The Kryptonite New York Diamond offers Sold Secure Diamond certification through a synthetic diamond coating that destroys angle grinder discs and a double deadbolt system requiring two cuts to bypass. bennetts.co.uk found the abrasive layer so effective it shredded cutting tools, while slowspinsociety noted this deters thieves by making attacks time-consuming. However, the lock weighs 5.07 lb, limiting portability for daily cycling use. Additionally, internal shackle dimensions are too small to fit over the front wheels of many motorcycles, restricting its utility as a sole lock for larger bikes. This high-security option fits stationary protection needs but is unsuitable for riders prioritizing lightweight convenience or universal motorcycle compatibility.
Full review
Synthetic diamond coating destroys abrasive discs
The defining feature of this lock is a synthetic diamond layer fused to the hardened steel shackle and body, engineered specifically to destroy angle grinder cutting discs. bennetts.co.uk found that standard 1mm abrasive discs tore through rapidly when attempting to cut the lock, with the reviewer ultimately giving up on the attack entirely because the material shredded their equipment. This coating appears as a bright, textured surface under microscopic inspection, resembling the edge of a diamond cutting disc itself. slowspinsociety noted that this design turns a theft attempt into a long, expensive job by making the effort so time-consuming and frustrating that thieves often abandon the target for an easier one.
The effectiveness of this coating extends beyond standard abrasive discs to include more specialized steel cutting discs used in professional-grade attacks. bennetts.co.uk recorded that even these high-quality diamond discs struggled significantly against the lock, taking serious work to make progress before eventually failing to penetrate the core material. The combination of a quality hardened steel shackle underneath and this disc-resistant outer layer creates a formidable barrier. While no portable lock is invincible, the New York Diamond raises the threshold for attack so high that it effectively neutralizes the most common power tool used by bike thieves.
Double deadbolt requires two cuts to bypass
Security is further reinforced by a hardened double deadbolt system integrated into the lock's design. slowspinsociety explained that because of this mechanism, an attacker cannot simply cut one side of the shackle and remove it; both sides must be severed to free the bike from the crossbar. This requirement doubles the time and effort needed for a successful attack, as each cut consumes more cutting discs due to the synthetic diamond coating's abrasive nature. The tight tolerance between the shackle and the body also prevents rattling while riding, which cyclingnews highlighted as a practical benefit that reduces wear on the locking mechanism over time.
This dual-cut requirement means that even if an attacker manages to breach one side of the shackle through sheer persistence, the lock remains anchored securely. bennetts.co.uk noted that this design choice complements the angle grinder resistance by ensuring that partial cuts do not compromise the entire security profile. The disc-style cylinder also adds protection against twist and pick attacks, though cyclingnews pointed out that picking is rarely a primary method for motorcycle thefts in real-world scenarios. The double deadbolt ensures that the lock's high security rating is maintained until the very last moment of an attack.
Internal dimensions exclude many motorcycle wheels
Despite its high security rating, the internal shackle dimensions of 213mm by 95mm present a significant limitation for motorcyclists. However, it did clear the narrower tires on a Kawasaki ZX-6R and Triumph Tiger. For larger bikes like the BMW GS, the lock can still be used by threading it through the wheel hub, per bennetts.co.uk, which offers excellent security but requires careful positioning during installation.
This size constraint means the New York Diamond cannot serve as a standalone solution for all motorcycles without additional tethering methods. bennetts.co.uk also discovered that the shackle's outer diameter of 25.8mm is too thick to pass through standard noose-end chains, such as an 11mm Pragmasis or Hiplok XL chain. To use it with a chain for added security, riders must trim sections of the rubbery coating off the shackle sleeve. Even then, only larger diameter chains like the 13mm and 16mm Pragmasis models can accommodate the modified lock, limiting compatibility options.
Manufacturing defects create inconsistent security
A significant controversy surrounds a batch of early production locks that suffered from a critical manufacturing defect. thebestbikelock tested one such faulty unit and found it could be cut through at the base of the shackle using only one angle grinder disc in just 13 seconds, completely negating its advertised security features. This flaw was attributed to an absence of the synthetic diamond anti-grinder material at the bottom of the shackle, leaving only a thin rubber cover exposed. The reviewer noted that many users have returned locks based on visual inspections of gaps or coating extent, but confirmed that the actual indicator of failure is simply missing protective material.
Subsequent testing by thebestbikelock and slowspinsociety suggests that Kryptonite has addressed this issue in newer production runs. thebestbikelock tested five additional locks after the initial faulty unit and found them all to perform exceptionally well, with cutting times ranging from several minutes to requiring over ten discs per side. slowspinsociety advised that buyers purchasing new units from reputable shops should be safe from these defects, as the problematic batch was distributed over a year prior to recent reviews. The inconsistency in build quality remains a concern for those buying used or older stock.
Heavy weight limits daily portability
At 2.36 kg (5.07 lb), the New York Diamond is substantially heavier than standard U-locks, making it cumbersome for riders who need to carry their lock frequently. cyclingnews described the lock as heavy duty and noted that its weight takes some getting used to, particularly for cyclists prioritizing low bike weight or quick convenience stops. The substantial mass provides a sense of robustness but adds noticeable burden during rides, especially on lighter bicycles where every gram counts.
The weight also impacts how the lock is mounted and carried in practice. bennetts.co.uk found that while it comes with a cycle carrier bracket, removing the clamp reduces the weight slightly to 2.36 kg, though this does not significantly alleviate the carrying challenge. For motorcyclists, the lock can be stored on a van rack or luggage system for overnight security, as slowspinsociety suggested, but daily commuters may find it too bulky for casual use. The trade-off between maximum security and portability is stark, catering more to stationary protection than active riding convenience.
Awkward mounting brackets risk frame damage
The included mounting bracket for attaching the lock to a bicycle frame has drawn criticism for its design and installation process. cyclingnews reported that Kryptonite's brackets are awkward to fit and can damage paintwork if not installed correctly or if subjected to stress during removal. The tight tolerance of the shackle, while beneficial for security, also makes locking the bike at odd angles difficult, requiring precise alignment with the anchor point.
Users must exercise caution when securing the lock to their frame, as improper handling could lead to scratches or chipping on high-value bicycle finishes. The bracket's complexity adds another layer of friction to an already heavy and cumbersome security solution. For riders who prioritize ease of use and quick access, these fiddly traits may outweigh the benefits of the highest security rating available.
Strengths
- +Synthetic diamond coating provides exceptional resistance to angle grinder attacks, tearing through abrasive discs rapidly.
- +Holds Sold Secure Diamond rating and Kryptonite's highest security certification for bicycles and motorcycles.
- +Features a hardened double deadbolt system that requires two cuts to free the lock from its crossbar.
- +Includes a sliding dust cover over the keyway to protect internal mechanisms from dirt and debris, per Cyclingnews.
Watch-outs
- −Weighs approximately 2.36 kg (5.07 lb), making it heavy for daily carrying or lightweight cycling use.
- −Internal shackle dimensions are too small to fit over the front wheels of many motorcycles, limiting its utility as a sole lock.
How it compares
With a Sold Secure Diamond rating and synthetic diamond coating, the Kryptonite New York Diamond offers superior angle-grinder resistance compared to all other products in this list, including the Litelok models. However, it is significantly heavier (5.2 lb) than the KryptoFlex 710 (1.15 lb) and has smaller internal dimensions that may not fit larger wheels or frames as well as the extended-shackle Litelok X1 Plus.
Rating sources
Our 3.7 score is the average of the 5 scored reviews above; 3 more reviewed it without printing a score and are not in the average. More about methodology.
