The Rock Rider 520 was designed and created in Suzhou, China, by a team of experts and cycling enthusiasts dedicated to designing our MTB Sport Touring line. Production was also done near Suzhou to be as close to our Decathlon stores as possible. Rock rider CGF Evo (Comfort Geometry Frame) 6061 aluminum frames for 27.5" wheels. Seat is 5 times more flexible than a standard frame thanks to a narrow 1.07-in. seat post. Low bottom bracket helps keep the mountain bike stable in turns and makes it easier to place foot on the ground. bicycle is easy to turn. Travel and an innovative fork stiffness adjustment based on the rider's weight (121 to 230 lbs.). Durable thanks to the materials and fabrication processes used.