TMD’s Bluetooth bike lock adds sharing and alarm at a steep price
The €249 Chain Lock uses a phone as the key, but a Verge review found its convenience comes with cost and range tradeoffs.
By James Whitfield · Staff Writer
3 min read
TMD has brought its keyless security technology to bicycles with a Bluetooth chain lock priced far above many comparable analog locks. The product targets riders who want phone-based unlocking, digital sharing and insurance-friendly certification, but a Verge review found those benefits come with practical drawbacks.
The Netherlands-based company previously developed keyless systems for banks to control access to ATMs, according to The Verge. Its first bike product, the TMD Chain Lock, combines a hardened steel chain with a sleeve made from Dyneema and Kevlar fibers, which The Verge said makes it flexible enough to wrap around a seat post without scratching a bike.
TMD sells the lock from €229, with the reviewed version listed at €249, or about $283, according to The Verge. The review compared that with an ART-2 certified ABUS 8900 chain lock in a similar 110cm length, which it said costs about €60, or $68.
Phone unlocking and digital sharing
The lock uses Bluetooth proximity to detect an authorized phone. The Verge’s Thomas Ricker tested the 110cm model with an iPhone 15 Pro and said the lock recognized his approach on roughly 19 out of 20 attempts, allowing it to open with a press of its single button. When detection lagged, he reported a delay of no more than about a second.
The TMD app also lets owners grant access to friends or family, according to The Verge. That could allow another person to pick up a bike later without exchanging a physical key.
The same proximity feature created problems during testing. Ricker said the bike could be unlocked while it was parked outside a cafe because his phone remained within Bluetooth range. He reported a similar issue when the bike was outside his kitchen window, requiring him to move the bike or disable Bluetooth on his phone.
The lock can still be opened if the owner’s phone dies, according to The Verge. Users can enter a four-digit emergency code through repeated presses of the lock’s button, with a colored ring prompting each digit.
Certification, alarm and charging
TMD says the Chain Lock is resistant to conventional drilling and picking, The Verge reported. The lock has ART-2 certification from an independent Dutch testing organization; The Verge said many Dutch insurers require at least that rating for expensive e-bikes and cargo bikes. The app can generate a digital log for an insurer as proof the bike was locked, according to the review.
The lock includes a motion alarm rated at 100dB, which can be enabled through the app or with a double press of the lock button, according to The Verge. Ricker said the alarm was loud enough, though less harsh than expected, and shuts off after about 10 seconds without further movement.
Everyday sound was a complaint. The Verge measured the unlock tone at 75dB from one meter away, and TMD told the publication that a future software update will allow users to disable those sounds.
TMD claims up to nine months of battery life, according to the product specifications cited by The Verge. Ricker’s review unit fell 16 percent after one week, which he said suggested a shorter real-world span in his use because the lock was often near his phone indoors.
The Chain Lock charges through a proprietary magnetic pin connector rather than USB-C. TMD told The Verge it chose that design to reduce water and dust entry and leave more room for the battery and speaker. The lock is rated IP57, according to the specifications.
The Verge gave the TMD Chain Lock a score of 6 and said it is best suited to buyers who can afford the premium and strongly prefer keyless operation or digital sharing. For many riders, the review concluded, lower-cost certified chain locks will remain the more sensible choice.
This story draws on original reporting from The Verge.