geo8rge

x3 = times 3, 3 thefts of this type.
* = my own personal theft.

Locked Bicycles:
- Bicycle QR front wheel U locked to pole. QR undone and bike, less the front wheel, stolen. *
- Bicycle Cable Lock cut with bolt/cable cutter. * x4
- Cheaper U lock forced open. *
- Locked bike lifted over pole and stolen.
- Mysterious disappearance of bike and kryptonite lock. (no parts of lock or chain found) x3

Unlocked Bicycles:
- Unlocked bicycle stolen from apartment with unlocked front door.
- Bicycle left unlocked near cashier of grocery store stolen while owner shopped.
- Bicycle stolen from open unlocked garage.

Bike locks damaged:
- Kryptonite Combination U lock jammed shut by hammer attack. Bike not stolen. x2 *

Vandalism/Stolen parts:will
- Keys left in bike lock, only lock and chain stolen.
- QR for folding frame stolen *
- lock for folding frame stolen
- Bicycle frame pump forgotten on bike stolen *
- Bungee cord left on bike (who would steel that) was stolen *

As seen on TV
- Cable cut by cable cutter.
- Pole fastened to base by bolt. Bolt removed so the pole, not the bike, can be lifted and the bike stolen.

Lessons:

Always lock your bike.

Anticipate a thief lifting a locked bike over the pole the bike is chained to.

Cable locks, even thick heavy steel ones, are easily defeated (even by hand tools).

A smaller sledge hammer is a common tool, if your bike just has a U lock there are dudes that will take a shot at it, possibly jamming the lock.

It is possible to pry open the cheaper U locks.

A U+Cable lock requires thief to have 2 attacks to be successful.

With 2 locking methods it is unlikely you will fail to properly deploy both leaving your bike unlocked.

Kryptonite chains are a thing of value, and are a target; Perhaps even more valuable than the bike. Theives may be taking both the lock and chain as they are required to make a claim to Kryptonite. By taking the chain and lock, even if damaged, they reduce the chance of you filing a police report; Which you would have to do to claim the insurance payment from Kryptonite.

I have read about cases where reporting a stolen bike to police and posting on craigslist actually resulted in a recovered bike.

Identifying a stolen bike and confirming your ownership to police can be difficult. You should definitely place a sticker or note (preferably water proof) with your name on it on the seat post or other place . Registering with police is also a good idea. Etching your name on parts is more permanent, but will make selling it used harder. Record and email yourself with all serial numbers, and a picture of the bike.

Other ideas:

- Remove parts from the bike. Skewers, seat posts, QR pedals are all easy to remove from the bike and make the bike difficult to ride and sell, and less valuable.

- Allen or locking skewers (pitlock, On Guard) may help. Or may not I have seen no evidence either way. I feel enough hits with a sledge hammer will dislodge the skewer from the dropouts.

- Lubricate the lock. Oil into shackle and key hole.

As usual see SheldonBrown.com for ideas.

QR = quick release

Falkon 

If someone is going to steal my bike, there's not much I can do to stop them aside from one of those screeching locks. I have a cable masterlock as a deterrant. It's not the professional thief I'm trying to stop, it's the casual thief that just sees a bike unlocked and strolls off with it.

krazygluon

If there's a will, there's a way.

I've heard some stats that most successful thefts are crimes of opportunity. Especially since I don't live in a big biking city, I don't worry much about the professional thief. If they want my bike, they've got it regardless of anything I could do short of quadruple locking it to a telephone pole. If some opportunist comes by and sees my bike locked, he's going to keep looking unless he just walks around with bolt-cutters.

Nermal

I use that cable masterlock, too, Falkon. It's the only cable lock I've found that's long enough to secure frame and both wheels to the safety chain loop on my receiver hitch. I would not leave it on the rack overnight, though, nor at the mall for an hour.

sunofsand

Keys left in bike lock, only lock and chain stolen.


LOL, that's actually humorous

catatonic

Component theft happens as well.

I had seatpost/saddle stolen once. Why I have no idea, it was just the stock stuff from a $200 diamondback. Costed me all of $16 to replace.

I've also had misc bolts missing from my bike at times. This lead to me using oddball bolts, such as torx bits instead. The joys I had back then, living near a university.

krazygluon

Somone wanted to literally be a pain in your a$$. (Prankster vandalism)

That or they thought your saddle was pretty so they wanted it for their bike.