Originally Posted by
soloist_huaxin
Could you elaborate on the tread part? I thought slicker tread will slip more on gravel? I was thinking along the "knobbier/MTB-ish" side if there is such a thing on road tires...
The only time you need real knobs is in muddy conditions. For dry gravel, semi-slick is fine so long as it's wide enough for you to float on the surface instead of cutting through.
A semi-slick will roll much faster on pavement than a knobby. For example, compare the
Clement LAS to the Clement
PDX or
MXP. The file tread on the LAS is great for hard surface, whereas the others are more knobby for mud. Clements are excellent tires, btw.
You are light enough, so a 28 mm tire may be wide enough for occasional, small gravel (like a crushed limestone trail). If you can fit a 33 mm tire (I believe you can) then that opens up the wide selection of cyclocross tires, which should all be competent on gravel.
Personally, I'm much heavier (#225) and the gravel around here is quite rough (crushed lime rock, .5-1"), so I prefer at least a 38 mm tire to stay floating on top. My main gravel bike rocks with 60 mm Super Moto tires!