LightingBikeSafety

Bike lights: lumens, runtime and regulations explained

Max

|6 minAugust 19, 2026

Bike lights: lumens, runtime and regulations explained

Seeing or being seen: two different needs

The classic mistake: buying a single "powerful" light. In reality, bike lighting serves two distinct purposes.

Purpose	Front	Rear
Being seen (lit town)	50-100 lm	15-30 lm
Seeing (unlit road)	400-1000+ lm	30-50 lm

## Lumens: the right ballpark

Town: 80 lm front is enough to be visible; no need to dazzle.
Suburban / paths: 200-400 lm to distinguish obstacles.
Dark road / night MTB: 800 lm and above, with a wide beam.

At the rear, a 30 lm flashing light catches the eye from a distance. Favour an "eco constant" mode in town (flashing interferes with distance estimation) and a flash mode on the road.

Battery life: read the table, not the marketing figure A light claiming "20h battery life" announces it on mini mode. On full beam, the same often drops to 1h30-2h. Calculate based on your actual route and recharge regularly. A rear light cutting out at night is a real hazard.

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## Regulations (France)

Front light white or yellow + rear light red, non-flashing for homologation (flashing is tolerated as a supplement).
Reflectors mandatory (rear red, pedals, wheels).
High-visibility vest mandatory outside built-up areas at night.