Bike alarm

This article was published in 2002, in Newsletter 43.

When Douglas De Lacey mentioned (on the camcycle mailing list) that there was a reasonably priced bike alarm for sale, I got the last one in stock to try it out.

I fitted it to my Brompton folding bike. The good news is that I still have a Brompton!

Image as described adjacent
Cycle alarm lock. £9.95 from Maplins, Regent Street or mail order.

The lock is about 10 x 5 x 5 cm. It comes with a holster that attaches to one of the bike tubes. Therein lay the first problem: because of the Brompton’s large tubing and folding mechanism, the number of places to attach it is limited. I ended up strapping it on with cable ties instead of the supplied fittings. You could carry it separately, of course, but then it’s one more thing to carry.

The other problem with the holster is that it is too easy to forget that the alarm’s cable must go through the frame as well as the bike rack. Otherwise, the lock can be removed from the holster and the bike taken away leaving the lock attached to the stand.

Of course the alarm should sound if you do this. The alarm is very loud (110 dB). It goes off for 20 seconds if you disturb it, or 30 seconds if you cut the cable or otherwise break the circuit. The former is easier to test but, for obvious reasons, I haven’t checked the latter. The alarm gives you three loud warning beeps if you move it before going off fully. It seems quite good at not going off if the bike is lightly knocked, but I doubt it would stay quiet if a bike were parked in the same stand given how close they are together. For that reason I’d have to be very careful about where I leave it.

But the biggest problem is that it is extremely sensitive to being unlocked. If it is not held perfectly still while unlocking, it goes off (with the warning beeps, and if you can’t get the key in the lock in time, the full monty). The embarrassment factor, which may well not be enough to deter a thief, is enough to put me off. It is possible to use it without the trembler alarm, just to go off if the cable is cut, though it is impossible to test this non-destructively, and the effectiveness is presumably reduced.

It claims to be ‘weather resistant’, but I don’t know how well it would survive heavy rain while parked in the open.

So, although I’ll persevere with it for the time being, I am suspicious of it, and am unconvinced that it would deter a brazen thief. And I am frightened of it!

David Earl