Mountain biking has its own language — and when you’re new, it can feel like riders are speaking in code. This guide breaks down the most common words, phrases, and bits of jargon you’ll come across both on the trails and in the MTB community. 29er A mountain bike with 29-inch wheels. 650b / 27.5 A wheel size. Actual diameter is slightly under 27". Attack Position A ready stance with elbows out, hips back, and heels down for maximum control. Bail Jumping off your bike deliber