Most mountain bikes today are offered in one of two wheel sizes: 27.5˝ (also know as 650b) or 29˝ (called 29ers), with traditional 26˝ wheels reserved for dirt jump, freeride and kids’ bikes. These widely used measurements refer to the tire’s diameter, and are typically paired with a tyre width in inches when written out, (i.e. 29 x 2.0, 27.5 x 2.4, 29 x 2.8). Here at Trek, we’ve been studying wheel size for nearly two decades alongside mountain bike legend Gary Fisher, and our breadth of experience has provided unique insights about the riding characteristics and best applications for each mountain bike wheel size. This guide provides a general introduction to the ride feel and characteristics of each wheel size that we offer to help you find the MTB that best fits the way you ride.

Cross country & Smart Wheel Size

Our years of research have told us that 29˝ wheels are the most efficient choice for most bikes and riders. However, we’ve also learned that pedalling efficiency and power output in the saddle depend on getting the right bike fit and positioning. While our trail bike line-up includes a wide variety of wheel and tyre options for all types of riders, we keep things simple with our cross country mountain bikes, using an approach called Smart Wheel Size. Each frame size is paired with the wheel that best fits the rider and sets them up for optimal efficiency and power transfer. We pair 29˝ wheels with 17.5˝ and larger bikes, and better-fitting 27.5˝ wheels for 15.5˝ and smaller bikes. Riders looking for the fastest and most efficient XC bikes will be ready to roll with Smart Wheel Size.

山道自行车：尽在掌握

很多全避震山道自行车车手将骑乘品质而不是效率放在优先，因此我们的山道自行车系列将提供多种车轮及车胎选项。首要的考虑因素就是您更重视 27.5˝ 车轮带来的有趣、精准的感受，还是 29er 自行车的速度与翻覆能力。除了 27.5˝ 对比 29˝ 问题，现在我们还需要考虑另一个可变因素：大尺寸车胎。大尺寸车胎是指宽度为 2.8˝ 至 3.0˝ 的车胎，这种车胎可以提供更大的牵引力以及更好的翻覆能力，令其成为入门车手或将抓握性能优于其他任何因素者的选择。