Top Gunner

Whether you know it or not, you've opened up a can of worms here. Everyone has different opinions, some relevant, some irrelevant, and people love to comment on and/or contradict other people. With that said, I'll give you my opinion...

So, you basically have cables, chains, and u-locks. I would stay away from cable locks entirely, they all can be cut within seconds by small bolt cutters. Chains and u-locks are are good, if they're the right kind. Some chains and u-locks can also be cut with bolt cutters, so I would suggest a Kryptonite, Onguard, or anothe reputable brand. Chains are more versatile in what your bike can be locked to, but they are also very heavy to commute with. U-locks are lighter, but your locking options are restricted. I don't use chains because I find the weight prohibitive, but if I did, I would use something similar to what "catonec" posted above. Instead I use u-locks, and it is rare that I cannot find something to lock it to. So, the trick with u-locks is that you want to fill up as much of the "U" as possible, otherwise that open space can be used for leverage to break the lock. This may be achieved through using a mini-u-lock and locking less of the bike (depending on size of bike as well as fixed object), or a larger u-lock and fitting more of the bike in it. Minis are light, convenient, and secure enough for most areas. I would suggest the Onguard Bulldog Mini or the Kryptonite Evolution Mini, they both weigh around 2lbs. If you want a larger lock and don't mind extra weight, the Kryptonite New York STD u-lock is about 4lbs. It is one of the highest rated u-locks out there, very secure. Kryptonite also makes the New York Fahgettaboudit Mini, which is also about 4 lbs, slightly larger than the other minis, and is often rated as the most secure u-lock on the market. Both Kryptonite and Onguard make a Mini-7 u-lock, which is basically a medium sized u-lock. Still small and light, but locking options are increased by added space.

Before you decide on a lock, you should think about how you're going to be locking your bike, and to what. Be mindful that bikes are just a series of components put together, and can be stolen as such. If possible, both wheels should be secure as well as the frame. Also, keep in mind the rear wheel is more expensive to replace than the front. There are many ways to lock a bike, if I were you I would just search online, or through some threads here and you'll figure it out. No lock is 100% secure, but some are better than others. The same can be said for locking methods. My best advice would be to bring the bike inside with you wherever you can. I put mine against a wall in the back of the classroom and people don't mind. I only leave my bike locked outside when I don't have that option.

However, regardless of what I or anyone else say, do what works for you. If a cable lock works for you, use that, if you want a heavy chain and u-lock, go for it. It's your bike, remember to enjoy yourself. Good luck!