires and the spring effect of the wheel spokes to the main body.   The 8 spikes simply scew into the ring using an M6 bolt and nut which is part of the design.  

The wheelbase STL file has the center ring, M4 bolt and 8 M6 spikes all in one file.   Have fun !