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What is 650B:

27,5 or 650B was the first rim diameter at the beginning of mountain-biking sports. The former downhill bikes were so called “Clunkers” with which at Mount Tampalais the first downhill races were held. They moved to 26-inch wheels and tires, as there was already for this standard balloon tires, which were more appropriate for the terrain.

Technical characteristics of 650B:

A 650B wheel is about 30mm longer than a 26 inch diameter wheel - therefore arose an established tire width of 50mm a circumference of 2147mm. Compared to a 26 inch with identical tires, a wheel circumference of 2069mm and a 29 inch with 2267mm.

The advantages of 650B are:

- Lighter and torsion-stiffer 29” as a "wheel set
- Easier to accelerate than a 29" wheelset as the wheelset is lighter (outer rotating mass)
- Smoother running of the bicycle
- Improved rollover behavior as a 26" wheel
- The wheel is due to the higher surface pressure has more stability when curving (advantage in tight, slow switchbacks) as 29"

The 650B is not a compromise to 26 and 29 inch. It combines the advantages from 26” (Weight, Torsion-stiffness and agility) with the advantage of the 29” wheel (Smoother running, rollover behavior and higher curve stability). The future for “All mountain” riders!

Compatibility:

For established MTB frames with 26 inch wheels and tires with freedom up to 2,4” the 650B rims are upgradeable. We assume a tire width of about 2.1 inches with 52-584mm or “ETRTO” Standards. For wider/ higher tires this could cause compatibility problems (touching the fork crown, bridge or dip tube at the rear of the seat tube/ saddle tube). In such cases it is necessary to reduce the rear fork thrust internally by approximately 10mm to maintain a consistant dimension and a suspension with less compression value should be built. Overall, it's easier to adapt on the geometry of spring mounted 650B wheels than 29" (Due to pedal kickback).

Available tires (From January 2012):

Kenda Nevegal (Available at TUNE!) 2,1 and 2,3 inch
Schwalbe Racing Ralph (Available at TUNE!) 2,25 inch
WTB Wolverine 2,2 inch
Pacenti Neomoto 2,1 inch
Pacenti Quaismoto 2,3 inch

For further questions regarding 650B tires, please call us or write us an E-mail. Or just have a look at our know how section on “TUNEPEDIA”.