One of the few neighborhood mountain trails in the Seattle area still open to mountain bikers is Tiger Mountain. Thus, it's quite popular. The trail has a lot to offer: The forest roads lead up to the singletrack, which in turn leads to the woods, over technical trails shaded by a thick canopy of trees. The singletrack at Tiger Mountain is a great training ground for those learning how to ride technical trails and is especially challenging on wet days. Preston Railroad Grade is also fast but more technical than the Summit Trail, with roots, rocks, some gnar sections and some switchbacks. It requires very little pedaling in the downhill direction, but can be ridden either way. It's a challenge in the climbing direction! Blue Square on the way down, Black Diamond for the way up.