27.5“ (650B) mountain bikes
Mountain bikes with 27.5" wheels offer a great middle-ground between the agility of 26" and smooth-rolling characteristics of 29" wheels for mountain bikes. Light, sturdy and manoeuvrable enough to negotiate tight corners and quick to accelerate, yet still big enough
to roll capably over roots and other debris, 27.5" has all but replaced 26" for most genres of mountain biking. These days you'll find mountain bikes of all types fitted with 27.5" wheels, with the same model often available in 27.5" and 29" formats.
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