In the world of bike security, few products have sparked as much debate as TMD's new Chain Lock. Touted as a keyless, smart alternative to traditional bike locks, it arrives with a price tag of €249 (about $283) — roughly four times the cost of a comparable high-end analog lock. But for those who hate carrying keys, lock a bike multiple times daily, or need insurance-approved security for an expensive e-bike, the premium may be justified.
What makes the TMD Chain Lock different?
TMD, a company originally known for securing ATMs for banks, has translated its keyless access technology into the bicycle market. The lock replaces a physical key with a Bluetooth proximity sensor that communicates with a smartphone app. When the phone is nearby, the lock can be opened with a single press of a button. This eliminates the need to fumble with keys — a convenience that adds up for urban cyclists who lock and unlock their bikes dozens of times per day.
The lock itself consists of a hardened steel chain wrapped in a sleeve made of Dyneema and Kevlar fibers. This combination makes it both strong enough to resist cutting and flexible enough to be wrapped around a seat post while riding. The chain comes in three lengths: 70cm, 110cm, and 160cm, with weights ranging from 1.3 to 2.1 kilograms. The sleeve also protects the bike's paint from scratches — a small but appreciated detail.
Security features and certification
TMD's Chain Lock has earned an ART-2 certification, a rating issued by an independent Dutch organization that tests bike locks on a scale of one to five. Most Dutch insurance companies require at least ART-2 to validate policies on expensive e-bikes and cargo bikes. This certification is comparable to Sold Secure Silver or Gold in the UK, 2 Roues in France, and VdS approval in Germany. In the United States and Canada, no centralized independent testing body dictates insurance requirements, but the lock's robust construction still offers strong physical protection against bolt cutters, saws, and leverage attacks.
The lock also features a 100dB motion alarm that activates when the lock is jostled. The alarm automatically turns off after 10 seconds of inactivity. While not ear-piercing, it is sufficiently loud to deter opportunistic thieves and alert nearby pedestrians. The alarm can be armed or disarmed via the app or with a double press of the lock's button.
Day-to-day convenience and drawbacks
During testing, the lock performed reliably about 95% of the time, seamlessly unlocking when the phone approached. However, convenience comes with tradeoffs. Because the lock relies on Bluetooth proximity, a bike parked within range of the phone — such as outside a café window or next to a kitchen — automatically remains unlocked, allowing anyone to walk up and take it. This forces the user to either move the bike, turn off Bluetooth, or manually lock the device via a separate emergency code.
The lock emits a 75dB tone every time it unlocks, which can draw unwanted attention to the bike. TMD has promised a future software update to allow users to disable this sound. Additionally, the lock's battery life is rated at nine months, but real-world testing suggests it may last only six to seven weeks if the bike is stored indoors within Bluetooth range of the phone. Charging is done via a proprietary magnetic pin connector rather than USB-C, which TMD says is for better water and dust sealing (IP57). A dead lock can be revived after two to three minutes of charging, but the proprietary cable is a potential point of failure.
Sharing and emergency access
The lock can be shared with friends and family through the TMD app, allowing multiple people to unlock the bike with their own phones. This is useful in bike-sharing scenarios, such as when a friend needs to pick up a bike from a train station. If the phone is lost or stolen, the bike becomes vulnerable — but TMD has included a backup emergency code system. A four-digit code can be entered using the lock's single button, with the ring changing color to indicate each digit. The app also maintains a log file that can be used as proof of locking for insurance claims.
Value proposition: Is $280 too much?
The most direct competitor to the TMD Chain Lock is the ABUS 8900, an ART-2 certified chain lock in the same 110cm length, which retails for approximately €60 ($68). The ABUS lock uses a traditional key, but it offers comparable physical protection. The TMD lock's advantages — keyless convenience, digital sharing, and a motion alarm — come at a steep premium. For cyclists who lock their bikes only once or twice a day and do not mind carrying a key, the ABUS is clearly the better value. However, for commuters who lock their bikes a dozen times daily, the friction of keys can be significant. In cities like Amsterdam, where bikes are used for everything from commuting to grocery shopping, the convenience of a keyless lock may be worth the extra cost.
TMD has also announced plans to release an "anti angle grinder" U-Lock and a GPS-equipped ring lock, which could later work together with the Chain Lock to create a fully integrated keyless system. This ecosystem approach could further justify the premium, especially for owners of high-end cargo bikes or e-bikes worth several thousand dollars.
Background: From ATMs to bicycles
The idea of using keyless technology for locks is not new, but TMD's origins in banking security lend it credibility. The company developed a centralized keyless system for banks to authorize service access to ATMs, replacing physical master keys that created security risks when lost or stolen. This same technology now powers the bike lock, with the phone acting as a digital key that can be instantly revoked or shared. While the bike lock market is crowded with smart locks from startups, TMD's experience with high-security environments may give it an edge in reliability and software reliability. However, the company is a newcomer to the consumer cycling world, and long-term durability remains to be seen.
The increasing popularity of e-bikes, which often cost $3,000 to $10,000, has driven demand for higher-security locks. Insurance companies in Europe increasingly require certified locks for theft coverage, and smart locks that provide digital evidence of locking are becoming more accepted. The TMD Chain Lock's ART-2 certification and app-based log file align with this trend.
Yet the lock's noisy operation and proximity issues highlight the challenges of smart locks that must balance convenience, security, and user experience. Competing products, such as the Seatylock smart lock or the Kryptonite Evolution series, offer different trade-offs — some with fingerprint sensors, others with physical keys. The market has yet to produce a clear winner.
For now, the TMD Chain Lock is a solid but niche product. It excels in scenarios where keyless convenience is paramount and the budget is generous. For everyone else, a €60 ABUS lock is more than adequate. As TMD expands its ecosystem and refines its software, future iterations may address the noise and proximity issues. But at present, the lock remains a $280 solution to a $60 problem — albeit a well-engineered one.
Source:The Verge News