Originally Posted by
mattscq
That is interesting—using GP5000s on gravel. I suppose before I knew any better, I got lost in a park once and ended up on some paths that seemed like nobody had travelled on or serviced in decades (so broken up it was basically loose gravel) and I managed to get by on 25mm GP4000s at probably 80-100 psi. It was crazy bumpy and not pleasant but I didn't flat and continued to ride many many miles after.
I do realize now that the knobby SK+ were probably designed for very loose gravel and mud which I don't really encounter that much. If I wanted a slightly better all-rounder, would the slicks serve me better?
Yeah, if you don't encounter a lot of loose gravel and mud, that is an option. Jan Heine (Bicycle quarterly, Rene Herse tires) wrote an interesting article on how slicks and treaded tires have basically the same traction in those conditions (for what that is worth).
I chose the 32mm GP5000 if I'm riding on gravel less than 2cm in size, when 40-45psi is enough, and when it is dry (pretty much everything this type of year). They are best for mixed road/gravel, because they roll very very nice on the road. If its muddy, sandy, rocky, rooty, or more of an edurance ride (where I want lower psi), something bigger is my choice. A lot of it is my bike, but I ride some pretty nasty washboarded stuff on these, and its shockingly smooth. But if you need a bigger slick, the slick GK, or Rene Herse have some good options.