Bike lock: which security level to choose (U, chain, folding)

Theft is the leading cause of bike abandonment for commuting. Yet a good lock is not about absolute cost but about fit with bike value and zone risk. Here's how to choose without overpaying or underprotecting.

Lock types, from safest to weakest

The cable alone protects nothing: it cuts in seconds. It only serves to secure a wheel as a supplement.

Certification levels

Trust independent certifications rather than marketing: Sold Secure (Bronze/Silver/Gold/Diamond), ART (1 to 4 stars, reference in the Netherlands), or in France the SRA/2 wheel level. A Gold/ART 2+ lock resists serious attack; a Diamond/ART 3-4 targets high-value bikes and demanding insurance.

Budget based on bike value

Simple rule: dedicate 5 to 10% of bike value to the lock. A 3,000 € e-bike deserves a U or high-end chain; a 300 € bike gets by with a decent folding lock. Bike insurance often mandates a minimum certified level — check before buying.

The real technique: two locks

Thieves specialize by tool (bolt cutter, angle grinder, pry bar). Two locks of different technologies (a U + a chain) multiply time and tools needed — that's what discourages them. Always attach the frame + one wheel to a sealed fixed point, lock as high as possible (to prevent prying from ground).

Our recommendation

• Valuable bike / e-bike in city : U certified Gold/ART 2+ (frame + wheel) + chain for second wheel.
• Daily use, good compromise : certified folding lock.
• Never : cable alone.

Need help securing mechanics (battery, components) too or estimating value to insure? The L'Atelier assistant answers, and the estimate gives you your bike's real value.