I am looking at buying an electric bike (possible the smart ebike) -- these are not cheap. So I began to look at locks and stuff and -- these are ridiculous! 3.5-4kg even 6kg for a chain?? How do people take these things with them? I heard you should wear them like a belt but I can't quite imagine how would that work without bruising myself with the chain not to mention the padlock And then the suggestions go for two locks so I guess I would need another monstrously heavy U-lock as well. Really, how do people with multiple thousand dollars bike protect their ride when they park it in front of a cafe, cinema, school?
The lightest lock I have found which I see as "strong enough" is the Abus 401 d-lock, which weighs in at approximately 1kg. Might that be light enough for you?
Now, when I say "strong enough", what I actually mean is that this lock has a "Sold Secure Gold" rating - this is a scheme used by the UK insurance industry, which basically means that if I attach my bike to something using this lock and the bike is subsequently stolen, then my insurance company will cough up. As far as I am aware this is the lightest lock to meet this standard, and I know of no lightweight chain that I would consider appropriate.
As far as I am concerned bike locks have two purposes. First, to deter. Second, to make sure the insurance company pays out should the worst happen. They will not prevent.
Now having said that I almost never use this lock. This is because when I am out on a leisure ride, I hardly ever park the bike up. If I know I'm going to make a stop, or if I'm touring, I will carry this lock, but not otherwise.
When my bikes are at home, they're secured by (insurance approved) anchors to the garage floor by those heavy chains and d-locks that you've already discovered (in general I like the Kryptonite Fahgeddaboutit range which will deter and are insurance approved). But those locks live in the garage and don't travel.
When I am commuting, I keep a set of locks at each end. Works out expensive but as you say, they're heavy.
And yes, I mix a chain and a d-lock, both conforming to this Sold Secure Gold standard.
Note lastly that I make absolutely no claim that "Sold Secure Gold" locks are any good at what they do! In fact I've heard others say that its just a scam. But they keep the insurance company happy, that's all.
I think we had an earlier question on this and I broke it down based on what you're trying to prevent.
- Spur of the moment theft by an unprepared perp
- Targeted theft by a perp with some tools but no time
- Targeted theft by a perp well-prepared with tools and with time
For the first you only need a very lightweight lock -- I use a piece of plastic-covered aircraft cable about 1/4" in diameter and a standard padlock. This could be defeated by someone with good cable cutters, though aircraft cable (available at hardware stores) is remarkably resistant to cutting with simple wire cutters or bolt cutters.
For the second I use a commercially-available bicycle cable with a standard padlock. This can be cut through with bolt cutters, but it takes more than a few seconds. (The padlock may be more vulnerable than the cable, with the right bolt cutters.) Another option is a U lock.
There's nothing really that will deter the third (especially if equipped with a battery-powered angle grinder), other than not parking your bike in such a vulnerable location (or such a seedy neighborhood).
I do wish someone would make a cable lock with loosely braided cable. If the cable braid is loose it becomes much harder to cut through -- resistant to both bolt cutters and angle grinder. But likely it wouldn't seem as strong, and hence there's a marketing problem.
(Also note that a lock doesn't prevent someone from stealing your seat, your pedals, brake components, etc. And of course you always need to somehow lock your front wheel.)
I use the Kryptonite «New-York 3000» lock (≈ $130) which weights about 2 kg (4 lbs) for my commuter (≈ $1500). It has a frame mount which works very well. I usually lock the frame and tho wheels to the bike parking (need to unmount front wheel).
Buy a hip pouch with a u-lock holster built in. Keep your bike tools in it, and then put your u-lock in there. Alternatively you can get a u-lock braket for your frame, but I don't like them because the extra weight makes my bike slower to toss around, I prefer the weight on my body.
Not using a u-lock (or a hardened steel chain) is asking to have your bike stolen in most cities. Using quick release wheels is just asking to have them quickly stolen off a well locked frame.
It only takes someone a minute with a bolt cutter, or a few minutes with an angle grinder to steal just about any bike. Most often, it's making it less desirable to steal YOUR bike versus OTHER PEOPLES bikes. If a thief doesn't have to work too hard to steal the bike down the street, he'll probably skip yours unless he has targeted your ride.