Koo Demos are an excellent pair of mountain bike and gravel glasses and, with this lens specifically, they are brilliant in downright grey and horrible conditions. They are very comfortable and lightweight and grip well without pressing or rattling on various helmets. They are prescription clip-in compatible and a large selection of aftermarket lenses are available making this one of the best mountain bike sunglasses at the moment
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Koo Demos are a supremely comfortable pair of mountain biking glasses with sticky flexible arms and adjustable nose plates. The lens quality is excellent as is the coverage. With this Rose lens, they are perfectly suited to cloudy rainy days and there are 16 standard combinations to choose from. If you require a prescription lens then the Demos fit a standard optical clipin lens holder.
Koo Demos sunglasses -Technical details
Demos come in a multitude of colour combinations but here they have a gloss-black frame with simple Koo branding written on the arms and a polycarbonate rose lens with Koo branding above the nose. The frame sits both in front of the lens and behind it making it look like these are three-quarter frames at some angles – it's a neat trick and very smart. The frame and lens design offers four ventilation ports, two at the brow and two on either side of the nose clip for fresh air to circulate and hot air to escape to prevent fogging.
The lens is made from polycarbonate and designed in conjunction with the huge optical mega brand Zeiss, a company synonymous with high-quality optics and one that you will see banded around on the best cameras, phone lenses, and multiple sunglasses.
The lens is interchangeable with a wide selection of other UV filters so once you have chosen the initial pair, you can then purchase other lens kits for different conditions if you want
The rose lens offers a filter category of 1 (Category 0 - 4, where 0 is the lightest and 4 is the darkest filter) and a VLT (visible light transmission) of 58% ideally suited to low light and cloudy conditions delivering high contrast levels.
The attached nose clip (there are two clips supplied) has adjustable angled nose pads for increased comfort and the arms are super flexible with long soft MEGOL elastomer inserts for grip.
Demos are supplied in a bag for safekeeping and cleaning duties. In this case, it's a white bag so you will be able to see when it needs washing. They cost £140 weigh in at 33g and come in 16 different coloured versions which you can later customise.
Koo Demos sunglasses - Performance
These are a great pair of mountain biking sunglasses which can, of course, be used on your gravel bike and road bike as well, just don’t go shopping in them. Firstly they are very comfortable on my face and this is subjective but I’d say they are the most comfortable frame that I have tried in a long time. There is no pinching on the temples from the MEGOL tipped arms, you can feel them but they are not overly tight like the Melon Alleycats are when you first put them on. The ends of the arms are very flexible and this allows them to contour fit differing head shapes for maximum grip and comfort.
The nose piece has adjustable pads which, on my nose, both felt fine but allowed the lens to be moved closer to my face when they were pushed wide open. If you need a prescription clip-in frame then you will be unable to run them quite as close to your face as with the nose piece tabs fully flattened but still plenty close enough for crud protection.
The frame on this pair is gloss black but I think I counted 10 standard colour options of frames (plus limited editions) and nine different lens filters so there is almost too much choice. Luckily Koo offers 16 standard options so you can start with one of these and then buy another lens if you need a different level of filtering for winter riding as opposed to bright sunshine riding. Or vice versa.
The polycarbonate rose lens fitted is excellent in cloudy, poor and low-light conditions. It has a gentle pink hue to the landscape but not enough to be offputting. Gloomy days are much brighter and foliage sharper and only when you take them off, do you notice the overcast conditions.
Demos feature a Zeiss Anti-Reflective coating on both sides of the lens and I think it is perhaps the best implementation of this technology I have used so far with no discernable issues on the inside side lower edge which can be distracting
The downside of this rose lens unfortunately is that should the clouds clear off and the sun come out then the lens is too bright, but that is not the lens’s fault. This would happen with any other fixed high-visibility VLT lenses. One way to make sure you always have the right lens for the conditions would be to choose a pair with a Photochromic lens with an adaptive filter range of 1 to 3 and VLT of 12,5 –69%. That way you get the best of all scenarios but they do cost more – £180.
If you want to buy the Photochromic lens for your existing Demos sunglasses then the lens alone costs £80, which is a large chunk of cash. Normal lenses start from £35 so you could always pack a spare fixed lens for brighter conditions with you on a ride to pair with these rose Demos as it's very easy to swap them out.
On the bike, the Demos gel well with all my helmets from trail and cross-country to road/gravel. There is very little movement of the frame against the brow of the helmet and no unwanted chatter. The arms don’t clash with the straps or the sides of the helmet which further increases the fit and comfort.
Eye protection is spot on with a really good close fit to my cheeks preventing filth from getting up inside. I can see the black frame at the bottom of the lens only if I look for it but otherwise, it is not blocking any of the useable visible range. The frame is more visible when looking sharp left or right at the outer edges of my vision but only just. I’ve not noticed it on a ride and it might be completely removed by adjusting the nose pads and the closeness of the lens to your face.
Koo Demos sunglasses - Verdict
At £140, the Demos represent a decent chunk of cash for a set of sunglasses but they are well-built and provide an excellent clear viewing experience.
For the same money, you can buy a pair of Melon Optics Alleycat Photochromic which are extremely good although not quite as comfortable as the Demos or as good-looking in my opinion. But you do get that photochromic lens at that price which is a bonus.
For a little less you can get £112 Sweet Protection’s Memento RIG Reflect glasses but the lens is not changeable. For a lot less you could try the Alpina Bonfire Q-Lite Glasses (tested at £50) for only around £65, but you will need to buy a clear lens for winter riding for £35.
At the top end, there are excellent models from Oakley with the £240 Katos and the £230 Poc Devour models but you are spending another £100 on top of the Demos and both are bolder designs that might not appeal to some or work with your helmet.
The Koo Demos are an excellent pair of riding glasses that not only protect your face from everything being flung at it but are also extremely well-vented with zero fogging during repetitive hot laps on a warm, damp day. It doesn’t hurt that they also look great, can take different lenses and can easily fit an optical clip-in for those who require one. The best thing is you don’t notice them at all and that’s all that can be asked of a pair of riding glasses. Excellent.
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