Picked up one of these bags. It's huge! But perfect! I can fit a 1/8th buggy and a short course truck in there, JUST. Pockets on the side are great for sets of tires.
Works a charm as sometimes I have to take public transport to get to and from the track. I have my hauler for my tools and radio etc ... and my buggies on my back instead of stapped to the top of the hauler.