OK, I'll fess up that I tried the IRCs that I found before; 4.00 x 18 rear, 3.50 x 18 front. I had fun on a bunch of gravel roads, not doing anything silly because I don't know how but I had good control. When I got home from my first ride on them, parked right outside my gate, I glanced up my skid road up the hill and said, "Why not?" Indeed they were flawless on the hard packed slick clay stuff, though I think the R65 is pretty heavy for that stuff. (But the big dual sports are even heavier!)
But. I rode to work on them, cautiously in the morning, with no real problems. But on the way home it was nice, dry, and clear, so I decided to see if they can corner. I hit a right hander with good visibility and nobody around and went through it like I normally do, and that front tire felt like it was walking out from under me, and I crossed into the other lane before I got it under control. It didn't feel like a skid, which would have just slapped my right down on the ground, but it scared the crap out of me. I still like those tires on dirt, especially, and would love to have spare wheels to put them on so I can poke around on the logging roads up in the coast range, but I dislike having to ride so cautiously on pavement that it's no fun. The tires were advertised as 80% road 20% dirt, but I suggest you reverse those numbers if you want to try them. And I would have to remove my front fender, really, as there is very little clearance in places. I'll try to attach a pic here of them:
