How to stop your bike lock jamming

There’s nothing worse than a jammed bike lock. Well, there is. There’s loads of things. But when you’re struggling with a sticky key or yanking at a frozen shackle it’s difficult to think of any. Especially if it’s raining.

Jammed bike lock in the rain
Dave got angry and tried to force the key. It snapped

Your lock is meant to protect you. And now it’s trying to screw you. It’s like a good friend stabbing you in the back!

But the good news is: it doesn’t have to be this way! In the vast majority of cases, this problem can be avoided.

Here’s three top tips to stop your lock jamming. And at the end, some suggestions about what to do if your lock is already jammed!

3 tips to stop your bike lock jamming

Bike locks tend to jam in two places: in the mechanism so you can’t turn the key, or in the body so you can’t separate the two parts of the lock.

How can you tell where the problem is? It’s simple! If the key won’t go in the lock or it won’t turn properly, then obviously the problem is in the mechanism. But if the key slides in easily and turns freely but the lock still won’t open, then the problem is probably where the two parts join.

A jammed mechanism can be caused by dirt and debris, frozen water, rust or simply misaligned discs. Whereas if the lock won’t separate, then a build up of corrosion has usually fused the shackle or bar to the inside of the lock.

Luckily for you, following three simple tips will massively reduce the likelihood that you’ll suffer from either problem…

1. Buy a good quality lock

Cheap locks are a false economy. Either your bike will be stolen because they offer such poor protection. Or your lock will start to jam because it’s not properly weatherproofed and the mechanism is rubbish. Either way, sooner or later you’ll have to buy a new lock!

Get it right the first time instead. Invest as much as you can afford in a decent quality bike lock and it should last many years. With this in mind, the best locks are made by Abus, Kryptonite and OnGuard. I’ve written lot’s more about the each of these brands, but if you’re looking for the very best quality, go for Abus.

Abus U-Mini 401 YellowAbus are an especially good choice if you live somewhere with a harsh climate. Their locks are subjected to a whole series of tests at temperatures as low as -40 degrees.

And to study their resistance to corrosion, they also use a salt air chamber which ages locks one year for every day inside. No other manufacturer tests their locks as rigorously.

You should also consider buying a lock with a key cover. Key covers can stop dirt and grime entering and clogging up the mechanism. But be careful, because they can also trap water which may then freeze and then jam the lock!

2. Clean and lubricate it regularly

High quality locks don’t need much maintenance. But a good clean and lubrication every now and then never did anyone any harm! Make sure you clean and lubricate both the mechanism and the body where the two parts join.

How to treat the mechanism

WD-40 CleanerClean the mechanism with WD-40. Turn the lock so the key hole is facing upwards and then squirt the liquid into the cylinder until it streams out. This should displace any water, dirt and debris. For locks that are really gunked up, you may need to repeat this several times. Gently inserting, turning and then removing the key between squirts will help to flush the dirt out.

Once the lock is clean, you should always lubricate it. Never use WD-40 for this. WD-40 is a water displacing, cleaning agent and will ultimately remove any existing lubricant. It’s great for cleaning a lock. And it’s fantastic for loosening up a jammed lock. But it will not provide any long term lubrication.

Finish Line bike lock lubeInstead use a proper, Teflon based lubricant such as Finish Line or TriFlow. These perform well at low temperatures and repel moisture to reduce the risk of both corrosion and freezing. Put a couple of drops in the mechanism and spread it about by inserting and turning the key.

Tri-Flow lubricantSome people recommend graphite based lubricants. These are fine for dry environments. But bike locks are invariably exposed to moisture which tends to turn the graphite into a sticky mess that collects dirt and then jams the mechanism.

Stick with WD-40 for cleaning and TriFlow or Finish Line for lubrication. Use them regularly and you will have far fewer problems with stiff, unresponsive mechanisms and your locks will last much, much longer.

How to treat the body

Where to lubricate bike lock bodyYou shouldn’t need to clean the lock body too much. Just give the ends of the bar and the holes in the lock a wipe with a rag now and again. But it’s important to keep the points where the bar meets the body lubricated and free of corrosion. Especially in cold or wet climates. This will prevent the bar from starting to stick to the body.

White Lithium Grease is good for this because it’s thick, doesn’t run and will last a long time. Apply it to both the ends of the bar and the holes in the body, as and when you need to.

3. Don’t turn the key until it’s all the way in!

All locks will jam if you turn the key before it’s been fully inserted into the keyhole. Most bike lock mechanisms consist of a series of discs and all of them need to be fully rotated before the lock will open. If you try to turn the key before it’s all the way in, it won’t catch the discs at the bottom of the cylinder, so they don’t rotate and the lock won’t open.

Once this has happened, the discs are out of alignment and you won’t be able to fully insert the key and open the lock until you re-align them. To do this, turn the key back and forth as you gently push it down towards the bottom of the keyhole. If this doesn’t work you can remove the key and try to tease the discs back into place with a small flat head screwdriver.

But what can I do if my lock is already jammed?

This depends on why your lock is jammed. But the first thing to do is to give it a good squirt of WD-40. WD-40 can be a miracle cure for all sorts of jammed locks. It will displace dirt and water, remove rust and loosen the mechanism. And often this enough. However, sometimes it’s not. So…

If the mechanism is jammed

If the key won’t go all the way in, it may be because the cylinders are out of alignment. Try the method above where you turn the key back and forth and try to gently push the key further into the keyhole as the cylinders realign. If this doesn’t work, you might be able to re-align the cylinders with a flat head screwdriver. More WD-40 will help!

If the key goes all the way in but wont turn, then the mechanism may be jammed full of dirt and debris. Or maybe it’s started to corrode. Apply some more WD-40. Insert and remove the key in-between squirts of WD-40. If it doesn’t work straight away, do it again. And again. Usually, this will work eventually. Whatever you do, don’t loose your temper and try to force it. This is when the key will break off in the lock!

(By the way if your key does break off in the lock and you are lucky enough to own a Kryptonite lock, you can get a locksmith to remove the key, send the lock, the key, the key number and the locksmith bill to Kryptonite and they will refund the bill and send you a new lock!)

If you think the lock is jammed because water has frozen inside the mechanism, you’ll obviously need to melt the water before it will open! Sometimes breathing into the keyhole will do the job. Otherwise you can try warming the key with a lighter or match and then pushing it gently into the mechanism. You may need to do this several times.

If that doesn’t work and you can bring the lock indoors, then this will obviously melt the ice eventually. But spraying the mechanism with car windscreen deicer might get faster results. I have also heard of people using anti-septic hand wash! Whichever method you use, make sure it’s completely dry before you use it again outside, otherwise it will just re-freeze.

If the body is jammed

If the key goes all the way in and turns smoothly, but the lock still won’t open, then perhaps corrosion has fused the two parts of the lock together. In this case, try spraying loads of WD-40 into the joint. You’ll probably need to leave it some time for the WD-40 to do it’s magic. In fact, if you can, soak the lock in WD-40 overnight!

And once you’ve un-jammed your lock, don’t forget to give it a good clean and lubrication to reduce the chances of it jamming again.


A lot of the problems we have with jammed bike locks are avoidable. Buying a good quality lock, cleaning and lubricating it regularly and making sure you fully insert the key before you turn it will prevent the vast majority of problems. And you will be much happier.

Happiness is a well lubricated lock
Dave now: happiness is a well lubricated lock

However, modern bike locks are complex, precision instruments and sometimes they will just jam! Keeping calm and being patient is important here. Lots of WD-40 and gentle teasing in a warm environment will usually fix the problem in the end!

Of course if it doesn’t, you’re going to probably need a new bike lock. In which case, check out the 3 simple steps that will guarantee you choose the best lock for both you and your bicycle.

But what do you think? Do you have any tips to prevent locks from jamming or to un-jam stuck locks? Let me know below…


24 thoughts on “How to stop your bike lock jamming

  • February 10, 2016 at 6:35 pm

    Thanks for this great info!! Found you when trying to help my daughter unjam her Blackburn lock. She used a bike multi-tool to get the cylinders realigned.

  • April 15, 2016 at 4:16 pm

    I don’t know much about the blackburn company and have never looked it up, but I will say i don’t like their pumps. Some time just over 5 years ago, most stores around me started carrying the brand and the first one i got barely worked because the piston didn’t seal right under high pressure so it took a very long time to fill a tire to 120+ psi. The second one barely worked because the head didn’t seal aorund the stem properly unless it was held just right. In both cases, the head has a crappy and stiff lever to clamp the stem, the rubber seal in the head quckily wore out until it was a struggle to work with. The first blackburn was bought to replace a Zefal pump (aluminum body and metal metal head) that lasted 20 years of year round use without a single part replacement. I will never buy another blackburn product, especially a pump. I’ve since gone to a Topeak which has been excellent over the last few years.

  • July 1, 2016 at 11:11 am

    A good and cheap alternative to WD40 is diesel fuel. If your lock is really badly jammed and/or even rusty, try placing it into diesel fuel over night. If you slightly heat up the fuel (40°C or 105°F) it will work even better. If the lock is totally covered with diesel, it will reach every corner of the mechanism and also will wash out dirt.

    The only drawback of this method is the smell…

  • September 28, 2016 at 11:45 am

    This is really helpful, thank you. The only downside is that once I’ve used WD-40 and lube on my lock I get black grime all over my hands whenever I use my lock. Do you have any tips for cleaning the lock after lubricating it to prevent this happening?

    • September 28, 2016 at 6:34 pm

      I always use some kitchen towel and then some wet wipes!

  • October 20, 2016 at 8:35 pm

    Can you use motor oil as lubricant?

    • October 21, 2016 at 5:26 am

      Hi, You could use it if you’ve got nothing else. But it will tend to attract dirt which will end up gunking up the mechanism further down the line. Better to use the right type of lubricant in the first place in my opinion. Thanks

  • January 15, 2017 at 12:31 am

    I have now bought two magnum armoured cable locks at a total cost of about £110 and both have failed with the same fault. The key goes all the way in and turns 90 degrees easily but then stops and won’t turn another 90 degrees to open the lock. The first lock I bought I used for one summer then put the bike away in the shed for winter (using a different chain and padlock arrangement). When I came to use the magnum lock it exhibited the fault and no amount of WD 40 or jiggling the key would make it open. A local locksmith couldn’t do anything with it either. The second lock I bought in anticipation of buying an electric bike so it cost about £70. By the time I acquired the bike and started riding it out it was about 6 months after buying the lock. I went to where I’d stored it, got it out of the box it was in (inside the house and perfectly dry) and lo and behold, the same fault. I contacted masterlock but they wanted the receipt and for me to ship it and I may have to pay the investigation fee etc etc. I could have gone through all that or do what I eventually did, which was buy new locks, swearing never to go near the brand again.
    It was exactly the same fault on both locks, one unused (the keys are still on the original sales tag), which leads me to believe it’s a design fault and they should have just replaced the locks immediately.

    • January 15, 2017 at 10:49 am

      Hi Geoff

      That’s really disappointing!

      I’m not a big fan of Masterlock. I’ve generally found the quality of their locks very poor and your story unfortunately bears this out.

      Thanks for letting us know…


  • January 18, 2017 at 2:48 am

    In a pinch, I pour hot water in the lock. It just refreezes of course, but at least it gets the lock open. And hot water isn’t hard to find in a pinch 🙂

  • March 2, 2017 at 6:26 pm

    Wow – great help. I just unjammed my kryptonite lock. Boy, was I worried – I was wondering what kind of tools and how much sweat would be lost trying to forcibly break open this lock! Plus, in flat, un-hilly Bonn, where I live, my bike is like my car. Not only a useful page here, but also upbeat and humorous. Good job and thanks again!

  • March 9, 2017 at 3:10 pm

    The key goes all the way in and turns smoothly in my Bell u-lock. The lock opens and closes but the key don’t slide out of the cylinder. I disassembled the u-lock, removed the cylinder and discovered that when the key is pulled the pins don´t slide to release the key, even with the cylinder disassembled. I think the pins are worned out and they don´t slide out of the key’s grooves and probably only a new lock solves the problem.

  • April 27, 2017 at 9:21 pm

    Can you use Vaseline to lubricate the lock?

    • April 30, 2017 at 2:35 pm

      I wouldn’t recommend it. It will probably work OK at the start. But it’s likely to attract all sorts or dirt and dust which will ultimately clog up the lock. Better to get some proper lock lubricant.

  • May 17, 2017 at 4:53 pm

    I got a new uGrip BORDO 5700 as a gift some months back. Went to use it. Keys enter fully but won’t turn lock. Brand new.

    • May 17, 2017 at 7:36 pm

      Pfff that’s pretty bad. You should send it back.

  • June 5, 2017 at 7:25 pm

    Hi my bike lock is magnum plus one of the high security lock the key turns but not unlocks its locks out where i work and can not do anything. Please success me what can I do.
    Thank you.

    • June 7, 2017 at 10:31 pm

      Sound like the body is jammed. Have you tried spraying WD-40 in the joints where the shackle meets the body?

  • June 22, 2017 at 10:09 pm

    First comment I have shared but hoping it may be of use to others! I had tried many of the solutions above (WD-40, special rust remover, etc) over a period of weeks and still the key would not turn. Then one day I had the idea to use some of that quick working sink and drain unblocker – poured it down the key whole – waited a few mins – and it opened first time!. I guess WD-40 is not that good at desolving biological dirt trapped inside the lock. Take all precautions etc. as this stuff is strong. I then gave a good dose of WD-40 and it’s been perfect ever since!

    • June 23, 2017 at 11:00 am

      Brilliant! That’s fantastically helpful Rob. Thanks!

  • September 15, 2017 at 11:39 pm

    I used to have a lock that would get jammed and I could fix it with a paper clip, so I still carry a paper clip when using bike locks. I guess I should keep them properly lubricated too, though.

  • September 21, 2017 at 5:52 am

    My bike was stolen in June so I bought an ABUS U-Lock GRANIT X Plus™ 540 for my current bike, as recommended by the bike dealership. After a few months of summer weather and with with absolutely no traumatic hits, the lock just stopped working. The key turns, allowing the bars in but will not turn back to lock. Neither DW40 or any kind of grease does anything.

    This was a pretty expensive lock for a few months use so unlike the owner of this site I can only recommend dodging the use of anything ABUS in future. Naturally, their website only offers upselling as answers to any question one might have.


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