AX-Lightness

Premium 55T Tune Hub Tubular Wheelset

AX Lightness's Premium 55T Tune Hub Tubular Wheelset is designed to plow through the wind with the same enthusiasm with which Admiral Farragut once famously confronted torpedoes. Given that he was in a boat at the time, the Admiral's storied bravery may have been on the foolish side; however, the Premium 55Ts benefit from the same fluid dynamic considerations AX-Lightness pours into its motorsport designs, so their wind-be-damned attitude is based purely on science, not hubris.

Most 55mm rims offer recognizable benefits when the yaw angle is low, but they turn erratic when the angle gets obtuse, throwing the bike — and its rider — around the road. As illustrated by the peculiar shape of their rims, the Premium 55Ts don't rest on these kind of wind tunnel-only aerodynamics. The cross section swells to 26 millimeters at its widest and terminates in a blunt, round shape rather than a point, which keeps unruly laminar air in check as it travels across the rim's surface. This eliminates pockets of dead air while rolling forward, and it also refuses crosswinds any purchase, keeping the handling consistent and predictable under conditions turbulent enough to sink any other 55-millimeter wheels.

While that combination of aerodynamics and handling in crosswinds eliminates the typical drawbacks of deep rims, stiffness and weight are still important aspects of any racing wheels. AX-Lightness uses a carbon weave for the rims because, unlike the ubiquitous unidirectional fibers of late, a woven fabric has load bearing properties that recommend it for a wheel's rim, which experiences dynamic directions of pressure as it spins. This means efficient power transfer and torsional stiffness can be achieved with less material, which in turn results in less weight.

The Premium 55Ts enjoy the universal technology of rim construction that defines AX-Lightness, including AX-Lightness's Seamless Brake Surface (SBS). SBS uses high-pressure autoclaves to combine the wheels' layers with gas, eliminating any imperfections down to the smallest edge for a one-piece brake surface that's both seamless and virtually free of imperfections. The rims are nearly perfect on a microscopic scale after they're cured, so there's no shuddering while braking during descents. After curing, the wheels are also tempered, which realigns the resin crystals to drastically increase the braking temperatures that they can withstand before the carbon softens and deforms.

The wheels' reliability is boosted by Spoke Reinforcement Technology, which creates the spoke holes during the manufacturing process itself. There is no post-production drilling once the rims come out of the autoclave, so there's no additional structural weakness. As a result, the Premium 55Ts can bear five tons of nipple resistance, which AX-Lightness takes advantage of by tensioning the spokes to 1300 N.

The hubs are also German affairs, straight out of the Black Forest: Tune's Mig45 front and Mag150 rear. The flanges are reduced and wrapped in carbon, which makes for a lighter hub. Except for on the rear drive side, the flanges aren't oversized like you'd expect from a low-weight, high-power wheel, but the carbon reinforcement serves to stiffen them up.