(UPDATE 2015: As the Preserve has become more popular with hikers, the trail surfaces have been churned to sandpit consistency. The upper trail sections are less affected, but getting there can be an ordeal. This area may be most appealing after precipitation, with a fat bike, or simply viewed from a long way away. If you don't like sand, run away.)
The best entry point for the El Cerro de Los Lunas Preserve is the parking area on NM6 (see marker). From here follow the signs. You'll ride about 1 mile on gravel and silt roads (not mapped here), to the beginning of this trail.
All trails have abundant goatheads and other spines. Tubeless and topped-up sealant is highly recommended. Take plenty of water and inflation (CO2 and pump). Large tires, for example 29'ers, and full suspension are best for the combination of steep, rough, loose conditions in this area.
El Cerro Bowl is the friendliest and most pleasant of the preserve trails. The trail tread is silt but the moderate grades make this a minimal obstacle. El Cerro North
and El Cerro Huning Ranch
traverse steep silt sections which are quite challenging and require some hiking.
The trail rolls along with a couple of short rocky and rooty sections which may require walking.
To do a loop on the upper mountain, the best direction is clockwise. Take the Bowl to El Cerro North
. Proceed up this 0.4 miles, then take a right onto El Cerro Connector
. Hike-a-bike a few hundred feet up to the plateau. Ride to El Cerro South
, which will take you around the south peaks area. Finally El Cerro West Escarpment
will bring you back to the beginning of Bowl.
Total loop distance is 5.2 miles. This is a tough ride requiring some hiking, but it's a nice challenge with great views for the adventurous.
The diverse riding conditions in this area reflect a diverse geologic history. The cerro (hill) is "two or more volcanoes of different ages." This volcanic rock provides the upper trails with steep slopes and abundant baby head rocks. Things have moved around too: "folding, thrusting, normal faulting, and uplift" have chopped up the volcanoes and caused the massive landslide at the north end.
The silty sand at lower elevations comes from eroding volcanics above, Rio Grande river deposits, and eolian (wind-blown) sources far away. (Ref: Love, et al. 1999, geoinfo.nmt.edu/staff%20/lo…