How many lumens do I need to be seen in daylight?

Enough to stand out as a flash: Focus's front beacon runs at 5000 lm and is visible from 2000 m. Visibility distance is a different measure from throw, so compare like with like.

How many lumens do I need to see at night?

Fewer than to be seen in daylight, if the beam is shaped. Focus's night low beam is 800 lm and lights the road 80 m ahead.

Is a 5000 lumen bike light too bright?

It depends on the mode. Focus uses 5000 lm for being seen, in its front beacon and high-beam flash, and 800 lm for its night low beam, which lights 80 m ahead.

Can Focus be used on a mountain bike?

Yes. Focus is designed for road riding and also fits a mountain bike, with a GoPro mount and a Garmin-style quarter-turn mount in the box.

How many lumens does a bike light need?

How many lumens a bike light needs depends on whether it has to let you see or let you be seen. Focus's 800-lumen low beam lights a dark road 80 m ahead, while its 5000-lumen front beacon is a flash visible from 2000 m. Beam shape decides how much of that light is useful.

Published 2026-11-11

A rider approaching at night on a dark street, a pool of white light on the asphalt ahead of the bike — Low beam at night: 800 lm lights the street 80 m ahead, against the 5000 lm the same light uses to be seen from 2000 m.

Lumens, throw and visibility: what the numbers mean

Lumen: The total light a lamp emits, in every direction. It says how much light leaves the lens, not where it lands.

Throw: How far ahead the beam usefully lights the road. Focus quotes it for one mode only, its low beam: 80 m.

Visibility distance: How far away other road users can see the light. Focus's 2000 m for its beacon and high beam is this measure, not throw.

Lumens to see at night versus lumens to be seen

Focus's four modes. Only the low beam's 80 m is throw, light on the road; 2000 m and 500 m are distances at which the light is seen.
Mode	Output	Distance	Runtime
Low beam, night only	800 lm	Lights 80 m ahead	6+ hours
Front beacon	5000 lm	Seen at 2000 m	20+ hours
High beam	500 to 5000 lm	Seen at 2000 m	—
Rear red	300 lm	Seen at 500 m	20+ hours

The same lamp uses 800 lm to light a road at night and 5000 lm to be noticed from 2 km. Seeing is a beam problem: the light has to land on the road ahead. Being seen is an output problem: the flash has to stand out against everything else in view.

Why beam shape matters as much as lumens

A round beam sends light up into oncoming eyes as well as down onto the road. A cut-off beam stops at a horizontal line, so its light stays on the road where the rider needs it.

The Focus bike light beside its clear clip-on lens on a white background — The StVZO lens comes in the box with every 55 g Focus and gives its beam a hard horizontal cut-off.

The lens takes its name from StVZO, the German regulation for road vehicles. Focus describes the lens and its cut-off; it does not claim German type approval.

What else decides whether a light works on a ride

Weight: 55 g for a 5000 lm light
Charging: USB-C, 80% in 15 minutes and full in 20
Sensors: 4, reading tilt, ambient light, movement and temperature
Mounts: a GoPro mount and a Garmin-style quarter-turn mount, both in the box
Operating temperature: −20 °C to +50 °C

Focus is designed for road riding and also fits a mountain bike. Off-road, being seen by traffic matters less than on the road, so the low beam's 80 m of light on the ground is the figure to compare.

Common questions

How many lumens do I need to be seen in daylight?: Enough to stand out as a flash: Focus's front beacon runs at 5000 lm and is visible from 2000 m. Visibility distance is a different measure from throw, so compare like with like.
How many lumens do I need to see at night?: Fewer than to be seen in daylight, if the beam is shaped. Focus's night low beam is 800 lm and lights the road 80 m ahead.
Is a 5000 lumen bike light too bright?: It depends on the mode. Focus uses 5000 lm for being seen, in its front beacon and high-beam flash, and 800 lm for its night low beam, which lights 80 m ahead.
Can Focus be used on a mountain bike?: Yes. Focus is designed for road riding and also fits a mountain bike, with a GoPro mount and a Garmin-style quarter-turn mount in the box.