Question: what size are mountain bike tires?
Answer: Mountain bikes are currently built in one of three main diameters: 26”, 27.5” (650B) and 29”. There is also a growing trend for 27.5+, 29+ and Fat Bike wheels which allow the use of specific high air volume tyres. Less common is the 24″ wheel which tends to feature on kids mountain bikes or dirt and jump bikes.