Open Question: Help finding a book?

In high school I randomly foud a book and now I can not remember the name of it. It was about a boy who loved horses, he worked at a trail riding place, i can not remember how it happened but he gets a job at a racing stables and meets a girl and a guy thats in a wheel chair. Working at stable he meets a big horse...i think he called it big red but anywho later in the book something happens with the horse and they are going to sell or put the horse down...and the boy steals the horse and runs away with it....PLZ PLZ some one tell me they read this book? Whats the name?? I really want to buy it....Thank you in advance