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Knog Blinder Arc 1.7 front light



Stunning performance and reasonable run times but built-in USB plug can be awkward

The Knog Blinder Arc 1.7 front light packs phenomenal punch given its rated output is only 170 lumens. However, while aesthetically pleasing, its flip out charge stick wasn't universally compatible with laptops and other portable devices.

With their aluminium fascia, polycarbonate bodies and trademark silicone covers, the Arc series lights are seriously handsome beasts. Knog's build quality has also improved year on year and ours looks packet fresh after several weeks' use.

Weather resistance has always been a weaker spot on lights that recharge by plugging directly into a USB port, it's a surprise that the Blinder Arc 1.7 meets IPX68 standard. That means it's totally impervious to dust and waterproof in the fully submersible sense.

Suffice to say ours hasn't missed a beat during the heaviest cloudburst and passed my hosepipe test with flying colours. Even a dip in salty coastal waters couldn't faze it.

Internally we have a single Cree-XD LED amplified by high tech reflector and wide angle lens. This is made from PMMA, a shatter resistant thermoplastic with similar properties to glass but without polycarbonate's environmental impact.

A bean shaped switch nestles between a series of beam codes, reminiscent of those found in cars, and a tiny traffic-light charge indicator. Despite their size, all are surprisingly user friendly. The switch requires sustained two-second pressure before powering up, so accidental engagements are unusual.

The brightest mode is default, dropping to medium, low and flash with consecutive prods. Output and beam quality are jaw droppingly good, easily on par with some 400 lumen models along unlit backwaters.

Not unexpectedly, this uses the battery's charge alarmingly quickly. The red light came on some 35 minutes into an hour's loop but the light manages the claimed 1 hour 15 minutes run time almost to the second.

Knog's official figures claim visibility to 1,000 metres. Slight exaggeration by my reckoning, though on clear nights, friends in cars and oncoming club folk reckoned they could spot it from a good 750-800 metres.

That full beam mode is just the ticket for semi-rural service and medium or low are good for suburban contexts. Low mode snares driver attention from around 450 metres, dipping to a still commendable 300 through town and moderately lit shared use paths.

Flashing tends to be the setting that divides opinion, though the clever lens throws its funky tempo at just the right angles - no danger of falling off the radar when tackling roundabouts at dusk.

Charging requires the full four hours and shouldn't be an issue for disciplined types but could prove a little tricky in some offices. I had difficulty fitting the Blinder Arc 1.7 to some USB ports, a problem I overcame using an extension cord from a Blinder Road light. It'd be nice if that extension were included in the Blinder Arc bundle.


Stunning performance and reasonable run times but built-in USB plug can be awkward

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Make and model: Knog Blinder Arc 1.7 front light

Size tested: Blue

Tell us what the light is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

"Loaded with a 170 lumens of light the Blinder Arc 1.7 gives riders total visibility and freedom at night, all from a super-compact, super-light, USB rechargeable, 100% waterproof, integrated silicone package. Equipped with one of the latest high-intensity XB-D Cree® LEDs, keeping motorists and road users at bay the Arc 1.7 uses an elliptical beam of 16° vertical and 24° horizontal beam making the light visible to others at over 1000m". Surprisingly faithful to the blurb, though think 750-800m more accurate.

Tell us some more about the technical aspects of the light?

OUTPUT : 170 lumens

DIMENSIONS : 32 x 32 x 70.8mm.

WEIGHT: 100g

MATERIALS : UV-Resistant Industrial grade silicone. Polycarbonate housing and PMMA Lens. Hard-anodised aluminium fascia.

USB : Rechargeable Lithium Polymer battery

Rate the light for quality of construction:
Rate the light for design and ease of use. How simple was the light to use?
Rate the light for the design and usability of the clamping system/s

Intuitive design that fits all diametersbut a bit fiddly to operate in gloved hands. Some people suggested they'd had problems with the silicone strap stretching and thus sliding round. Ours seems extremely dependable so far despite being regularly ported across a wide variety of bar diameters.

Rate the light for waterproofing. How did it stand up to the elements?

IP68 is very reassuring. Giggled at my hosepipe torture test.

Rate the light for battery life. How long did it last? How long did it take to recharge?

Economy is impressive relative to output, returning 1hr 14 in high, 2hrs 35 medium, 5hrs 49 low and 11hrs 53 in flashing. However, 4 hour charge times are considerably longer than many and a USB extension cord would make this process more convenient.

Rate the light for performance:

Output is incredible, especially in the highest setting.

Rate the light for durability:

Build quality seems excellent and to date, genuinely impervious to the elements.

Rate the light for weight, if applicable:
Rate the light for comfort, if applicable:

Seems well insulated and hasn't become hot to touch. Beam is similarly well focused, so doesn't dazzle the rider like some can.

Rate the light for value:

Tell us how the light performed overall when used for its designed purpose

Overall, the Knog blinder Arc 1.7 is an extremely versatile light best suited to sub/urban contexts. However, its bigger brother looks a better choice for those regularly riding beyond city limits.

Tell us what you particularly liked about the light

Pretty much everything given the design brief.

Tell us what you particularly disliked about the light

Not completely sold on the flip-out charge port concept. This works very well on bobby dodgers but I'd like to see a connecting cable included for convenience.

Did you enjoy using the light? Yes.

Would you consider buying the light? Would probably plump for its bigger brother given my present locale.

Would you recommend the light to a friend? Yes but with certain provisos.

Overall rating: 7/10

About the tester

Age: 40  Height: 1m 81  Weight: 70 kilos

I usually ride: Rough Stuff Tourer Based around 4130 Univega mtb Frameset  My best bike is: 1955 Holdsworth Road Path and several others including cross & traditional road

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Experienced

I regularly do the following types of riding: cyclo cross, commuting, touring, fixed/singlespeed, mtb,


Shaun Audane is a freelance writer/product tester with over twenty-eight years riding experience, the last twelve (120,000 miles) spent putting bikes and kit through their paces for a variety of publications. Previous generations of his family worked at manufacturing's sharp end, thus Shaun can weld, has a sound understanding of frame building practice and a preference for steel or titanium framesets.
Citing Richard Ballantine and an Au pair as his earliest cycling influences, he is presently writing a cycling book with particular focus upon women, families and disabled audiences (Having been a registered care manager and coached children at Herne Hill Velodrome in earlier careers)

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