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BIKERUMOR.com 2009 SEA OTTER CLASSIC COVERAGE: Zipp’s new 303 wheelset is “Ready for Anything” and was designed with the cobbles of classics like Paris-Roubaix in mind.
Despite being wider and taller, their weight is the same as the ’08 303 wheelset, and Zipp claims they’re more aerodynamic!  Built on their ultralight 88 and 188 front and rear hubs (named for their weights), the entire wheelset weighs in at a svelte 1182g (529g F / 653g R).  The new hubs have 17mm axles with taller flanges, which improves the wheel’s stiffness.
The diagram on left shows the substantial increase in rim profile from ’08 to ’09.  They gained 4.1mm at the rim edge, 4.1mm at the widest part and a slight 0.9mm more depth.  They have 18 spokes in the front, 24 rear, and the Sapin CX-Ray bladed spokes use external nipples for easy serviceability.  Note the angled brake track on the rim profile, which Zipp claims provides better modulation.
Hit ‘more’ for lots more pics and details…
Both the rear (above) and front (below) wheels have adjustable bearing load via small outside clamp bolts.  Simply loosen them, tighten the axle to the desired load with an allen wrench, then tighten the bolts on the outside to keep it where you set it.  The additional benefit of this design is the aero “tear drop” shape the clamp makes.  Position it appropriately before tightening the skewer and you’ll be just that much faster.
No unnecessary material to add weight leaves the dish where the spokes mount revealed on the drive side.
The blunt rounded profile is obvious from a top down view.  The rim bed was redesigned to protect against tire damage and make mounting tubular tires easier.  They use Zipp’s Carbon Bridge with Kevlar to increase impact resistance.  The wider rim actually relaxes the radial stiffness to help them soak up bumps better without reducing lateral stiffness..so they’re stable but comfortable.
The sidewalls get Zipp’s signature ABLC dimple pattern to aid aerodynamics.  These wheels are supposedly 12 seconds faster than the prior model over 40km with no additional side force.
Built as the ultimate all-around racing wheel, they’re intended for triathlon, cyclocross and punishing road races everywhere, but they’re comfortable and light enough for everyday riding.  All 303 wheels are handmade in Speedway, IN, USA.
