Zipp is renowned for producing light and fast wheels, but the new Sub-9 is something of a revelation.
After wind tunnel testing the Sub-9, Zipp says that it discovered that at a wind angle of 15 degrees the drag reading hits negative drag with a -80g reading. Instead of creating drag, the disc acts as a sail propelling the wheel forward.
Taking lessons learned from the new 1080, the disc has taken on a new shape resembling that of the 808 rim, with a vertical wall instead of spokes controlling the airflow as it comes off the wheel. To finish the disc, Zipp?s golfball dimpling technology is
Not just improving on the drag figures, the Torodial bulge of the rim acts as a spring, absorbing road bumps to keep the tyre in contact with the tarmac.
A new carbon bridge, designed to improve impact resistance by 25 per cent, includes Kevlar threads stitched into the bridge of the rim in a co-axial helix stitch, which binds the layers of carbon together in a three dimensional plane.
Don?t expect them too soon, though, as production is very limited at present, but they should hit the market later this year.