Hello, first post in this forum. I've got an old Diamond Back Response Sport, 1993, that is needing new tires. The size is 26 x 2.1. I ride it off road on trails I've made and need some recommendations for good quality knobby type tires. There are slick roots and sharp imbedded rocks to contend with. The tires on it are what came on it new. Can't believe they still hold air! But the terrain I ride in has shredded most of the knobs off and even have some cord showing in spots from the rubber being ripped off. Thought I'd get on here to get some suggestions for which tires would work best for me. I'll be 69 in a few weeks and started back racing motorcycle hare scrambles after a 36 year layoff. Trying to get in the best shape possible and biking has become part of my work out routine. Any suggestions would be appreciated!