Disclosure: As an Amazon Associate, we earn from qualifying purchases. If you click a link on this page and make a purchase, we may receive a small commission at no extra cost to you.
A disc lock needs to do more than make your motorcycle harder to roll away. It also needs to fit your brake rotor, stay manageable enough for daily use, and avoid becoming a nuisance when you carry it. The Kryptonite KryptoLok Alarm Disc Lock, model 004776 and identified in its manual as the KryptoLok 6A, combines a 6mm locking pin with a motion-triggered 120dB alarm. Its compact design and selectable alarm mode are useful strengths, but its 6.5mm rotor-thickness limit means you should check fit before buying.
Quick Verdict
Rating: 8/10
Best For: Riders who want a compact brake-disc lock with an audible motion alarm for everyday parking.
Bottom Line: The 120dB alarm, weather-protected electronics, selectable alarm mode, and compact 78 x 54mm body make this a practical extra security layer. The main tradeoff is compatibility, because the 6mm pin is intended for rotors up to 6.5mm thick and the lock does not anchor your motorcycle to a fixed object.
| Specification | Detail |
|---|---|
| Brand | Kryptonite |
| Model | KryptoLok Alarm Disc Lock, model 004776 |
| Product type | Alarmed brake-disc lock |
| Alarm | Built-in 120dB alarm system |
| Locking pin | 6mm |
| Rotor compatibility | Rotor thickness up to 6.5mm, with a suitable vent hole or open slot |
| Body | Zinc diecast construction |
| Dimensions | 78 x 54mm |
| Electronics | Weather-proof electronics module |
| Battery | Replaceable 900mAh CR2 lithium battery |
| Battery life | About one year estimated; manual states roughly 8 to 12 months with normal use |
| Alarm modes | Alarm armed or alarm deactivated for transport |
| Keys | Two stainless-steel keys |
| Warranty | Two-year limited electronic warranty and lifetime limited mechanical warranty for the original user, subject to Kryptonite’s terms |
Key Takeaways
- The built-in 120dB alarm adds an audible response when continued movement or excessive vibration is detected.
- The compact lock uses a 6mm locking pin and is specified for brake rotors up to 6.5mm thick.
- A zinc diecast body surrounds a weather-protected electronics module for regular outdoor use.
- You can lock the disc with the alarm armed or deactivated, which is useful when transporting the lock.
- The replaceable CR2 battery is rated for roughly 8 to 12 months of normal use, although frequent alarms and cold temperatures can shorten that period.
What Is the Kryptonite KryptoLok Alarm Disc Lock?
The Kryptonite KryptoLok Alarm Disc Lock is a compact motorcycle brake-disc lock that combines a physical locking pin with an electronic motion alarm. Kryptonite lists it as model 004776, while the instruction manual refers to it as the KryptoLok 6A Alarm Disc Lock.
Instead of wrapping around the wheel or attaching the motorcycle to a post, the lock slides over the brake rotor and places its 6mm pin through a suitable vent hole or slot. This prevents normal wheel rotation while the lock is installed. The alarm provides a second deterrent by responding to movement or excessive vibration.
Its main advantage is portability. At 78 x 54mm, it takes much less storage space than a full chain-and-padlock setup. That convenience comes with an important limitation: a disc lock is an additional security layer, not a physical anchor to a fixed object.
Who Should Buy It?
Best For
- Motorcycle or scooter owners who want compact security for everyday stops.
- Riders who value an audible motion alarm in addition to a physical disc lock.
- Buyers whose brake rotor is no more than 6.5mm thick and has a usable hole or slot.
Skip If
- Your brake rotor is thicker than the stated 6.5mm limit or lacks suitable clearance.
- You need a lock that physically anchors the motorcycle to a fixed object.
- You do not want to maintain a battery-powered alarm system.
Before You Buy: Check your rotor thickness, vent-hole size, and surrounding clearance. The 6mm pin is specified for rotors up to 6.5mm thick, but the lock still needs a suitable opening and enough room to slide onto your particular brake disc.
Alarm Performance and Controls
The headline feature is the 120dB alarm. According to Kryptonite’s instructions, motion or excessive vibration first produces warning beeps. If movement continues, the lock progresses to louder warnings and then activates its 120dB siren for about 10 seconds. Continued movement can trigger the sequence again.
This stepped response is useful because the lock does not immediately launch into a full siren after every small movement. It gives an audible warning before the full alarm sequence, while continued interference produces the stronger response.
You can also lock the disc without leaving the alarm armed. Kryptonite’s manual explains that there is no simple external on/off switch. Instead, the locking sequence lets you choose the alarm state by listening for the confirmation beeps. One beep indicates the alarm is activated, while two beeps indicate it is deactivated.
Materials and Build Quality
The lock uses a zinc diecast body with a 6mm locking pin. Kryptonite describes the electronics module as weather-proof, which is important for a motorcycle security device that may see rain, road moisture, and changing temperatures.
The 78 x 54mm body is compact enough to make the lock practical for repeated use. It is easier to store than a large chain, but you should still give it a dedicated place in your luggage or storage compartment so it cannot move around and accidentally arm during transport.
The product includes two stainless-steel keys. Kryptonite also supports its Key Safe program, which is useful if you register your key details and later need replacements under the program’s current terms.
Installation and User Experience
Using the lock does not require permanent installation. You first identify an accessible vent hole or open slot in the front or rear brake rotor. Kryptonite notes that a vent hole can provide less movement around the locking pin than a larger open slot.
You then insert and turn the key, remove it, slide the lock over the brake disc, and press the cylinder down. The audible confirmation tells you whether the alarm is armed or deactivated. When correctly seated, the cylinder clicks into the locked position.
The process is simple once you learn the beep pattern, but your first few uses deserve extra attention. Confirm that the lock is actually engaged and that you understand which beep pattern corresponds to the alarm setting you want.
Pro Tip: Before relying on the lock away from home, practice locking it once with the alarm armed and once with the alarm deactivated. This helps you recognize the confirmation beeps and reduces accidental alarms during transport.
Battery Life and Maintenance
The alarm uses a replaceable CR2 lithium battery. Kryptonite estimates about one year of battery life, while its current manual gives a more specific normal-use range of roughly 8 to 12 months. Frequent alarm triggering and extreme temperatures, especially colder conditions, can shorten battery life.
The manual states that a low battery is indicated when the lock begins to chirp. Because the alarm is part of the product’s security function, replacing a weak battery promptly makes more sense than waiting for the alarm to stop functioning reliably.
For the mechanical cylinder, Kryptonite recommends periodic lubrication with a silicone- or Teflon-based lubricant. Its manual specifically advises against using WD-40 as the cylinder lubricant.
Compatibility and Safety
Fit is the first safety check. The 6mm pin is designed for a brake rotor up to 6.5mm thick, but rotor thickness alone does not guarantee compatibility. The pin also needs to pass through a suitable hole or slot without interfering with nearby brake components.
The 120dB alarm is intentionally very loud. Kryptonite warns against placing the alarm close to unprotected ears and advises that children should not play with the alarm lock. The manual also says not to use the alarm near pets.
Never attempt to ride with a disc lock still attached to the rotor. A visible reminder routine, such as always placing your key or riding gear in a way that reminds you to remove the lock, can help prevent an expensive mistake.
How It Performs in Real Use
For Short Everyday Stops
The compact body and push-down locking action suit frequent stops where you want something faster to deploy than a heavy chain. The 120dB alarm adds attention if someone continues moving or disturbing the motorcycle.
For Longer Parking Periods
The KryptoLok can add another layer of security, but it does not attach your motorcycle to a fixed structure. For higher-risk or long unattended parking, a disc lock makes more sense as part of a layered setup rather than your only physical security measure.
For Transport
Kryptonite specifically provides an alarm-deactivated mode for transport. This matters because vibration inside luggage or a motorcycle storage compartment could otherwise cause unwanted alarm activity. Confirm the deactivated beep sequence before packing the lock.
For Cold-Weather or Frequent Use
You may need to watch the battery more closely if the lock is frequently triggered or regularly exposed to cold temperatures. Kryptonite states that both conditions can reduce the normal 8 to 12-month battery-life range.
Common Mistakes to Avoid
- Buying without measuring: Confirm that your rotor is within the 6.5mm thickness limit and has a compatible opening.
- Forgetting the alarm mode: Learn the one-beep and two-beep confirmation before regular use.
- Transporting it armed: Use the alarm-deactivated mode when vibration during transport could trigger the siren.
- Ignoring battery warnings: Replace the CR2 battery when the lock signals that power is low.
- Treating it as an anchor: The lock blocks the brake disc, but it does not secure the motorcycle to a fixed object.
Pros and Cons
Pros
- Built-in 120dB motion-triggered alarm system.
- Compact 78 x 54mm zinc diecast body.
- Alarm can be armed or deactivated for transport.
- Weather-protected electronics module suits regular outdoor use.
- Replaceable CR2 battery and two stainless-steel keys are included.
Cons
- The 6.5mm rotor-thickness limit means it will not fit every brake disc.
- A disc lock does not anchor your motorcycle to an immovable object.
- The electronic alarm adds battery maintenance and can sound unintentionally if transported while armed.
Is It Worth the Price?
The KryptoLok Alarm Disc Lock sits in the practical middle ground between a basic mechanical disc lock and larger, more elaborate alarmed motorcycle-security hardware. You are paying for the combination of a compact physical lock, selectable alarm function, 120dB siren, weather-protected electronics, and replaceable battery rather than for a simple metal pin alone.
It offers the strongest value when you want a small lock that is quick to carry and adds an audible warning to your parking routine. It is less compelling if your main goal is maximum physical resistance or the ability to anchor the motorcycle to street furniture, a ground anchor, or another fixed point.
How It Compares to Alternatives
The ABUS Detecto 7000 RS1 is a more substantial alternative with a 100dB alarm, hardened-steel structural components, 3D position detection, and a system that automatically re-arms after its alarm cycle. It may appeal more if you want a more feature-heavy alarmed disc lock and do not mind a different size and design.
The Oxford Screamer 7 uses a 7mm locking pin and a 110dB siren with motion and shock sensing. The Kryptonite stands out with its louder stated 120dB alarm and compact 78 x 54mm format, while your rotor dimensions should ultimately determine which pin size and body shape fit correctly.
Frequently Asked Questions
Is the Kryptonite KryptoLok alarm always active when the disc is locked?
No. Kryptonite allows you to lock the disc with the alarm armed or deactivated. The manual uses confirmation beeps to identify the selected state, with one beep indicating alarm activation and two beeps indicating alarm deactivation.
Will the 6mm locking pin fit my motorcycle?
Kryptonite specifies the 6mm pin for rotors up to 6.5mm thick. You also need a vent hole or open slot that accepts the pin and enough surrounding clearance for the lock body, so measure your brake disc before ordering.
How long does the battery last?
Kryptonite markets the battery life at about one year. Its current manual gives an expected range of roughly 8 to 12 months under normal use and notes that frequent alarm triggering or extreme temperatures can shorten battery life.
What battery does the Kryptonite alarm disc lock use?
It uses a replaceable CR2 lithium battery. Kryptonite specifies a high-capacity 900mAh CR2 battery, and the instruction manual lists the battery among the included components.
Is the lock waterproof?
Kryptonite describes the electronics module as weather-proof and fully protected. That supports normal outdoor exposure, but it should not be interpreted as permission to submerge the lock or ignore the battery-compartment seal.
Can this replace a chain or ground-anchor lock?
Not if your goal is to physically attach the motorcycle to a fixed object. The KryptoLok blocks rotation at the brake disc and adds an alarm, so it is better viewed as one layer in a broader security setup for higher-risk parking.
What warranty does Kryptonite provide?
Kryptonite’s current manual lists a two-year limited electronic product warranty and a lifetime limited mechanical product warranty for the original user. Batteries are excluded from the electronic warranty, and complete eligibility depends on Kryptonite’s current warranty terms.
The Bottom Line
The Kryptonite KryptoLok Alarm Disc Lock is a strong fit for riders who want a compact disc lock with a loud 120dB alarm, selectable alarm mode, replaceable CR2 battery, and weather-protected electronics. You should skip it if your rotor exceeds the stated 6.5mm thickness limit or if you specifically need a lock that anchors your motorcycle to an immovable object.
Its biggest strength is the useful combination of portability and audible deterrence. Its biggest limitation is the same one shared by this style of security device: correct rotor fit is essential, and a disc lock should not be mistaken for a fixed-point security system.
