OP: From your question I gather you are going to lock the bike to a rack at work. Some questions that will help us advise you better: What type of rack? Is the rack outdoors or indoors? Are there usually other bicycles parked in the rack as well or will yours be the only one? Is it visible from the street? Is it where people can see it? Is vandalism an issue or is the concern just theft? How far is the commute?