Overhyped favorites: "The biggest favorite tends to have odds out of line with their chance of winning," said Hessert. "Too many people will bet on American Pharoah (winner of the Kentucky Derby)," which means that you should probably not do the same thing. Even if American Pharoah wins, "it wasn't a good mathematically sound bet to make." (Tweet This)
The biggest long shot: "The odds for the biggest long shot should be even longer than you see," said Hessert, because lots of people take a chance on a big pay day. Tale of Verve is the biggest long shot at 30-1, which should more realistically be anywhere between 50-1 and 100-1 according to Hessert's calculations. You're paying too much at 30-1 for what you should be getting. "Again, it's not a bet you'd make money on in the long run."
Post position seven: "People just like to bet on lucky number seven, regardless of horse quality." This effect might sound silly, but it does matter. "People just like to say 'give me a hundred bucks on seven,'" said Hessert, moving the odds against you. Seven might be a lucky number, but it's not a good bet come post time. That means watch out for horse Divining Rod, who got assigned post seven. "The odds shouldn't be that strong for him."
Gray-colored horses: "People bet on gray horses because they visually stand out, but they aren't any faster," Hessert said. For the most part, the horses we see in races are brown, and the rare gray-colored ones tend to get bet on more than they should be. This year it will be easy: There are no gray horses in the Preakness. But you've been officially warned for the future. Avoid them because their odds are skewed against you.