10-lb penalty - Dick Francis

At eighteen, easy-going Benedict Juliard has no stronger ambition than to ride as an amateur jockey. His father, immersed in politics, asks his only son to enter into a pact that neither of them will commit any act that could destroy the father's burgeoning career. Ben agrees lightheartedly, but ten years later finds himself targetted in a vicious attack mounted by his father's increasingly violent political enemies as he makes his drive towards the Prime Ministership.
In practice, a 10-lb penalty is the maximum extra weight a winning thoroughbred is normally set to carry in a race. A 10-lb penalty can be a killer.