When choosing a bike light, lumen output gets all the attention. But here’s what lots of riders don’t realise: where that light actually goes matters more than how bright it is. A poorly designed beam pattern can leave you squinting at a bright hotspot while missing trail features in the shadows. A well-engineered beam puts light exactly where you need it.
The Gloworm CX Core Light System was designed as a versatile self-contained light that performs brilliantly both on helmet and handlebars, thanks to our interchangeable optic system. Let’s get technical about how it works and why we made the design choices we did.
The Engineering Challenge: One Light, Two Mounting Positions
Helmet-mounted lights typically work best with a narrow, concentrated beam for maximum throw, while bar-mounted lights need a wider beam to give you good peripheral vision. Most bike lights force you to compromise—choosing one beam pattern that’s acceptable for both positions but optimal for neither.
We took a different approach with the CX Core. Instead of making riders compromise, we utilised our unique interchangeable optic system that lets you optimise the beam pattern for how you’re actually riding.
It took days of optics design, many iterations and samples to reach a result we are proud of. We’ve achieved around 94% optical efficiency, which we’re quite proud of. In practical terms, this means more light reaches the trail instead of being lost inside the optics. When you’re pushing through technical sections at speed, that efficiency translates directly to better visibility
The LED Array: Four LEDs, Two Types
The CX Core uses four carefully selected LEDs in a specific configuration. After extensive testing, we chose two XP-G4 LEDs in the centre for better throw and two XP-L2 LEDs on the sides for a slightly wider beam and higher efficiency.
Here’s where it gets interesting: we’re using two LED drivers that can be independently controlled to accommodate the two different LED types. This dual-driver architecture allows us to maximise the output from each LED while maintaining precise control over the beam pattern.
Standard Optic: The All-Rounder for Helmet Use
The standard optic that comes installed in every CX Core is optimised for helmet mounting, though it works well on handlebars too.
Beam Characteristics
What you’ll notice first is a defined central hotspot that lets you direct light exactly where you look, simply by moving your head. The beam is slightly oval horizontally, giving extra peripheral vision without glare. This balance makes it a brilliant all-rounder, especially for helmet use.
The beam pattern shows impressive throw distance while maintaining enough width for trail awareness. At 75% intensity, you can see the concentrated central beam surrounded by a controlled spill that lights up the sides without washing out your vision.
Best For:
- Helmet mounting for trail riding
- Mixed terrain where you need both throw and peripheral vision
- Riders who want one versatile optic for most conditions
- Technical riding where you’re constantly looking ahead and to the sides
Wide Optic: Maximum Peripheral Vision for Bar Mounting
The wide optic (available with the CX Core Bar Mount Upgrade or individually(coming soon)) produces a broader, more elliptical beam, ideal for handlebar mounting. The shape spreads light further to the sides, giving a wide, even field of view but with slightly less throw than the standard optic.
Beam Characteristics
Where the standard optic gives you a defined central hotspot, the wide optic creates a broader flood pattern. The beam visualization shows how the light spreads more uniformly across a wider area, perfect for when the light is mounted in a fixed position on your handlebars.
This isn’t about being “better”, it’s about being optimised for a different job. When your light is fixed to your bars, you need that peripheral coverage because you can’t aim the light by turning your head.
Best For:
- Handlebar mounting as your primary light
- Open terrain where you need wide coverage
- High-speed riding where peripheral awareness is critical
- Riders who prefer bar-mounted lights over helmet lights
The Ultimate Setup: Two CX Cores with Different Optics
Using two CX Cores, one with the standard optic on your helmet and one with the wide optic on your bars, creates what we believe is the best combo for serious night riding.
Here’s why this combination works so well:
Helmet light with standard optic: Provides throw distance and lets you look into corners, up climbs, and at trail features by simply turning your head. The defined hotspot follows your vision.
Bar light with wide optic: Floods your peripheral vision with even light, showing you what’s coming in the wider trail context. This fixed light creates spatial awareness while your helmet light handles the details.
That’s why we created the CX Core Light System Bundle. The combination gives you the best of both worlds—the precision of helmet-mounted lighting with the spatial awareness of bar-mounted illumination.
The Ultra-Narrow Optic: For Maximum Throw
We also have an ultra-narrow optic in testing for riders who prefer a tighter, more concentrated beam on the helmet. This optic maximises throw distance for riders who want to see further down the trail or who ride very fast on open terrain.
If you’re interested in an ultra-narrow optic option, let us know. We’re gathering feedback from riders to determine if we should make it available.
Beam Patterns vs. Lumen Claims: What Actually Matters
When comparing mountain bike lights, pay attention to beam pattern engineering, not just lumen numbers. A 2,000 lumen light with a poorly designed beam pattern will perform worse than a well-engineered 1750 lumen light like the CX Core.
Here’s what to look for in quality bike lights:
Central hotspot definition: Can you direct light where you look, or is it just a vague flood?
Peripheral coverage: Does the spill light provide useful vision, or is it wasted light creating glare?
Optical efficiency: How much of the LED output actually reaches the trail? Quality helmet lights and rechargeable bike lights should aim for 90%+ efficiency.
Mounting versatility: Can you optimise the beam for different mounting positions, or are you stuck with one compromise pattern?
Mounting Flexibility: GoPro-Style Quick Release
Every CX Core comes with a GoPro-style adapter, so you can mount it neatly under your bike computer or cycle computer if that’s your setup. For bar mounting, the CX Core Bar Mount upgrade includes both the wide beam optic and a quick-release mount specifically designed for handlebar use.The quick-release mount makes it easy to switch the light between bikes or remove it for charging.
For helmet mounting, the CX Core includes a low-profile helmet mount adapter as standard, designed to minimise profile while maintaining secure attachment during technical trail riding.
Why Beam Pattern Engineering Matters
The difference between adequate lighting and confidence-inspiring illumination comes down to beam pattern engineering. We spent countless hours testing LED configurations, optic designs, and beam shapes to get the CX Core right.
The interchangeable optic system means you’re not locked into one beam pattern. As your riding style changes, as you switch between helmet and bar mounting, or as you tackle different terrain, you can adapt your light to match.
Whether you’re commuting with cycle lights, tackling technical singletrack with mountain bike lights, or pushing your limits on long night rides with rechargeable bicycle lights, understanding beam patterns helps you choose the right lighting setup for your riding.
The Bottom Line
Lumens tell you how much light the LED produces. Beam patterns tell you where that light actually goes. The CX Core’s interchangeable optic system gives you control over both.
For most riders, the standard optic provides excellent versatility for helmet or bar mounting. For riders who want optimised performance in both positions, running two CX Cores with different optics delivers the ultimate night riding setup. And for those who need maximum throw, we’re testing an ultra-narrow option.
In the world of mountain bike lighting, performance isn’t defined by lumens alone. It’s shaped by optical design, beam pattern, and purpose of use.
Ready to experience precision beam patterns? Explore the CX Core Light System and Accessories.