Relying on a cheap lock and good-hearted strangers to protect your bike? Don't...

How long do you have to be hacking away at bike lock before someone asks you what’s going on? As much as three minutes if this video from a couple of students at Nottingham Trent Uni is anything to go by.

As part of a design project, the students thought they’d find out how long you can spend attacking a bike lock before someone notices and has a word with you.

Mocking up an attack on a lock with a blunt hacksaw, the students made no attempt to conceal what they were doing - no boltcroppers hidden under a long coat here, one of them simply went at it with the saw till someone asked what was going on.

The average time they went unmolested was 2 minutes 22 seconds, but in one sequence the ‘thief’ spent three and a half minutes going at the lock while being filmed from a discreet distance. He actually starts to look pretty bored.

Two minutes doesn’t sound very long, but Stephen Briggs of bike security company Pragmasis says it’s plenty of time for a skilled thief to take off with your bike.

Stephen told us: “Most bikes are 'locked' with cable locks, and you can cut through most of the unarmoured ones with a junior hacksaw, like he used (albeit not blunt) in less than 30 seconds.

“If you use the sort of cable cutters you can get from Machine Mart etc for around £15, you can cut them all in about a second. Even the armoured ones are mostly easy to defeat with cable cutters or bolt croppers or hammers.”

Between that information and the video, the advice is simple: steep clear of cables of any sort as your main lock.

A chain or D-lock is a far better bet, says Stephen, though the quality there is variable, and the way you use them makes a big difference. “Our chains have to survive a 5-minute sawing test for the Sold Secure Bicycle Gold approval, and that's when they're held in a vice,” he says.

“However, thin chains (10mm or less) are all relatively easy to cut with bolt croppers. Bicycle thieves tend to use small croppers (e.g. 18in or 24in) that are quite limited in the amount of leverage they can exert, but having a chain anywhere near the ground makes the croppers much easier to use.”

That’s because if a chain is close to the floor, the thief can rest the cropper on the floor and use all his weight to cut the chain.

Badly used, a thin (under 8mm) or low quality chain is again seconds work for a thief with croppers.

“A good chain, 10mm+, up high, is a much tougher target for thieves,” says Stephen. “We don't guarantee it, but we'd expect our 11mm chain to stop 24" croppers, even if it is lying on the floor.”

What about D-locks, long considered the gold standard of bike security?

“Cheap ones can be broken easily with twisting/levering attacks if you don't fill the space inside the 'D' thoroughly and if there is something to lever against (e.g. railings, Sheffield stand, even the bike),” says Stephen. “Medium D-locks can be cut with hacksaws & bolt croppers similar to chains.”

Buy a good one, then, and fill it with the bike and whatever you’re locking it to. That’s a point Stephen was very keen to emphasise.

“It is vital that it is used to lock the bike to something solid, and not another bike!” he says.

“We've had cases of frames being cut to release another bike. This is another type of attack that can be fast and quiet, taking e.g. 30 seconds to hacksaw through the frame of a bike to steal it (for its components) or to steal an attached bike (with the chain etc still attached).

“Putting the chain/D-lock through the main triangle of the frame and the rear triangle and the rear wheel, and locking the bike to a Sheffield stand etc that is genuinely solid, deters these component/secondary attacks.”

“All in all,” he add, “most bikes that get nicked are stolen easily and in seconds, and passers-by won't take any notice. People need to take responsibility for their own security and match the deterrent to the nickability of the items concerned.”

This isn’t the first mocked-up bike theft video we’ve brought you. Last year police in Cambridge — the bike theft capital of the UKdemonstrated just how easy it is to steal a bike. Security company Bike Dock Solutions also has a video demonstrating how little notice passers-by take of thieves.

Last July, London police produced two useful videos about bike theft.

Over the years we’ve compiled what we think is the definitive set of anti bike theft tips, with input from the road.cc community, and much of it aligns with Stephen Briggs’ advice, so here it is again to cut out and keep.

The road.cc community Bike Locking Bible

  • Lock your bike to a secure, immovable object. Trees and certain pieces of street furniture don’t make particularly good locking locations; trees limbs can be sawed through, and your bike can often be lifted over bollards and signposts.
  • Your wheels are the most vulnerable part of your bike. Make sure that your lock goes through both wheels and the frame, or use two locks: one for each wheel. Alternatively you can invest in a locking wheel skewer for your front wheel.
  • It doesn’t take long to steal a bike. Make sure that you lock your bike up properly whether you are leaving it for 30 seconds or half an hour.
  • Bike lights and other items and accessories that are not secured to your bike are easy pickings for thieves. Take them with you whenever you leave your bike.
  • No matter how safe you feel in your home, your bike is still at risk, especially if it’s in your garage or your shed. Lock it up at home like you would if you were on the street.
  • Not all bike locks are cheap, but you really do get what you pay for. If you treasure your bike, buying the best locks that you can afford would be a wise investment.
  • If you come back to your bike and it's got a mysterious puncture or damage, walk it home. It's probably been marked in the hope that you'll leave it there overnight.
  • Consider using a registration service, such as Bike Register, to physically mark your bike with an identifying feature and link it to your identity on the police database. Certain councils and police constabularies offer free solutions, and there are alternatives to Bike Register.
  • If it does go missing you must report it. The police will only take bike crime more seriously if they have reason to do so.
  • If you're down to one lock, or are particularly worried about the security of your wheel, taking your front wheel with you eliminates half of the risk of theft immediately.
  • Use secure bike parking wherever possible. Even for a price, your bike will be far better protected from theft inside a designated secure location rather than on the street, no matter how well you think you’ve locked it up.
  • Make sure that you lock your bike up in as public of a place as possible. If you leave it in a secluded location, it will give any would-be thief time to work on your lock undisturbed.
  • Make the lock mechanism itself hard to access. For example if you're locking your bike to railings, point the lock mechanism away from the street so it's harder for a thief to attack.
  • Don't leave space in your shackle - any extra space gives evil bike stealing tools the room they need to do their dirty work. Don't give them that opportunity.
  • If you’ve taken out insurance on your bike don’t buy any old lock. Make sure that the locks that you have purchased are featured on Sold Secure’s approved products list as many insurance companies insist on their use.
  • But most importantly, wherever you’re going, please do not forget your lock!

Our official grumpy Northerner, John has been riding bikes for over 30 years since discovering as an uncoordinated teen that a sport could be fun if it didn't require you to catch a ball or get in the way of a hulking prop forward.

Road touring was followed by mountain biking and a career racing in the mud that was as brief as it was unsuccessful.

Somewhere along the line came the discovery that he could string a few words together, followed by the even more remarkable discovery that people were mug enough to pay for this rather than expecting him to do an honest day's work. He's pretty certain he's worked for even more bike publications than Mat Brett.

The inevitable 30-something MAMIL transition saw him shift to skinny tyres and these days he lives in Cambridge where the lack of hills is more than made up for by the headwinds.