Rollin' with the 29er and 27.5" Mountain Bike Tires.
Bigger is better when talking about mountain bikes, or their tires that is, the 29er is a popular industry favorite, but the 650b (or 27.5") is rising in popularity and are expected to outdo the regular 26" wheel standard.
The 29er refers to the outside tire diameter of 29 inches. Prior to the 29er the standard mountain bike tire was 26 inches in diameter. So, why go 29"? If you haven't heard. . . size really does matter. The 29ers maintain speed and a smoother ride while rolling over rough terrain. The larger tire also provides better traction due to it's larger contact area with the ground.
The 650B comes in right between the two at about 27.5". Cyclists are always striving to improve the ride and so the 650B was born. The idea behind the 650B tires are to provide all of the same advantages of the 29" tire with less of the disadvantages. The 650b still provides lower rolling resistance, better traction, and delivers a smoother ride without the geometry limitations, toe clearance issues, higher center of gravity, and suspension travel limitations. Whatever preference you may have, Bike Attack carries them both, so no worries.