The Firecrest 303 is one of our all-time favourite wheels. The balance of low weight, stiffness and aerodynamic stability makes them a great – albeit expensive – all-rounder. The tubular 303s have also fast become a favourite in cyclo-cross. So with discs appearing more in ’cross and on the road Zipp needed to adapt its wheel.
But it hasn’t just taken the existing wheels and stuck on a disc hub; Zipp has gone back to the engineering bench to ensure its new 303s will cope with the increased forces that disc brakes generate. Gone are the front wheel’s 16 radial spokes – its 24 crossed spokes now match the rear. That’s to eliminate the chances of the rim continuing to rotate when the hub is stopped by a disc brake. Hub internals have been beefed up, both wheels gaining larger stainless steel bearings, the rear also getting a new custom cartridge in the hub shell for off-road durability. This does increase weight, from 1,579g for standard 303 clinchers to our pair’s 1,678g.
The hubs use the International Standard six-bolt rotor attachment, which makes them compatible out of the box with both SRAM and Avid. Formula, Hope and TRP are among those also offering six-bolt options, while Shimano users will need to buy compatible six-bolt rotors.
Our wheels have been tested on road, ’cross and gravel bikes, off road and on. On tarmac we used 25mm tyres, off road we tried 32mm ’cross clinchers – but the best result was achieved using Challenge’s Strada Bianca 30mm road tyre. This is perfect for the 28.5mm wide rim, the volume and shape combining comfort and the ability to maintain the 303’s blistering pace. The wheels survived a hammering too, post-ride testing on a wheel jig showing that our test rims stayed true.
The result is that these are the best off-the-peg disc wheels we’ve yet seen. Very expensive, yes, but the quality of the ride justifies the money.