I've made a LEGO car with Caterpillar

I assembled "Tamiya Educational Construction Series No.100 : Track and Wheel Set (70100)" and attached them into the LEGO car I assembled last time.

I used 2 shafts out of the 5 shafts in the set. I connected caterpillar made of rubbers. I tried this set with my son, but this is more difficult than the slim tire set we tried last time.