Wheel theft is always a risk when leaving a nice bike parked in an urban environment. Cyclists can do things like removing the front wheel and locking it to the frame and rear wheel, or carrying multiple locks. Kryptonite's new Security WheelNutz, however, offer a quicker and lighter alternative ... with an interesting twist.

WheelNutz are installed on the ends of the front wheel axle, in place of the existing nuts or quick-release hardware. To remove that wheel, you just loosen them off like regular wheel nuts, but with one exception – they'll only release if the bike is upside down.

This means that as long as the bike is locked in such a way that it can't be turned over, its front wheel can't be removed. One regular lock can then just be used to secure the frame and rear wheel to a nearby immovable object.

Kryptonite's Security WheelNutz are available now, priced at US$30.95 a set.

Other add-on wheel-locking devices we've seen recently have included the quick-release-lever-securing Quick Caps, the mini combination lock-like Sphyke C3N, and the infiniti3D system, which only releases with a user-specific key.