For seasons 3-5, they taped two episodes a day, one for the first half and one for the second. This way they could shoot shows with the exact same event lineup and air them months apart. This did create a problem with injuries, especially in season 3, where both Turbo, Lace, and Gold all get hurt in the middle of the first half, are fine at the beginning of the second half, and disappear again in the middle of the second half. Seasons 1 and 2 were split into halves, but they were aired in the order they were shot. Since they only had a handful of events back then, it wasn't as important to split them, since they played the exact same events every episode.