“ For maximum security. This disc alarm features an 18mm high-security four-way locking pin, reinforced carbide substructure. „
First thing to clear up is that the Xena XN18 disc-lock alarm has nothing to do with its Warrior Princess namesake. Although possibly the famous war-cry would be even more effective than the electronic alarm siren incorporated in this product.
As anyone with a motorcycle or scooter knows, theft or damage from attempted theft is a real and rapidly increasing risk. When I first rode motorcycles in the mid 1970s I never used a lock, alarm or chain yet my bike was never stolen or vandalised. In the less than six months since I returned to two wheels I have suffered wanton damage and an attempted theft from the communal garage despite fitting a cable lock. A sign of the times?
All this prompted me to purchase a top quality disc-lock alarm from Xena. Disc-locks can be bought cheaply of course but the security offered may be minimal. And every disc-lock carries the risk of forgetting it is in place, riding off only to smash your front brakes and probably fall off at the same time. Very expensive! Hence the reason for buying one with an alarm incorporated. If you do forget it, the alarm will go off as soon as you unlock the forks or the wheel begins to turn. Xena state that the alarm's sensitivity varies according to its position on the disc, more sensitive at the top, less sensitive at the bottom. However, on my bike (scooter) it only fits at the bottom, in the supposedly less sensitive position.
The XN18 is the top of the range model and therefore expensive (around £120 on the high street, but available much cheaper on the web). It is also heavy and I wouldn't like to drop it on my foot. Fitting to the disc takes a bit of a knack (I am still learning). If you don't get it on in less than about 5 seconds after it arms the alarm will go off (it arms/disarms automatically by the way). There is also a blue LED that flashes, but this is hard to see in daylight. At night (the riskiest time for theft) it is clearly visible though.
Physically the lock is extremely robust with a massive 18 mm locking pin and meets the highest industry standards (Thatcham, ART, Sold Secure, etc). A high security lock is fitted with three keys supplied (no replacements available, so don't lose them!). Shame no carrying case is provided though. Like all disc-locks you can get your hands dirty fitting or removing it. Also needs a bit of care when fitting to make sure you don't damage the disc surface (unlikely but possible). The finish is polished stainless steel and claims total resistance to corrosion.
A lock this size won't fit all bikes; there is a useful template available on the very good Xena website www.xenasecurity.com but my advice is try before you buy. It definitely fits the SYM GTS250 (my bike). If you have an idea which bike you would like to buy next, then check it against that too, or you could be left with a useless bit of kit. Actually not completely useless since this lock can also be used as an alarm padlock with Xena's own "Claw 18" disc-lock adaptor. Claimed battery life is 8 months and it takes a standard CR2 3V lithium battery. Replacement batteries and service kits are available from Xena. A small allen key is supplied with the lock, which you will need to replace the battery.
OK, so nothing will prevent a sufficiently determined thief (a tautology surely) but fitting one of these should deter the average ne'er-do-well and turn his attention to the next guy (or girl)'s pride and joy. I sure wish I had fitted it earlier.
Minor criticisms: could be even louder. The 110 decibel alarm is quite something in an enclosed space like a garage but noticeably less so out in the open. Perhaps there is a legal limit to avoid hearing damage; I'm not sure about that. Sensitivity seems to vary, sometimes I set it off just by locking the handlebar, other times I can move the handlebars quite sharply without doing so.