Like you got all these vehicles and racers and many of them aren't capable of being used for racing. If this were to happen in real life, many of them would either lose or be incapable of winning.
Some very good examples include tractor who would instantly be in last for obvious reasons and dump truck who wouldn't even be able to stay in first (let alone 3rd or 4th) due to his design, theoretical real life speed (which I'll assume is probably 70-85 mph), and weight. It was literally made to be unfair if I gotta be honest.
Of course I shouldn't complain too much since it's just a kids show and logic doesn't really apply.