The rear wheel is where deep-section aero usually gets expensive in weight, and it's also where drivetrain compatibility decisions get made. Zipp's 808 Firecrest Tubeless Disc Rear Wheel answers both: 883 grams with thru axle and freehub installed, no tape or valves , built around an 80mm unidirectional carbon rim with a symmetrical profile and adhesive decals rather than paint. Total System Efficiency is the design framework — Zipp's stated goal was a significant weight reduction over the previous generation while treating wind resistance, gravity, rolling resistance, and vibration losses as a single problem rather than four separate ones.

The rim is hookless and tubeless-only. It measures 80mm deep with a 23mm internal width and a maximum outside width of 27mm , which puts the tire and rim close to flush and keeps the aerodynamic surface continuous through the transition. The Firecrest shape handles crosswind stability, and ABLC dimpling manages airflow across the rim surface. Road Bike Action's testing noted that the spoke nipples sit closer to the hub on a reinforced section of the rim profile, reducing the radius at which mass sits — the wheels accelerate more like a 1300-1400 gram set than their static weight suggests .

Tire selection is not optional here. Zipp specifies ISO/TSS compatible tubeless tires in 28-32c , and maximum tire pressure is 73psi/5.0bar with a maximum recommended system weight of 250lbs/114kg . Hooked-bead clinchers and non-approved tubeless casings are outside the operating envelope. If you're coming off a hooked rim with a favorite 25mm race tire, plan on replacing it before the wheel arrives.... Read More