Marin Alpine Trail XRThe all new Marin Alpine Trail series is the boldest and most capable line of Marin 's enduro bikes ever, built upon our most advanced, most adjustable frames to date. Series 4 aluminum MultiTrac 2 LT frames feature mixed 29 27. 5 wheels, 170mm front and 160mm rear travel, and the utmost in adjustability. Riders can alter the head tube angle and bottom bracket chainstay length, as well as run 29 rear wheels if desired. Bear Box downtube storage