Giant International is launching three wheel sizes for their 2014 mountain bike lineup: 26", 29", and 27.5". They argue for the 27.5" wheel size based on three reasons: weight, efficiency, and control. 27.5" wheels are lighter than 29" wheels but not much heavier than 26". They roll over obstacles better than 26" wheels and accelerate faster than 29" wheels. 27.5" wheels also have more traction and a stiffer frame and wheels than 29" wheels while allowing for efficient frame geometry like 26" bikes. Giant International believes the 27.5" wheel size is the future.