We've created two sizes of the B2. The B2-R is the 'standard' size that fits most any bike, and the B2-SM is an ultra-compact version for smaller road bikes.
The B2-R will fit most drop-handlebar bikes (road, gravel, cyclocross) up to ~61cm. Larger road bikes may fit depending on specific geometry. If you're unsure your bike will fit, please email us with the size and model of your bike or bikes for personalized sizing recommendations.
The B2-SM will fit road bikes up to 56cm. Smaller sizes of gravel and cyclocross bikes may fit depending on specific geometry.