Zipp is constantly working to improve their entire line of incredible Firecrest and NSW aerodynamic wheels through assessing engineering, design, bike and tire development. Innovations and improvements to the wheel line-up with featured clincher-tubeless rims that have more tubeless-appropriate internal and external widths, as well as improving strength and Zipp's tireless pursuit of Aero Balance (the combination of low drag and stability). To that end, the Zipp 303 NSW Carbon Clincher Tubeless Rear Wheel features an entirely redesigned rim shape that aerodynamically integrates wider tubeless tires for enhanced ride quality and performance. The 303 NSW now has a wider 19mm internal rim width and corresponding outer rim shape for aerodynamic optimization with 25mm tires and able to be efficient with 28mm as well.

The 45mm deep 303 NSW Carbon Clincher Rear Wheel was developed to be raced, but it is strong and resilient, with a smooth ride that makes this a great every day wheel. Training and racing on the same wheels equals incredible confidence and familiarity. Clincher and Tubeless tire options make tire management simpler and more cost effective than tubulars. With it's lower profile, incredible stability and 825 gram weight, the 303 NSW can adeptly handle corners at high speed, and spins up immediately as you power out and onward. Complementing the 19mm internal width is a brake track width of 26.4mm, and max width of 26.5mm, so riding tires from 23-28mm wide means you can maximize the tire/wheel aerodynamic relationship carried through the ABLC Sawtooth™ rim dimple patterning. This advanced NSW dimple design consists of 12 nodes that are precisely clocked to start aerodynamic shearing at a rate of 50hz at a rider speed of 20mph. Sawtooth induces small sheet vortices that shed at a low magnitude, but at a higher natural frequency, thus decreasing the laminar bubble effect on the aerodynamically shielded side of the rim’s profile to further reduce high yaw drag and improve crosswind stability while providing aerodynamic speed.

The stout, lightweight Cognition alloy rear hub has been built with a star-flanged straight-pull type hubshell that distributes the load placed on the hub flange away from the bearings in order to keep the Swiss steel bearings precisely in line with each other and the oversized alloy axle. This reduces friction and maintains pure rolling speed. Every watt of energy conserved or gained through design saves valuable seconds in performance terms. The real magic of the Cognition rear hub is in the new drive system. This proprietary Zipp design features a new Axial Clutch™ system with 36 points of engagement controlled with magnets. The magnets move and engage the light weight Metal Injection Molded (MIM) ratchet rings for unmatched reliability and consistent operation. The Axial Clutch system reduces drag by disengaging the ratchet mechanism when coasting. The magnets then re-engage once the rider starts pedaling again. The system is quiet, wonderfully efficient, and 100% reliable.

Zipp laces 24 Sapim® CX-Ray lightly bladed, straight pull steel spokes in a 2x pattern via Sapim's SecureLock external nipples. With the spokes disappearing into the hub, the overall effect is visually and aerodynamically very clean. The carbon clincher rim can easily handle the high tension required, and the wheel can easily be trued in the traditional fashion. Zipp's clincher technology is well proven and has made clincher use for events not only feasible, but common with today's top clincher tires like the Zipp Tangente series. Race ready tubeless tire options from 23-30mm are widely available and starting to make serious inroads into US domestic cycling and triathlon as the tire option of choice for racing and training. Zipp has engineered their own Tangente Speed RT25 and Tangente Speed RT28 tubeless tires to deliver the lowest rolling resistance, best dry and best overall cornering grip among major brands.

Rim braking with carbon wheels is a huge consideration for all cyclists, and Zipp's outstanding Showstopper™ brake track offers unparalleled braking and heat management through pairing of a directional, molded-in, texture with silicon carbide particles suspended in the surface resin in a molded groove pattern. That pattern has been matched with the surface and cooling channels of the included Tangente Platinum Pro Evo brake pads for incredible stopping power in dry or soaking wet conditions, in any terrain. The leading edge of the pad and first two channels efficiently wipe water and debris outward, cleaning and drying the braking surface, while the second two channels have maximum interference as the grooves create greater braking force without heat build-up.

Just to raise the bar a little higher, Zipp uses ImPress™ technology to apply graphics directly to the rim surface, giving the wheels an even stealthier appearance without mitigating the aerodynamics of the dimple structures. The NSW design has been featured on many race winning road and triathlon bikes. Now, you don't have to be a racing cyclist or triathlete to enjoy and benefit from the 303 NSW Carbon Clincher Rear Wheel. There are plenty of serious cycling enthusiasts who can push the capabilities of the 1500 gram complete wheelset. You truly can ride these wheels as your every day option. Now with larger tire volumes in both clincher and tubeless options, you get more durability and can smooth out the ride with lower pressures while maintaining speed, efficiency and stability.