Good point I don t have a ready reference but I remember reading something about this distantly if someone else can find a reference There are two problems 1 A half track also has the disadvantages of both wheels and tracks the tires are not as rugged as tracks the tracks are not as quiet as tires and not suitable for high speeds or delicate uses 2 The system is inherently more mechanically complicated Any basic auto mechanic will have an idea how to fix a flat tire but a broken track Cheers