The TMD Chain Lock is a keyless Bluetooth bike lock that unlocks as you walk up to it with your phone in your pocket, but at around 249 euros (roughly $283) it is a hard sell against analog locks that cost a quarter as much. Its strongest cards are insurance-friendly ART-2 certification and a tough, surprisingly flexible build, making it an intriguing but pricey gadget for committed cyclists.
What makes the TMD Chain Lock different
The lock pairs a Bluetooth proximity sensor and a motion alarm with a hardened steel chain wrapped in lightweight Dyneema and Kevlar fibers, so it stays strong yet flexible enough to coil around a seat post. It is built by a company that previously made keyless systems for bank ATMs, and that pedigree shows in the approach: your phone becomes a shareable digital key, handy for daily commuters who lock and unlock many times a day, or for households sharing one bike.
- Security rating: ART-2 certified, the level many insurers require
- Operation: keyless Bluetooth with a shareable digital key
- Alarm: motion-activated, 100dB
- Sizes: 70cm, 110cm and 160cm
- Battery: claimed up to 9 months, charged via a magnetic pin rather than USB-C
In testing with an iPhone 15 Pro, the lock recognised an approach roughly 19 times out of 20, reliable enough for daily use. The ART-2 rating matters because most Dutch insurers require at least that level to cover an expensive e-bike, and the companion app can generate a digital log proving the bike was actually locked, which can help with claims. For more gadget testing, see our reviews section.
The trade-offs of a keyless bike lock
Proximity unlocking is convenient until it becomes a liability. A bike parked close to your phone, such as just outside a window at home, can stay unlockable to anyone walking past, and a stolen phone could leave the bike exposed. The lock is also noisy: it emits a 75dB tone when unlocking, though TMD says a future software update will let owners mute the sounds.
There is no USB-C charging, so you are tied to the magnetic charging pin, and if the battery dies completely you can still open the lock with a four-digit emergency code tapped on the button. None of these are dealbreakers on their own, but stacked together they show that keyless convenience brings its own set of compromises. Browse more e-bike and accessory coverage in our EV section.
Should you buy the TMD Chain Lock?
For most riders, paying 249 euros when an ART-2 certified ABUS 8900 of similar length costs around 60 euros is very hard to justify on security grounds alone. The TMD does not lock your bike any more securely than far cheaper chains; what you are paying for is the keyless experience and the digital logging.
If you genuinely hate fumbling for keys, lock up dozens of times a day, or want to share access digitally, the TMD Chain Lock delivers, especially as the company plans matching U-Lock and ring-lock models that could all unlock together as one system. For everyone else, a traditional certified lock remains the smarter spend.
TMD Chain Lock: quick questions
How much does the TMD Chain Lock cost?
It sells for around 249 euros, roughly $283, which is about four times the price of a comparable ART-2 certified ABUS 8900 chain at around 60 euros.
Is the keyless bike lock secure enough for insurance?
Yes. It carries ART-2 certification, the level most Dutch insurers require for pricey e-bikes, and its app can produce a digital log showing the bike was locked.
