So I was thinking of changing out one of both of the tires on my Kona Smoke. I am currently running 700 x 47 Continental City Contact tires (smooth with some lines running across). I mostly ride pavement but I have also been playing around on trails that are hard-packed dirt with a lot of loose gravel patches. Right now my riding is about 75% road, 25% gravel/dirt. The tires slip around a lot on the gravel, so I was thinking of going to something with more tread. My LBS suggested either a Schwalbe Land Cruiser 29 x 1.75 or a Kenda Karma 29 x 1.9. I was originally going to switch both tires, but after some reading I'm wondering if I shouldn't just replace the front? What are your opinions on that? I don't mind slowing down on pavement as a result of the added tread, but I really need a bit more traction on the gravel bits.
The terrain itself is pretty flat.