How to Choose the Best Bike Lights for Maximum Visibility

Buyer's Guide to the Best Bike Locks

You'd probably agree with me that the NUMBER 1 question that comes to find when buying a bike light is:

How many lumens do I need for a bike light?

It depends on the type of riding you do.

While the number of lumens is a very important consideration, it's only one of the many things you should consider when buying a bike light. There are other key considerations such as number of light modes, battery capacity, mounting types and your local bike laws. 

And that's why I've decided to come up with this detailed bike lights buying guides for cyclists like you.

Which lights are good?

Key Consideration 1

1. Types of Cycling You Do

I've seen many people make this mistake during their buying process.

They go for the one with the highest lumens they can afford. While this might be the safer option to go with, it's not always the right option and by knowing how lumens work, you might even save some money.

TAKE AWAY #1 - You don't need a bike light the HIGHEST lumens count.

Let me tell you why.

A higher lumens count doesn't necessarily means a brighter bike light.

99% of bike light manufacturers today specify the brightness in terms of Lumens, except maybe for a German company, Busch & Muller.

While there is nothing wrong with using Lumens, there is another way to do it, which is better but less talked about.

Let me introduce you to the term Lux.

Lux vs Lumens

What's a Lux and why is it better interpretation of the brightness?

Imagine the car salesperson telling you that the gas tank of the car you're buying is 20 gallons.

Would you know how far 20 gallons will last you? It depends on several factors, like the engine capacity right?

Lux is the Measure of the Light's Intensity and It Affects What You See

  • Lumens: The unit used to represent the amount of light (aka brightness) emitted by a single source.
  • Lux: The unit used to measure the amount of light in a specific area, a certain distance from the source. In other words, it's a measure of the light's intensity.
  • Beam Angle: The coverage of the light beam in front of you. A higher beam angle results in a diffused beam (lower lux), while a lower beam angle results in a focused beam (higher lux). A beam angle of around 20-30 degrees is what you should be looking for.
Lumens vs Lux

TAKE AWAY #2 - Get a bike light that suits your most common riding conditions.

How Bright Should the Lights Be?

For headlights, here's what I would generally recommend:

  • Unlit Roads: Aim for at least 700 lumens. The faster your speed is, the higher lumens you'll need. I'll explain why in the later sections.
  • Lit Roads: Minimum 500 lumens. Your light will complement the existing road lights, so you can still get away with a slightly lower lumens.
  • Off Roads: At least 1200 lumens with a focused beam. I'll explain what this means in the next section.
  • Day Time: Most lights are adequate for daytime riding as their sole purpose is for you to be seen. Look for a light with an eye catching Flash/Strobe pulse to attract attention.

For rear lights, here's what I would recommend:

  • Lit and Unlit Roads: Aim for at least 50 lumens with flash or strobe mode.

Key Consideration 2

2. Effective Visibility Range

Like I mentioned in the section above, most light manufacturers specify the brightness in lumens. 

Take 2 different set of lights with the same amount of lumens and their visibility range could differ.

It all depends on whether the light beams are narrow or wide.

A general rule of thumb:

For a headlight where you can clearly see 40-50 feet in front, the lumens count usually falls somewhere between 300 to 500 lumens. I wouldn't suggest going for anything below 500 lumens. 

How Fast Do You Normally Ride?

Let's assume for a second that you ride at 15mph and using a light with 50 feet of clear visibility.

With that, you'll have around 2.27s of reaction time. That's just about enough time for you to react to any hazards in front.

TAKE AWAY #3 - A good bike headlight should give you at least 2-3 seconds of reaction time.

If you ride faster at 20 mph with the same light, your reaction time reduces dramatically to 1.7s. That's just slightly longer than a blink of an eye.

Scroll through the tabs below to see how the difference in lux affects your visibility.

  • 10
  • 30
  • 50
  • 60
  • 70
  • 80
  • 100

Key Consideration 3

3. Types of Light Bulbs Used

Did you notice that most bike lights in the market today use LED (Light Emitting Diodes)?

Well, there's a reason for that.

TAKE AWAY #4 - Go for LED's as they're small, energy efficient and last forever (almost).

  • Energy Efficient: High quality LED's are 80-90% more energy efficient than traditional light bulbs which means that you'll have longer battery life on your bike lights.
  • Less Heat: Up to 95% of the energy in LED's are converted to light and only around 5% is wasted as heat. Compared to traditional bulbs, which does the exact opposite - 95% into heat and 5% into light!
  • Longer Durability: LED's generally don't 'burn out' or simply fail. Overtime, they experience what industry experts call lumens depreciation, whereby its brightness gradually decreases.
  • Light Direction: LED's emit lights in a specific direction. This property of LED enables bike light manufacturers to accurately control the light beams to shine to where matters most.

Now I don't see any reason why you should even consider non-LED bike lights!

Key Consideration 4

4. Number of Light Modes

Most bike headlights these days comes with at least 4 modes; the standard High, Medium, Low and Flash mode.

Some goes as high as 10+ like the Knog Blinder Arc 400.

From my experience, it doesn't matter how many modes are there. It's just a numbers game for the manufacturers to look better than their competitors.

What's more important is how you use the the light modes.

TAKE AWAY #5 -  You don't need a bike light with the most number of light modes.

However, it's important that you buy headlights with Flash/Strobe mode.

Most headlights today have them. But for some strange reasons, there are still lights without them.

Key Consideration 5

5. Battery Capacity

You can still find bike lights using disposable alkaline batteries today in the market.

For a longer battery life and durability, I'd you go with rechargeable batteries. Most bike lights either use the Lithium Ion (Li-Ion) or Lithium Polymer (Li-Pro) batteries today as they are lighter, smaller and has much more capacity. 

There were major advancement made in lithium batteries in the past 5 years so it's just not worth the effort to keep replacing batteries, especially if you use the bike lights on a daily basis.

Lithium Based Batteries are Preferred

Source: Wikipedia

The chart above shows why Lithium based batteries are preferred, especially for small electronic devices.

  • For the same weight, Lithium based batteries hold more charge.
  • For the same volu​me, Lithium based batteries hold more charge.

Size, battery capacity and battery life are relatively proportional. A longer battery life would require a larger battery capacity and hence a larger size.

That's the reason why lights with above 1000 lumens comes with a separate battery pack. Another reason is to avoid the battery overheating the entire light body.

So what's considered a good battery life?

TAKE AWAY #6 -  A good battery should last you at least 1.5 hours on High mode and up to 10 hours on Flash mode.

Some lights like the Cygolite Expilion 850 takes things up a notch with a user replaceable battery. With this, you can have the option of carrying a spare battery if you forgot to charge.

Key Consideration 6

6. Mounting Options

With most bicycle lights today, the 2 most popular mounting options are using straps mounts and clamp mounts.

When it comes to mounting locations, there are various options available, depending on the design of the light.

Top of the Handlebars

Knog PWR Rider Bike Headlights

Most bicycle lights are still designed to be mounted on top of the handlebars as its the most straightforward way.

  • Easy access to the buttons to adjust the tilt and tighten the straps
  • Crammed cockpit, especially on narrower handlebars below 40 cm wide

Below the GPS Unit

Light and Motion Urbans GPS Mount

Some newer lights like the Light & Motion Urban 900 are designed to be mounted on both on the handlebars and below your GPS mount with a separate mounting kit. 

It certainly looks better with this but it does come with a downside; it's harder to access the light and buttons while riding.

  • Very clean cockpit look as the light is out of your sight
  • Lights not easily accessible while you're riding

Front of the Handlebars

Knog Blinder Road 400 Headlights

Knog came up with a creative way of mounting the light which gives you the best of both worlds.

  • Clean cockpit look
  • Handlebars might be a little crammed if you're using a narrow one below 40cm

Key Consideration 7

7. Local State Bike Laws

In case that you're unaware, there are local bike laws in every state in the U.S. that regulates how bicycle lights are used.

There are also similar laws in the U.K. and Germany.

While each state might have a subtle difference between them, it's generally accepted that you should have both active and passive lighting on your bike.

Active lighting refers to the usage of bike lights, both a headlight and tail light.

Passive lighting refers to the presence of reflectors mounted on the bike.

Alternatively, you can also check your local bike club's website for the specific bicycle law in your respective states.

The good thing is most bike lights from reputable brands these days usually comply with the law. 

TAKE AWAY #7 -  Use a white headlight.

I know this might sound silly as most lights today are white.

But, occasionally I do see some older models which still use the traditional yellow bulb. Some even use their red rear light at the front!

You want to use a white headlight because these are usually made of LED's and are much brighter and lasts longer.

TAKE AWAY #8 -  Use a red rear light and put it on Flashing mode.

It's almost a given that rear lights all come in red today.

However, there are some cyclists who uses their headlights as the rear lights (for some reasons). While this might make you visible to the drivers, you're actually going against the law.

Now it's your turn

So that's all the things I would take into consideration when I'm buying a bicycle light.

Now it's your turn to go through the same buying process:

Which bicycle light best suits your riding needs?

The decision will ultimately be yours.

But if you need some help, I've reviewed some of the best headlights and best tail lights available in the market today.

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