TPDs (Theft Prevention Devices)
We bought some new TPD (Theft Prevention Devices) for our bikes. We have been satisfied with the Kryptonite Evolution 4 series, and now have 3 of the latest-and-best design.
You might think that $60 (and up) is expensive for a bike lock but it is a LOT less expensive than a new bike.
We call them TPDs but they are really TDDs: Theft Deterent Devices. They should prevent the casual thief from stealing the bike. We also only lock up old bikes outside!
We never rely on any sort of cable device, they are freakily easy to cut in less than the time it took to write this sentence.
Step one is a proper lock, step two is proper bike-locking procedure.
For the record, we even lock our bikes inside the car and inside the home.
If you bike commute, We think it's highly useful to leave a lock at the bike rack at work. Just don't forget the key!
If you have any sense, don't be like us: so don't leave you bike unlocked or poorly locked and loose not one, not two, but two and a half bikes! (one was a unicycle--our favorite 24 inch Semcycle with a custom red seat)
Most thieves don't carry a complete arsenal of bike theft devices, so using multiple devices, like a Evolution lock and a serious bike chain combo is good as long as you don't have to carry it with you! But in fixed locations, like at work or as we do for the decent but old bikes (like Old Blue, our sturdy road warrior) which we keep locked outside at home, we do use both a u-lock and a chain. (repeat: we keep good bikes locked inside).