Wednesday, 07 August 2019 / Published in Updates

Recently an article came out in Consumer Reports about LED headlights on cars, and as a lighting engineer it was frustrating to read due to the misconceptions and myths that are perpetuated by it. So thought I would take some time to point out the issues. Even though this doesn’t really have anything to do with traditional bike lights, the concepts are the same!

https://www.consumerreports.org/headlights/led-headlights-can-be-brighter-but-often-lack-clear-advantages/

 

The headline for the post is “LED Headlights Can Be Brighter but Often Lack Clear Advantages.

The main argument being made in the article is that the light source themselves are the key to whether a headlight is bright enough, which couldn’t be further from the truth. There is a lot that goes into a successful headlight, and CR’s testing methods are also quite questionable.

 

LED Headlight Design Requirements

Let’s first go over what a lighting engineer has to work with when starting a new design from scratch. This applies both to vehicle headlights, and bike lights. There are several criteria that is often evaluated.

  • How many lumens to work with.
    • This is defined mostly by how quickly and effectively heat can be wicked away from the LED source. In automotive headlights there are large heatsinks that are often passive, although some headlights use internal fans to have air rushing over there to pull heat away.
    • In bike lights, this is often defined by the size of the headlight in a well engineered light. It is easy to put 2000 lumens in a tiny matchbox size light, but the second it’s turned on and being used for more than 30 seconds it will overheat, and pull power to save itself. Rendering it more like a 500-600 lumen light.
  • Beam pattern requirement
    • This is often defined internally by the OE manufacturer. They will have a set of requirements for lighting targets to hit at certain points in the beam pattern. Some manufactures value beam width over center intensity, others focus more on downrange intensity. Lots of simulation and testing goes into defining these targets.
    • For bike lights, we do something similar where we ride our favorite trails, and make note of where and how much light we would like to see in a system.
  • Cost targets
    • Pretty obvious one, but it constrains the lumen requirements. The LED chips themselves are not cheap, and in order to get higher lumen numbers need more supporting systems such as fans or larger heat sinks.
  • Styling
    • There are a few methods of LED lighting for automotive that are used to create the beam pattern, but usually different styling requirements drive this.

 

The main portion of a lighting engineers development comes from the beam pattern. With software such as Lucidshape we can shape the light to create specific beam patterns. With LED’s it is actually easier to control the lighting then with Halogen or HID bulbs because the actual emitting source is smaller.

 

LED’s can’t shine down the road?

The myth of “LED’s can’t shine further down the road” is the one that is the most frustrating. The ONLY thing that matters about the source of light, is the lumens and the color. It is the reflector design that determines how far you see down the road or how wide the beam pattern is.

The Trail Edition and the Road Edition are good examples of this.

 

Both use the exact same LED chip, the exact same driver setup, and the exact same castings. The only thing different is the reflector. The Trail Edition is optimized for beam with and even illumination, while the Road Edition offers nearly twice the “punch” at the expense of less width. Each one designed for each specific task.

Automotive headlights are similar. OE Manufacturers optimize their headlight for the majority of customers. European and Japanese headlights tend to focus more on low beam width and even illumination since European and Japanese drivers find themselves in city centers more often. They also tend to use the high beam far more often. Interestingly enough North American drivers do not use the high beams very often, even in situations where they should be. For that reason a lot of domestic OE’s have low beams that have more center punch, and seem “brighter” in these tests that Consumer Reports does.

 

 

Tuesday, 30 July 2019 / Published in Updates

There are lots of different styles of bike riders. Gravel, singletrack, bike pack, road, endurance, commuter, downhill, recumbent, and a dozen others. Each type of riding comes with some unique lighting demands so we decided to put together a quick guide for the major types of riding and what lights suit it best.


Road Riding
This one is easy. If you find yourself riding exclusively on the road whether you are a commuter, weekend warrior, or doing overnight endurance events then the Road Edition is going to be the best light for you. The reason for this is due to the cutoff line that the Road Edition has, this StVZO compliant cutoff means that you can aim your light to get the maximum brightness on the road, without blinding oncoming traffic.

Nearly every bike light sold in the USA is a circular beam pattern or a wide flood, so one of the very common pieces of advice found on forums and discussions is to aim the light down. This puts the brightest part of the light in front of your tire instead of aiming down the road. Cutoff line optics are like the low beam on your car and are designed to put light on the road without blinding traffic.

These cutoff or StVZO lights are very common in Europe since several countries require it by law for any riders using lights on the street. We hope that more riders in the USA will learn about these cutoff line style lights and adopt them on their own bikes.

For endurance riders doing more than 4-5+ hours on the bike at night, we suggest picking up a spare battery pack to keep nearby. You will be able to confidently ride with the light on a medium or low setting on pitch black roads which will give you significantly more runtime, however always good to have a backup battery on hand. The Road Edition was successfully used in the RAAM race in 2019 with great reviews.


Gravel Riding
Who doesn’t love long rides along a riverbank or a train tracks? We have gotten a lot of questions about the best light for gravel riding since it’s a mixture of off-road “trails”, but often sharing the trail with other bikers and pedestrians. Because of this we recommend the Road Edition for gravel riding. The Road Edition light was originally tested a lot on the Katy Trail that runs through St. Charles, MO and because of how pitch dark it gets on the Trail we could run on the lowest setting and still ride comfortably. Meaning you can go for days doing a few hour stints at night without worry of the battery draining.


Single-track
Now we get into the real off-road stuff. If you are riding twisty single-track trails then the Trail Edition was designed specifically for you. A wide evenly lit beam pattern lets you mount the Trail Edition on the handlebars and move the bike around without losing what you are looking at. This one is a pretty easy recommendation because the Trail Edition was designed around singletrack riding from the start.


Really Fast Single-track
If you attack your trails at night like you are trying to get KOM on Strava then the Ultimate Downhill Package is going to be up your alley. The wide illumination of the Trail Edition along with the tighter, punchier beam pattern of the Road Edition will create a wall of lighting that is unbroken when you are looking deep into corners or approaching switchbacks. The combination of the same color temperature, and the integrated light carpet is nothing short of amazing when both are turned on and you start riding hard.

We hear this all the time, but it is literally like riding in daylight.


Recumbent Riding

Much like road riding, the lights for a recumbent bike follow a similar guideline. If you are on the road then try using the Road Edition. We have had dozens of customers mount this on their recumbent bikes with great success and rave reviews.

As you can see, different riding requires different types of lighting. There is no one-size-fits-all solution (yet!) and in order to get the best light for your bike it’s best to be honest about where and how you ride. If you have any more questions you can always drop us a line by emailing us [email protected] or give us a ring. Always happy to chat lighting and recommend which lights will work best for you.

Friday, 29 June 2018 / Published in Updates

We’ll be the first to admit, this is somewhat of a marketing ploy. Why? Because a lot of people are absolutely fixated on the reported lumen number of a light.

Our lights use about 20% less than the “equivalent lumens”, so what are we trying to say? We are trying to say that our light performs like a higher powered light, but while using less lumens. How is this possible? Through the use of engineered beam patterns that accurately put each lumen exactly on target to get the most out of it. That means that we can have a wider beam with the same intensity because we are using the light more efficiently.

Through proper engineering design we can determine the peak hotspot intensity needed to feel comfortable at night, and then take that excess energy that normally would be focused with a high lumen spot light and spread it out to balance the brightness so that you are left with a light that allows you to feel more comfortable riding, as well as redirecting light that normally would be wasted through excess energy on the ground, or just going straight up into the tree-tops which is not where your eye is looking. There is a lot of research, math, reverse engineering, measuring, and some judgement to develop these beam patterns.

The peak intensity will not be as great as some higher powered lights, but the second your handlebars start moving and you start actually riding, you’ll get it, and you’ll love it.

Monday, 05 February 2018 / Published in Technology

It’s a pretty logical thought right? A light that is 2000 lumens will be twice as bright as it’s 1000 lumen brother, so I’ll be able to see twice as far. Seems fair. However once we look into the reality of the situation, come to realize that it isn’t true. In fact in order to see “twice as far” you’ll need a light that is FOUR times brighter, or a 4000 lumen light using the same optics. Why is that? Pretty simple really. Math.

If you haven’t already, I suggest that you read our earlier blog post on lumens, lux, and candella  HERE to get up to speed with the terminology.

It is a fairly commonly held perception that 3 to 5 lux is amount of light that the average person needs on an object in order to quickly and reliably spot it on either a trail or a roadway. This is a figure that is independent of distance. This covers everything from tree branches, to the trail, to road markings, other pedestrians, or parked cars even, simply just how much light is needed on a target.

So with that number in mind we can start to think about situations where we need that much light in order to light up something enough to recognize it quickly. Lets say you are riding with a 1000 lumen light (actual lumens!) and there was a big rock on the trail 50 meters in front of you, this means we need a light that can light up that rock with 3 lux of illumination at 50 meters. We can use some math to figure out how much candella, or light intensity is needed from our light:

Iv(cd) = Ev(lx) × (d(m))2

Iv(cd) = 3(lx) × (50(m))2

Iv(cd) = 7,500 cd

Now, we can think of candella and lumens as linearly related, i.e. lumens is like a volume knob for candella. Twice as many lumens will increase the candella of that point twice as much. Easy right? So now lets say you were riding with a 2000 lumen light, so your candella is now 15,000 cd, logic would dictate that you should be able to see that rock from 100 meters away now right? Well let’s look at the numbers:

Iv(cd) = Ev(lx) × (d(m))2

15,000(cd) = 3(lx) × (d(m))2

15,000(cd) / 3(lx) = (d(m))2

(15,000(cd) / 3(lx)) = d(m)

 d = 70.7 m

So instead of being able to see that rock from 100 meters out, you only gained a 41% improvement in actual spotting distance despite a 200% increase in the number of lumens in your light. This is part of why big lumen numbers are not key. What is more important is the quality of the beam pattern and how those candella intensities are spread out within your field of vision. These are not easy to report numbers, and have to rely more on wall shots and user reviews in order to figure out what is a quality beam pattern. If you see an ad for a light that doesn’t show exactly what kind of beam pattern you are getting, run away, proper companies that do the work for developing a proper light will be happy to show you wall shots showing off how smooth and well illuminated their patterns are. For example, here is the Trail Edition beam pattern, can see how radically different it is from the typical bike light found.

If you have any other questions, always feel free to start up a chat!

-Matt Conte

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