Kinane has hard choice in Derby says O`Brien Aidan O`Brien admitted today that Michael Kinane will have to make 'a very hard call' as he decides which horse to ride in the Stg#1.2million Vodafone Derby at Epsom on Saturday week.O`Brien`s stable jockey must decide between Hawk Wing and High Chaparral, the two horses disputing favouritism in the ante-post betting.Hawk Wing comes into the race on the back of his fine second to stablemate Rock Of Gibraltar in the Sagitta 2000 Guineas and is the form choice but he lacks the proven stamina of High Chaparral and Kinane will have to weigh these factors out before reaching a final decision.Rock Of Gibraltar himself is unlikely to join the raiding party, despite his trainer expressing optimism today that the son of Danehill would stay a mile and a half were he to take his chance.Speaking after he had watched both Hawk Wing and High Chaparral do two steady canters on his Ballydoyle gallops, O`Brien said that the pair would do one final major workout before Epsom eitheron Friday or next Tuesday.'The Derby is the ultimate test of a horse,' he said. 'You need speed, stamina, great balance and the ability to handle all terrains.'But they are both very nice horses and I don`t have any worries about either of them - they are two very eligible horses.'I`d imagine Mick will decide two or three days before the race which horse he will ride. It`s going to be a very hard call but he makes every decision for the benefit of the team.'He`s always happy when he picks the wrong one because we learn something from it and he knows he will be on the right one next time.'Neither of them would be suited by extremes of going but as long as it was safe I would be happy for them to run.'Louisville is still in the race and could also run, as could Castle Gandolfo who has the alternative of the Prix Jean Prat. But they will not be there as pacemakers, I don`t think there`s any need for that.'Rock Of Gibraltar, who easily won Saturday`s Entenmann`s Irish 2000 Guineas, would only be considered for Epsom if Hawk Wing or High Chaparral were forced out of the reckoning.'He didn`t lose a kilo in that race,' O`Brien revealed.'Royal Ascot is the plan and we`ll take it from there although I`d say the trip doesn`t really matter -he could drop back or go up to a mile and a quarter.'You could never be sure about him staying a mile and a half but you wouldn`t be surprised if he did.'He is a really relaxed horse who is enjoying his racing and getting better all the time. He`s a Danehill and the harder they race the better they get.'As for the Derby, you can`t rule anything out but obviously there are two horses who are my Epsom horses and if they are all right then he won`t run.'The trainer, who won the race for the first time with Galileo last year, has been extensively using the replica of Epsom`s Tattenham Corner on his gallops, first utilised by his Ballydoyle predecessor Vincent O`Brien in the 1960s.'From the timethat they started training, they have cantered around that bend every day they have worked,' he said.'Hawk Wing has loads of speed and plenty of class and quickens well.'He has such pace that he would probably have no problem dropping back to six furlongs in the July Cup but having said that, is it pushing the boat out to ask a horse that could run in the July Cup to get a mile and a half.'He`ll be taking his time in the race. If he stays, he stays, and if he doesn`t then he doesn`t. That`s how he`ll be ridden.'High Chaparral won his trial as easily Galileo did last year and he was carrying 7lb more. The lads said afterwards that it had ridden like a very good race.'Bookmakers William Hill have shortened Hawk Wing`s odds to 7-4 from 2-1 for the premier Classic with stable companion High Chaparral the second favourite on 9-4.And a spokesman for Ladbrokes said: 'Hawk Wing continues to be well supported in the Derby market at 2-1 and further sustained support may see the odds shorten.'The Harrow firm has High Chaparral on 5-2.Dublin-based Paddy Power make the O`Brien stable 4-6 to win the blue riband.High Chaparral still heads Coral`s betting on 7-4 with Hawk Wing a 2-1 chance.As he bids to repeat the Derby-and-Oaks double he completed with Imagine last year, O`Brien`s team for the fillies` Classic will be led by Quarter Moon, the daughter of Sadler`s Wells who finished second to Gossamer in the Irish 1000 Guineas on Sunday.'Quarter Moon, Kournakova and Starbourne all ranvery respectable races and they could all go for the Oaks,' the trainer said.'Quarter Moon can be very fresh and she was kicking and bucking when we tried to saddle her up but she settled very well and stayed on very well.'It was very soft and her action says that there would be no doubt that she would be better on better ground.'Like almost all of O`Brien`s British raiders, all of his Classic contenders are set to travel over from Ireland only onthe day of the race.'I always prefer to travel on the day of the race but that`s probably just my preference,' he explained. 'I would rather stay in my own bed and I suppose I presume that the horses are the same.'