The definition of what's considered “road cycling” has evolved to include gravel and dirt as well as pavement. At the same time, bikes are evolving to meet the fit requirements of smaller riders. Meeting these two distinct needs was the driving force behind the new Zipp 303 Firecrest 650b Carbon Clincher Tubeless Disc-brake wheel.
It shares the same proven innovations as the full line of Carbon Clincher Tubeless Disc-brake wheels. The difference is size. A 650b wheel has a 584 mm bead seat diameter rim vs. the 622 mm diameter of a standard 700c road rim.
Foremost, the 303 Firecrest 650b is an ideal choice when the pavement ends. The smaller rim size provides room within frames and forks for larger tires, 28 mm or wider, that deliver increased comfort, compliance, and cornering performance. With more tire between the rim and the ground, the overall wheel diameter including the tire is similar to a standard 700c wheel and road tire combination.
Back on the pavement, the 650b is a better fitting wheel for smaller athletes riding compatible frames. For too long, many smaller cyclists have trained and raced on standard 700c wheels, losing out on the advantages of a proper fitting wheel such as improved handling and the elimination of front wheel toe overlap.
Zipp's updated 650b rims have an internal width of 21 mm. The 303's 45 mm rim depth is an ideal option for every terrain or road surface. Designed to be tubeless compatible, this setup option allows you to run lower tire pressure for increased comfort and cornering grip along with a reduced chance of pinch flats. For added security, the rim bed features internal ridges to lock the tire's bead in place, even when ridden at lower tire pressures.
A new carbon fiber layup keeps weight low while maintaining the Firecrest Carbon Clincher's proven durability. To maximize aero benefit, Zipp's ABLC dimples extend all the way to the outer edge of the rim.
The robust 177D hub, paired with 24 Sapim CX Ray spokes, keeps the wheel stiff and responsive. To ensure compatibility with any bike, the versatile hub comes with swappable end caps to work with QR's and 12x142 mm thru-axles.
With the introduction of the 650b, the Zipp 303 Firecrest - now more than ever - is a wheel without limits.