Because any thief capable of packing the powertools necessary to remove a lock quickly is likely also capable of bringing a van, I’ve never really looked at disc locks as needing to provide much in the way of actual security. To me, they’re more effective as a deterrent, adding a visible layer to your overall security system that hopefully sends prying eyes on to an easier target. You can never make a bike 100 percent impervious to theft, but you can make it a less appealing target than the bike parked next to you.

Used like that, the addition of the motion sensor alarm is a master stroke. Elevating a minimal layer of security into something much, much more effective. It’s also why I opted to buy this cheapest of Xena’s new XX-range of disc lock alarms; it provides the same deterrent and alarm as more expensive models in a more compact, more portable, but less hard to remove package.

The XX6 will fit over pretty much any brake disc. Chain bikes to the one with the alarm, and they’re all protected; the motion sensor is sensitive enough to detect any real movements or anyone touching it, without going off every time the wind blows. That allows us to have an alarm along on road trips. No more trying to sneak bikes into a dodgy motel room in the Utah desert, 120db is more than enough to wake us up on the other side of that hollow wood door. Heck, I can hear it inside my house, three room and two doors away from where I keep my bikes.

It also adds an important layer of security at home. Thick chains locked to immovable objects provide great security, but I still want to know if someone’s messing with them. The Xena does that just as effectively as an on-bike alarm for way less money and, again, without hacking into the wiring loom or draining the battery. I put it on the wheel without a chain through it, making the bike that much harder to steal.