29"

With a ETRTO of 622mm this is the largest wheel size currently in use. It is capable of rolling over terrain faster and smoother than smaller wheel sizes such as 26" and 27.5". For this reason 29" wheels are commonly referred to as the fastest mountain bike wheels size. Although 29" wheels tend to be slightly heavier, once they get up to speed they are able to maintain they're speed. From a stop, smaller wheels are able to get going faster due to being lighter but they aren't able to maintain they're speed as easily. 29" wheels are commonly found on cross country orientated bikes but are slowly expanding into enduro & downhill disciplines as well.