Good disc locks are massively armored devices that are virtually impervious to bolt cutters and other forms of devious mischief. Most versions of disc locks have keyed pins that lock through one of the holes in the front brake disc.
Parked motorcycles are vulnerable. A thief with any knowledge of motorcycles can put a bike in neutral and roll it onto a trailer or into a truck bed. There are two things that can make this harder. First, virtually every street bike and most modern dual-sports have steering locks. Unfortunately, even motorcycles with the steering locked can still be rolled. To prevent rolling, something else needs to be done. That protection can come in the form of a brake disc lock.
When properly installed and locked, brake disc locks prevent forward or backward movement of a motorcycle because the lock cannot pass the fork leg or brake caliper. When combined with the motorcycle’s steering lock, a disc lock makes it virtually impossible to move a bike without lifting.
First, it is important to make sure that the device is actually locked. This can sometimes be a challenge since most locks have a concealed locking pin that must be guided through a small disc hole.
The other imperative is that you MUST remember that you used the disc lock. Many riders have damaged either the brake disc, brake caliper, or the fork tube by trying to ride off with the lock in place. One good way to prevent this is to use a tether or some other form of visual alert that the disc is in place. There is an added bonus to the use of the alert. It also tells a potential thief that a lock is in place. This may just serve as a preemptive deterrent.
Kryptonite KryptoLok DFS 10
This lock is the most traditional style of disc security, and the type that I use personally. It is constructed of heavy drop forged steel (DFS) that resists cutting, sawing, freezing or chisel attacks. The sheer size of the “U” portion of the lock makes any assault with a bolt-cutter futile. The push-through pin is completely concealed when locked through the disc hole. A nice feature of this Kryptonite lock is that it has lifetime key registration and replacement. MSRP $44.
Kryptonite New York Disc Lock
Another fine offering from the Kriponite folks, the New York is a yoke-style lock. It has a 1/2" kryptonium steel shackle that feeds through the larger area inside that disc circle (rather then the holes like the previous lock). The crossbar contains an anti-pick disc style cylinder with double dead bolt lock. This model includes a carrying pouch and disk lock reminder cable. MSRP $65.
Xena XR1 Brake Disc Lock with Alarm
This lock is a traditional styled lock (like the KryptoLock) with the added feature of an alarm. It has dual shock and movement sensors that sound a 110db alarm if activated. Some early alarm discs had alarms that were of such a low volume as to be ineffective. However, 110db is equivalent to an industrial power-saw. That is certainly loud enough to garner attention. The battery life is claimed to be 8 months. MSRP $80.
OnGuard Boxer Pin Disc Lock
This lock features a pin that fits into the locking mechanism. The style may fit some hard to reach applications that other styles can’t. However, it also seems to leave more of the pin exposed. The Boxer is constructed of armored hardened steel and special titanium plating. It includes 5 laser cut keys and 1 light key. MSRP $25.
Final Thoughts On Brake Disc Locks
For well under $100, a disc lock is a formidable theft deterrent. It is also a device that will fit easily under most seats for convenient use. Buy one and use it.