Quote Originally Posted by shokwave2 View Post
If they wirters just kept one bike in the movie and named it Arcee, it would make everything easy. I just don't understatnd why they called the group of the bikes Arcee?
Because they were originally meant to combine as a 3-in-1 combiner, but was later dropped as the script evolved. The toys apparently have some sort of combination ability, because they started the toy designs way back before the script was changed to not have them combine.
At least that was what the Hasbro people were trying to say at BotCon about it, without spoiling too much of the movie.