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Basic Guide: 27.5" Mountain Bikes

How perfect would life be if one size fit all? Unfortunately, people come in all shapes and sizes, and not one rider attacks the trail alike. From downhill and cross country, to riding country gravel roads, a bike is designed specifically for the participant and the action that will take place. One consideration to every bike design is size of its wheel.

There are three wheel sizes available to adult mountain bikers:

  1. 29-inch
  2. 27.5-inch
  3. 26-inch

The advent of the 27.5-inch wheel (also known as 650b) marked this third choice for mountain bikers. There are distinct advantages to each size, so let’s outline a few for the 27.5-inch wheel.

  • An Improved Angle of Attack: for cross country and trail or all-mountain style riders, a 27.5-inch wheel will roll over faster and easier than a 26-inch wheel. The larger the wheel, the smaller the obstacle relative to the wheel. Sounds easy enough and when you encounter a log or a rock, you quickly learn that this is true.

  • Improved Agility: for the rider that likes to be aggressive on the trail, the 27.5-inch wheel may be the perfect size. Compared to a 29-inch wheel, the 27.5-inch is easy to get off the ground and get some air, and it’s easier to maneuver through winding and tight singletrack lined with precarious branches.

  • A Lower Center of Gravity: this means more stability byway of the relative position of the bottom bracket to the wheel axle. Your body will feel more comfortable and centered as a result.

  • A Better Fit For Average Height Riders: the 27.5-inch wheel simply isn’t as physically large and cumbersome as the 29-inch. Sounds simple enough, but it means that everything isn’t as tall or bulky (frame, wheels, etc.), so that an average sized rider can throw their leg over the frame comfortably, which has always been an obstacle for a shorter rider that wanted to ride a big wheeled bike.

  • Improved Clearance: Bigger bikes mean bigger problems with tire clearance. Not so with the 27.5-inch wheel. The 27.5-inch provides plenty of tire clearance, so you can throw on just about any tire width within reason.


No matter what bike you’re in the market for there’s a wheel size that will accommodate your desired riding style. If you’re looking to ride cross country, all-mountain or just want shred some singletrack and need a bike that will provide excellent performance over obstacles, yet still be manageable enough to get air and be playful, look no further than the 27.5-inch wheel.

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