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£89.99  151g

Knog Blinder Arc 640 front light is, according to their blurb “for serious road and trail riders”. We’d describe it as a versatile model for commuters and sub/urbanites, who want to inject a bit of serious rural fun into their rides home, but without the bulk of external batteries.  


Godzilla of the range, it only weighs 164g and at 100x32x32mm leaves ample room for blinkies, computers, GPS and similar training aids.  Knog’s quality control has improved year upon year and the Blinder Arc are cases in point.


Solid 6061 aluminium shells come in a choice of anodised colours and disperse heat very efficiently, which gives internals the best chance of leading, long and productive lives.  


Meeting IPX68 standard for weather proofing, silicone sections insulate the rechargeable li-on cell and USB plug in from everything bar full on submersion. Ours passed my five minute hosepipe torture test with flying colours and even survived an accidental swim without missing a beat.


The 640 boasts a single, super potent XM-L2 diode. The lens is made from an equally sophisticated acrylic called PMMA, which is very tough, yet easily moulded to project an incredibly crisp combination of spot and flood beams. 


A lack of side windows might put some off but as these shot, taken at 40ft in pitch darkness suggests, there’s no chance of you dropping off the radar - regardless of setting. Talking of which, there are four – high, medium, low and flash commanded by a recessed, top mounted switch. 


This is easier to operate wearing winter-weight full finger gloves than size suggests and becomes intuitive with practice. And since it needs a definite, sustained press, there’s no danger of it accidentally switching on in pockets or luggage. It also incorporates a charge and battery indicator, which is more of a slither as opposed to a window


This season’s mounting straps look identical but we’re assured they’ve been given a steroid injection to better accommodate oversized diameter handlebars. The kit also includes a helmet lamp, smaller strap for those between 25 and 30mm, with a beefy rubberised shim for perfect purchase on super skinny 22.5mm tubes. 


Either way, they’re easily replaced and covered under warrantee, so only time will tell. Ours still look and behave like new, despite being regularly swapped between bikes, or removed when locking up in the street. 


Talking of which, flashing is brilliant for being seen round town, or on overcast afternoons, capturing most people’s attentions at 300metres. On clear, starry nights, we’re talking nearer 700metres - impressive and more than adequate for most of us but not quite the 1,000 suggested. 


Surfing between modes is simply a matter of depressing the power button for a quarter of a second. Low produces roughly what I’d expect from a 250 lumen unit, with more than enough bite for scorching through the suburbs, slightly underpowered but passable in semi-rural contexts, say in the event you need to nudge down to conserve juice. Talking of which, from a full charge this has consistently returned 7hrs 3mins, which is potentially enough for a weeks’ middle distance commuting. 


Oncoming traffic picked us out at 400 metres plus, although weren’t inclined to dip their lights, whereas mid was much more persuasive, stopping short of dazzling but easily powerful enough for hustling along at 23mph plus with ample warning of holes, glass, mud and other potential hazards. 


Medium is probably the best blend of output and frugality, easily on par with some five hundred lumen models. Oncoming traffic dipped their lights at around the 150 metre mark and the light quality is good enough for navigating these unlit routes at 20/22mph, with ample warning of upcoming hazards. 


Unleashing the full 640 and we’re talking enough power for thirty mph plus - once again, the quality of light is superior to some budget models reckoned to produce 1,000lumens


Thankfully, those collimator lenses and high quality reflectors ensure the beam is channelled correctly - so no risk of dazzling yourself, or in most cases, other road-users. 

This setting is just powerful enough for sneaky bits of single track fun at 17/18mph on clearer nights and makes a decent companion for more aggressive trail antics when helmet mounted. 


Alas, 1hr 45 and the battery’s completely exhausted. Not that far behind some high power models using external, frame mounted li-on cells perhaps, but there’s very little leeway, say if you’ve been delayed by a puncture, or just lost track of time.

Knog Blinder Arc 640 Bicycle Front Light
Knog blinder Arc 640 bicycle light water proof hose pipe test

Michael Stenning


Verdict: 4 out of 5: Well-made and extremely versatile compact light with phenomenal output.


Pros: Phenomenal power in the highest mode.

Cons: slow charging when fully spent .





Ryton On Dunsmore

Coventry  CV8 3FH


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