I’m Dutch and have lived 12 years in Amsterdam, which doesn’t make me a know all. However I never had a bike stolen in Amsterdam, were it is said that “on average” every bike has illegally changed hands 8 times (believe it or not). So maybe my 2 pennies, tip in, on the locks topic might interest you.
Three locks mentioned in this thread so far have been:
The Dutch “horse shoe” AXA lock. This is the most commonly used lock in the Netherlands, out side of places like Amsterdam. Why? Because they are very convenient, permanently fixed to a bike. But they have a lot of down sides too. It’s very easy to walk away with a bike locked with one, just lift up the back wheel. It takes anybody 5 minutes to break one open with two strong pliers. I’ve done it several times (keys lost and for friends) and am not a strong guy. The key is permanently attached to the lock when unlocked.
The Abus Granit, is in my opinion the best lock on the market for general bike locking. My bike never got nicked using one. It’s got a complicated reliable car door type key, not easy to make a “one fit all” copy for. The U is locked at two sides, great build quality. If applied through the frame onto a solid piece of street furniture, your frame will not get nicked, in one piece at least, that is.
Kryptonite New York seems like a good lock. But I don’t like the round, security lock, type keys. They don’t provide as good a leverage when opening/closing, and get easily clogged up with street muck. I spend to much time standing in the cold trying to open locks when the key wouldn't turn. It’s even heavier then the Abus Granit.
Anyway what ever lock you have. My two rules strategy for not getting your bike nicked, would be:
1- Lock your bike onto something solid
2- Lock your bike next to a similar bike which is locked worse.
In all honesty I feel the ideal bike lock is not available on the market today. It should be a small (=lighter) size Abus Granit U lock, which will just slip around a front wheel though the bike frame. This will then allow a couple of cables to lock the rear wheel and a lamp post to be attached to the same lock. These cables are in reality quite hard to cut unless you have a bolt cutter. Even if a thieve managed to get rid of the cables he would still need an angle grinder to get through the U lock. Or he could try and walk of with a front wheel locked bike, which is a bit awkward then lifting a rearwheel. (try it some time.
)
Let me know if you’ve seen the above “Dream lock” for sale.
Cheers,
Stijn