Quote Originally Posted by laura* View Post
Get a Kryptonite, On-Guard, or ABUS brand "U-lock", the smaller the better (i.e. more secure).

Cable locks merely keep your bike safe from joy riding kids so that the real bike thieves can steal it.
I couldn't agree more with laura*. Cable locks are virtually useless on their own against a half competent London bike thief who will get through it in under a couple of minutes. Bike theft is a plague in my city. Hopefully they are less skilled in the places that you're visiting.

I carry a Kryptonite lock and cable if I have to lock my bike outdoors for a short period of time. If I know I have to leave it for a few hours, which is very rare, I use a gold standard Abus U lock for the frame and rear wheel and a combination cable lock for both wheels. Even then, tests show that a professional bike thief can get through that in about 5 minutes. So where you park is also important.

I don't know if this is the case with you but some insurers here will not pay out unless your lock meets a particular standard – locks are now often categorised as bronze, silver or gold standard. My insurer requires a bronze standard lock as a minimum.

Sorry for the long post but this is one of my bug bears, which on some days puts a dent in my enjoyment of cycling in London. As biciclista indicated, there is no such thing as a strong yet light lock. Perhaps I should have posted this in the Dear So and So thread.