Unfortunately, I meet a lot of folks out there w/o a clue as well. A friend of mine and I were recently hiking in Devil's Canyon (San Gabriel Wilderness) which is a pretty tough hike, and it's an "upside down" hike, meaning that you descend first (into deep Devil's Canyon), and then have to climb on the way out after you're tired. Anyway, we found two perfectly good mountain bikes sitting alone way out in the middle of no where. We had come down canyon and had gone down as far as a large water fall that blocks further progress downstream -- unless you're prepared for class 5 climbing. We knew we were alone. Thinking this to be odd, I called a friend of mine who is on a SAR team. He said that two mountain bikers were missing in the area.

The good news is that SAR picked up the two guys, and they were OK. Apparently, they had become overwhelmed with the grueling nature of the route. Lower Devil's Canyon is brush choked, boulder (large) strewn wash that necessitates a lot of climbing and bush whacking. (why anyone would carry a bike down that is beyond me) They abandoned their bikes, but on their return trip, they missed the point where the trail climbs out of the canyon (easy to do in heavy brush) and went deeper into the wilderness. Oh, and yes they were just wearing T shirts and bike shorts (the lows were down in the high 30's/low 40's but the days were in the high 70's). There are too many people who read the various "pasttime" magazines which pump up a particular sport but rarely if ever discuss the truly serious nature of accidents, getting lost, etc. in the wild. It's all really upbeat pablum.