The Knog Blinder ARC 5.5 is the brightest in the new ARC range. At 550 lumens, this USB rechargeable light is powerful enough to be used by itself on the road, and can also serve as a secondary helmet light.
The ARC 5.5 is certainly bright enough for road use and commuting, but not for mountain bike trails – it seems underpowered compared to the current crop of trail-specific lights.
It has two interchangeable silicone mounting straps – 25-30mm and 30-35mm – so it's easy to attach this 152g light onto bars of nearly any size. Unfortunately, they're not that secure – throughout our rides, especially on rougher roads, the ARC 5.5 slowly tilted back until it was high enough to blind any passerby. Changing to the smaller strap did not remedy the problem on our oversized bars.
The quick-release strap makes fitting and removing the light simple and quick
Knog has included a strip of foam tape (not pictured) to stop the light from moving, which it does. However this solution is far from elegant, and is quite ugly on the bars.
We found burn time is in line with what is claimed – 1.8 hours on the brightest setting, 3.5 hours on medium, 7.9 hours on low and 17 hours flashing.
Knog’s constant current drive technology allows the light to maintain the same level of brightness up until the battery is depleted. We appreciated this feature when we noticed the low-battery indicator light up just a few kilometers from home. However it caught us by surprise a few times and left us without light, as we didn’t always see the low battery indicator.
With the combination of Knog’s unique elliptical reflector and a single CREE XM-L2 LED, the ARC 5.5 creates a beam wide enough for both commuting and after-dark training sessions. The reflector generates an egg shaped beam that illuminates hazards long before you reach them. Knog claims that the light's 16-degree (vertical) by 24-degree (horizontal) beam is visible at over 1,000m.
The cockpit can get a bit crowded when you use the ARC 5.5 with a Bar Fly mounted Garmin. The light sits right next to the computer, so the buttons on that side were difficult to access.
When used with a BarFly mounted Garmin, the ARC 5.5 creates a crowded cockpit
To our knowledge, Knog is the only light manufacturer that has integrated the USB charging plug into the light. However, the feedback for this is mixed, and a few users have reported that the charging plug does not reach a laptop sitting flat on a desk. Although the ARC series of lights does not suffer from this issue, Knog has included a small USB extender cord for charging.
The ARC 5.5 is completely waterproof and dustproof, so there's no need to worry if you get caught in a torrential downpour or accidently drop it in a bucket (don’t ask).
While we have our niggles about the light’s tendency to twist back on the bars, the Blinder ARC 5.5 is surprisingly powerful, compact and well constructed for its price.