This is the classic New Mexican sampler platter of Los Alamos riding: rocky technical wagon trail, smooth skinny singletrack and steep creek diving. This counter clockwise loop is best linked up with the fitness trail from town or the southern extention of the Perimeter trail, or both. By itself it's only an hour, maybe. Link it with the other two trails from town and its a decent 2.5 hr ride that is almost 100% singletrack.
The Nail Trail starts in a dirt parking area on the right side of 501 (coming from town) first right after the ski hill turnoff. Park here and ice the
beers. Start off by riding down the short slope from the parking area and immediately cross the creek bed (usually a little water in spring and early summer). The technical shit starts off right away (see left) as you climb out of the creek bed and eventually on to an old wagon trail which is a grunt for about a 1/4 mile or so. The trail gets smoother and less steep the higher you climb. The climb is about 2-3 miles, mostly pretty gradual. There may be a few forks in the trail (most of them are pretty overgrown these days) - but if in doubt, stay left. The trail pops out onto a south-facing slope that was burned in the Cerro Grande fire and there may be a few snags that 
have fallen across the trail - usually no big deal. As you are crossing this slope you will hit the high point of the ride- then, with Pajarito Canyon on your left you will start to drop into this narrow-assed canyon. The trail is fast and twisty with lots of shit to run into (see bottom right). The trail crosses the creek a few times through some really steep drops and eventaully ends up in the slimey Berth Kanal - if you see it you'll know why its called this. This part of the canyon is narrow and dark and is also a popular place for climbing. The Berth Kanal spits you out on a short sweet section of singletrack that eventually heads back to the parking area or connects with the perimeter trail.Check out the Nail Trail and the Berth Kanal...you'll be "born
again". 
Post Ride Beer: Kirin Ichiban
