http://surlybikes.com/bikes/long_hau...ame_highlights 2.1 on the 26
I just did an Ogre build and went with 40mm Mondials, they are quite meaty, but roll decently. A very heavy duty tire, just ask if you really need more because maybe for hardcore dirt I would but for road and trails, they are pretty heavy duty. I mostly wanted flat resistance and sturdy and they are more than enough for that.