Im sorry a horse leads when he gallops with his right or left hoof so it stands to reason a left lead will hug a left hand turn more smoothly than a right lead. Its an advantage and would actually in a sense make the turns at the Preakness more to his liking than the straight run at the Belmont. However I am not honestly sure if he is a left lead or a right lead I could kick myself for not checking that out when he raced but the pictures seem to indicate to me he is.
