I've just bought my first expensive (€820) bike and I am now concerned about the security of bike locks. I have cycled for many years and originally used only a cheap U-lock, after loosing a rear wheel I then augmented it with a cheap cable lock and would lock frame+front wheel with the U-lock and then the cable to lock the rear wheel and that has worked fine for many years, however the key point is probably that all my previous bikes were not really work stealing (<€300 new). So with the new bike I did buy and additional Kryptonite U-lock (http://www.amazon.com/Kryptonite-Evo...ef=pd_sim_sg_9). Now I have 3 locks but I'm concerned that the existing cable lock (and possibly the existing U-lock) might present no challenge to a thief. They did have locks rated up to 15 (vs 9 for my new kryptonite lock) but my problem with these is that they weigh so much. The bike was so expensive because I chose the lightest components so I don't want to negate all this by then saddling myself with an unbreakable lock which weighs half as much as the bike itself.
One option which looks promising is these kryptonite cables which can be used in conjunction with the U-lock (http://www.amazon.co.uk/Kryptonite-K...4184054&sr=1-4). Does anyone know if these are any good or might they be just as crappy as my existing cable lock ? Is there any independent measure of how secure locks are relative to one another ? Anyone have any other suggestions bearing in mind that I want best protection for a minimum weight ?