Galactica Discovers Earth: Part 1 - S1-E1
Revealing mistake: When Troy and Dillon land on Earth, they take their bikes onto the freeway. They're followed by a large group of curious bikers. When two of the bikers move alongside Troy and Dillon and start talking to them, it's obvious that all four bikes are now mounted on a trailer, instead of riding on the road. Easiest way to tell is that their heads are higher up than the other bikers and the front wheel isn't turning.