Koo’s fabled lens clarity and rugged construction makes these Demos glasses an ideal choice for mountain bikers, discovers cycling expert Matt Ray.

Matt’s been testing cycling kit for years and know how to put gear through its paces. He donned these Demos for a variety of rides on asphalt, dirt and gravel and in a wide range of temperatures and lighting conditions. Overall, their lens clarity earned them a place in our best cycling glasses buyers’ guide.

Koo Demos Glasses (w/ Orange Mirror Lens)


From $150 / £150, koo.com


  • Excellent lens clarity
  • Optimal ventilation
  • Many colour and lens options


  • Tight arm grips

Clarity: 5/5
Cycling Design: 5/5
Comfort: 3/5

The ‘90s vibe of the Koo Demos ice blue frames and mirror orange lenses inspired me to take my MTB out onto the pure-white chalk ribbons of the South Downs for some good old-fashioned trail riding. The outstanding lens clarity and cycling-specific design delivered distinctly modern results…

Koo Demos features

Koo may fly under the radar as a brand in the UK, but I already knew that the clarity of its Zeiss lenses was incredible, having used Koo ski goggles in the past. After blasting along the endless chalk trails of the South Downs in the Demos, I can say that the lens clarity really is up there with the Oakley Kato Cavendish Edition, but they cost over £100 less.

The orange mirror lenses of this model let in 35% of the light. Transitioning from riding from open downs to forested trails could have been a high-contrast challenge. Thankfully, the Demos rose to the occasion, making them a great choice for mountain biking. I often have to take my shades off when riding in the forest, but the mirrored-finish Demos could cope equally well in bright sunshine and in the trees.

The Demos have the same anti-slip Megol elastomer temple grips at the Rapha Pro Team Frameless, so it was surprising that the arms felt so tight. I appreciated the extra grip on rocky descents, but in terms of long-distance comfort it’s a bit excessive.

Koo Demos performance

Dropping off a fast, sun-drenched trail into the gloom of a wooded escarpment can be a testing experience as your eyes adjust, but stopping to remove or adjust your eyewear really kills the flow. Fortunately, the Koo Demos allowed me to ride on uninterrupted, while the well-designed ventilation slits kept the sweat out of my eyes.

The transparent frame looks the business and the sunglasses are tougher overall than frameless designs. I trash way more sunglasses on the trails than on the roads, but the Koo Demos were well suited to the rigours of mountain biking.

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