Bike light manufacturers can put any 'lumens rating' on their product that they want. There is no governing body out there that states that they have to measure or be truthful about what they claim their light output to be. What many of them do is read the LED spec that they are using, get that LED's max rating and multiply by the number of them that they are using and voila, magic lumen number.

The problem is that number is a best case and impossible number. The real output is somewhere below that. The reasons for lower output are:
  • Heat dissipation - as the LED gets hot, it gets dimmer to protect itself
  • Power source - if the power source is not at the perfect voltage, it gets dimmer
  • Reflector light loss - the mirrors on glass on a light will result in some light loss
  • LED Binning - all LEDs at birth are sorted for their brightness. So all LEDs of the same model are not equal
That's why Mtbr works so hard to demystify LED output. The ultimate test is using an integrating sphere to measure light output. This piece of equipment costs about $20,000- $100,000 to purchase and requires a trained technician to operate. This year, Mtbr is using the integrating sphere of Light and Motion and Lezyne to measure lumen output. We are present during all measurements and we will cross-check their work with each other.

To complement these lumen measurements, please check our Beam Pattern Comparisons of these lights.

Lumen measuring process using an integrating sphere with Chris McCaslin.

As you can see, it is not a simple process and that is why so many light manufacturers do not measure their output. There are very few independent labs around this country too that can do this work.

We realize of course that Light and Motion is a manufacturer and they are testing competitors' lights. But we have evaluated their process and were present during testing. Furthermore, we are double-sourcing this year by testing at another manufacturer called Lezyne and cross-checking their work. We have already compared four lights that they each measured and the results match up within 1-2%. Finally, this is just a piece of our lights testing and is supplemented by our own Mtbr Lux lab testing and light beam image data.

These lumen readings were recorded 31 seconds after the light was turned on. This is according to the FL-1 Flashlight Standard that specifies lumen measurements to be recorded 30 seconds after the light is turned on. The FL-1 Flashlight Standard was created so manufacturers have a standardized method of measuring lights and making claims such as brightness and waterproofing. Some light companies are using the FL-1 standard and fighting for its use in the bike light industry. Learn more about the FL-1 Flashlight Standard HERE.

Lumen Test Results


Numbers in red color are approximated from Mtbr Lux

Mtbr further supplements this Lumen testing with: Pattern Shots
Mtbr Lux measurements
Riding Impressions for each light

We created a few graphs for you to make light comparison easier.

2013 Claimed vs Measured Lumens

This first graph is a bar graph of each light's lumen output. Taller bars indicate a brighter light. The cheaper lights are on the left and the most expensive ones are on the right. And the best feature of this graph is it has the red dots on each bar that mark a light's 'Claimed Lumens'. This makes it very easy to compare what a light claims and what we measured its lumen output to be.


2013 Lumen per Dollar

This next graph is our measured lumens divided by the price of the light. Higher numbers indicate a brighter light for the money.


2013 MTBR Lux vs Lumen

This graph compares the Mtbr Lux metric in our very own lab and compares it to the integrating sphere readings. This map shows that the Mtbr Lux reading is always consistent and proportional with lab measured integrating sphere data. This validates the Mtbr Lux readings which we have used for the last 5 years. This means that we can compare these new crop of lights to all our historical data. And in cases were we can't measure with an integrating sphere, we will always have Mtbr Lux readings.


Related Links
All Mtbr Lights Shootout Articles »
2013 Bike Lights Shootout »
2013 Backyard Beam Pattern Comparisons »
2013 Mtbr Lux measurements »
2013 Mtbr Lumen Tests »
2012 Bike Lights Shootout »
Mtbr Lights Reviews »
Mtbr Lights Forum »

SPECIAL NOTE: Cygolite has declined to participate at this point. Niterider, Exposure, Jet Lites and Gloworm are all sending new lights asap. If you would like to send lights for this test, please email [email protected]