Kenda's Flintridge Pro is a reasonably priced tubeless tyre that stands up well to harsh conditions.
Kenda recommends the Flintridge Pro for 'dry, hard and sandy' conditions, but they work pretty well in 'wet, rocky and rooty' as well. You wouldn't plan a paved-road ride around them, but they'll see you right for a few tarmac miles between home and gravel. The centre tread is almost constant, to afford smooth, low-resistance rolling over hard surfaces, while the more open pattern towards the sides affords grip in the slippery stuff – to a point.
After an easy tubeless setup on some vintage Mavic Open Pro rims (19mm internal width), they measured up at 36mm – so no stinting on volume there. On dry, firm surfaces they do perform very well. My measure of a tyre is whether I'm notably scared when things get dicey, having to change lines or brake unexpectedly, where your bike's position relative to the trail and yourself isn't optimal for force transfer down through the wheel/tyre interface to the dirt or grass below. No such fears with the Flintridge Pro – when a tyre is egging you on to push harder and brake later without fear of it letting go, that's a good thing.
What's surprising about the Flintridge Pro tyres is how well they work when pointed at the Scottish hills (or other geographies involving slick rocks, roots and the like). Set up 55psi rear, 45psi front for my 75kg frame, the Flintridge Pros didn't hold me back. Rolling over pothole-strewn gravel tracks, into overgrown swooping singletrack, across grassed riverbanks, and descending 5-10% grade trails where water run-off is such an issue there's a waterbar every twenty yards – no problem.
What was genuinely unexpected was how well they performed on short, punchy climbs of over 10%, where you're out of the saddle in the lowest gear. My vintage cyclo-cross bike is relatively highly geared, with a 38 front small ring and a 28 sprocket at the back – this isn't a ride that lets you spin out climbs. So there was considerable low-speed, high-torque, out-of-the-saddle effort required to clear short pitches. The Flintridge Pros did an admirable job, staying stuck to the wet, rocky, rooty trail surface, only letting go once all hope of forward momentum was pretty much spent anyway.
Towards the end of the ride, on a long tarmac drive, with tired legs, the centre tread kept things buzzing along nicely, ready for the next lactic-burnout transition back onto the last stretch of farm track.
No, these aren't the tyre you want for a winter cyclo-cross race in soft mud, but for most people, the balance of smooth centre tread with more open outer lugs on a pretty supple, easy-rolling carcass will work well.