I am trying to buy a chain lock as I would be leaving my cycle in quite a busy area. I am not sure what length of chain lock I will need if I wanted to secure my bike using a chain that runs through both the wheels and the frame.

The 90cm Kryptonite looks two small to run through two wheels, I am not sure if I need two 1m chain locks or if I could do with one 1.5m chain lock

I looked at the pragmasis protector 16mm chain lock with padlock. Anyone have any advice specifically on what length of chain lock i will need or if it is better to get two short chain locks both for the front and the back wheels

  • Do you not live in an area where you can reliably use a U-lock?
    – Batman
    Jun 3, 2015 at 22:13
  • To measure what length you need for a chain or cable lock, get yourself a piece of string or cord and try it, "locking" the bike to several different objects. And consider getting a U lock, then use a cable to secure the other wheel. Jun 3, 2015 at 22:58

3 Answers 3


I faced the same dilemma a while back. Getting a big chain implies carrying way too much weight around. Even a small, good bike chain is pretty heavy and can easily be 1/3 the weight of your bike.

The best way to protect your bike and be able to carry the locks around is to have a chain or a U-Lock, and with these you can easily secure your frame and a wheel, and then use a small cable like this to secure the other wheel. One wheel is less protected, but a substantial part is under a good lock and the weight is not too bad.

From these I actually prefer a small chain to a u-lock because it is easier to lock the bike to a tree for example, but if your city is bike friendly a u-lock offers very good protection and is much more manageable.

When buying locks keep in mind price usually means security. I recommend you check the independent tester of locks Sold Secure. They have a catalog with different locks they have rated.

  • +1 but I'd recommend making the cable lock completely independent of the U-lock. It's no heavier (and may be lighter if it can be shorter), means you can lock your bike to 2 separate railings (for example, or 2 loops if the bike rack is weak) and may allow you to lock your helmet up as well. Even though it's not much extra slowing down for a thief, it's still extra slowing down, and also adds flexibility. I do cable:(front wheel rim+helmet+front triangle to rack); U-lock(back wheel rim+rear triangle) to rack, filling the rest of the U-lock with a crank if necessary).
    – Chris H
    Jun 4, 2015 at 10:01

Grab some string, and thread it through where you want to lock up the bike. Then measure the string.

It won't be perfect, or even all that good, but good enough to know to the meter how much you'll need.

  • If you only lock the bike up in 1 or 2 places this might be of some use, but in practice cables and chains are less flexible than string so you'd have to guess how much to add.
    – Chris H
    Jun 4, 2015 at 10:02
  • @ChrisH of course it won't be very accurate at all.. but it should answer the question to the nearest meter. Good enough when chains are sold by the meter
    – Leliel
    Jun 4, 2015 at 21:39

You would definitely be better off buying two shorter chains rather than one long chain. With one long chain that goes through both wheels and the frame you'll be wasting a lot of chain just covering the distance between the wheels. Plus two chains gives you more locking options.

And while a 16mm Pragmasis Protector chain is an incredibly secure choice (if paired with an equally good padlock), it's completely impractical for mobile security. For example, the 1m long Protector chain with a Squire SS65CS Stronghold Lock weighs 12.13 lb (5.5 kg). That's the equivalent of nearly 15 cans of Coke!

I think a 10mm chain is about the limit of what is practically portable as an every day chain. The Kryptonite New York Noose is a good choice because the noose design means less chain goes further. You might be able to get away with the 30" (75 cm) version.

But you would still need another lock. Maybe a U-lock would be better for a secondary lock? Or have you thought about two U-locks? Whatever you choose, I wouldn't recommend anything rated less than Sold Secure Silver.

I run a website where you can compare the lengths, weights and security ratings of some of the most popular chain locks. And U-locks too. So let me know if you need anymore information!

  • But then you have to buy 2 of the most expensive item - the lock. So much better off putting the money in good long chain and one lock.
    – paparazzo
    Jun 3, 2015 at 22:03
  • If expense is your main concern then yes this is true. But if expense is your main concern, you might be better off with a U-lock. I think the weight of a chain that is long enough go through the frame and both wheels and thick enough to provide adequate security is completely prohibitive.
    – Cai
    Jun 3, 2015 at 22:14

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