You've tried heavy locks, chains, taking off the seat and even dragging your bike inside the building with you.
But your beloved bicycle still gets stolen, right?
Now a team of researchers at Newcastle University have come up with a novel -- and cheaper -- approach: a poster of eyes staring down at your bike.
In a two-year experiment on the university campus, the academics managed to reduce thefts from the racks by 62 per cent with the poster,combined with a short anti-theft message, according to the university website.
The posters show a pair of watchful, almost angry eyes, staring down at the bikes - almost daring anyone to do something untoward. "We are watching you," reads the warning.
“One strong possibility is that the images of eyes work by making people feel watched,” said the lead author of the paper, Professor Daniel Nettle. “We care what other people think about us, and as a result we behave better when we feel we are being observed."
In a related BBC TV interview about the study, another expert points out that humans are like other animals: they glare at any enemy to protect themselves or their belongings. "There are birds, insects, animals out there that use exactly the same principle," David Holmes told the BBC.
The results from the Newcastle study are convincing enough that campus police decided to put up those glaring posters at all the bike racks on the campus.
British Rail police are also looking at testing the system at train stations.
There was one piece of bad news, though.
While bike thefts near the eye poster went down by 62 per cent there was, as the researchers put it glumly, “a noticeable difference in places without the signs, where bike theft went up by 63%” -- suggesting that the crime had not disappeared, just been displaced.
So consider carrying around a poster with menacing-looking eyes -- but be aware the bikes down the street from you might be easy prey.