You can wear it for cycling on road but not recommended for cycling in mountain. " Black, gray, and/or smoke lenses are best for bright conditions â€“ they dim the bright sunlight to ease the strain on your eyes. While the lenses do darken your vision, gray does not alter color, so everything remains the same color. Gray also makes a great lens color for driving sunglasses. Best for: road rides, especially on sunny days. Not for: mountain biking. The dark lens may be too dark for trail use, especially if you are dealing with shady areas and shadows. Gray wonâ€™t improve contrast, clarity, or depth perception, either, and those things come in handy on singletrack. " Sources: http://coachlevi.com/cycling/sunglass-lens-color-selection-guide/
Sure. Grey tinted glasses are best for bright conditions. Because they can dim the bright sunlight and reduce the glare. If you get grey tinted glasses for cycling, they can ease your eye strain. In addition, gray tint glasses won't change the color, so everything remains the same color. If you want glasses for road cycling in the sunny condition, grey tinted glasses are good for cycling. But they are not good for mountain biking, because wonâ€™t improve contrast, clarity, or depth perception.