Mountain biking was originally the one phrase we needed when referring to riding a non-road bike on trails. However the phrase has now become a general umbrella term for a wide and growing variety of sub-categories, depending on the type of trail, the vertical change, the general speeds, whether it’s mostly up, down or equal, and so on. Right near the middle of that spectrum is the Trail bike category, sometimes referred to as All-Mountain. These bikes blend some of the quickness and lightweight from the XC side with the descending and technical-trail capabilities of the more gravity-oriented bikes like Enduro. While they generally don’t do either as well as their more focused brethren respectively, a Trail bike will generally descend better than an XC and climb/accelerate/handle better than an Enduro.
These days there’s quite a spread of Trail bikes available, with a few subcategories thrown in just for fun. In general they feature 120–150mm of travel, with most in the lower range; geometries are less aggressive than their more speed-centric cousins, with slack head and seat-tube angles providing a more relaxed, rearward position in the cockpit. Almost all recent models have 27.5-inch wheels with a few 29ers remaining. At this price range, there are some alloy frames, but most feature carbon frames (some with alloy rear triangle). The big new trend in these bikes is the Plus bike — generally 27.5” wheels with tires up to 3-inch wide (much wider than traditional tires which max out around 2.5 inches). Almost every brand now offers Plus bikes, and most fall in the Trail category. These wider rims/tires provide a huge benefit in traction and cornering along with a cushier ride over the smaller bumps. Many brands are even forgoing rear suspension thanks to the added “suspension” of Plus tires. The downside of course is considerable added weight and rolling resistance, both especially noticeable on smoother climbs and flats.