If there is one thing that carbon rims are universally criticised for, it’s wet weather brake performance. Perhaps no longer with the Zipp 404 Firestrike.
Zipp has long been aware of this and worked hard on both brake pad compound as well as the actual braking surface – so that makes the news of the Showstopper brake track (its choice of name, not ours) all the more interesting.
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Zipp claims that the brake surface change means that wet weather stopping performance is now equal if not better than the leading alloy rims – which in our books is a big statement. This substantial improvement is brought about thanks to tiny surface swipes in the actual brake surface, these moulded-in scoops act like the tread on a car tyre and dry the pad quickly in wet conditions.
Loaded with refinements, the 404 Firestrike sits above the Firecrest wheels, which remain in the range. As you might have guessed from the small name change, the Firestrike indicates a different rim profile but one that still uses Firecrest technology and is covered under Zipp’s existing patents. The re-profiled rim is now wider by roughly 1mm all round. Giving a total width of 26.4mm at the widest point of the brake.
This wider profile has further advantages in that as Zipp found with its original wider profile the rim is less susceptible to sidewind forces steering the wheel for you, part of the new profile aim was to reduce this still further – something Zipp claim to have done.
Sitting in parallel to this is that they’ve also reduced the side force the wheel experiences in cross winds by a whopping 34%. A good proportion is because of the wider rim but they also looked at the dimples that have come to characterise Zipp rims. By looking again at dimple size and spacing, the Indianapolis aerodynamicists have tuned the dimples to shed air vortices more frequently, which also contributes a worthwhile amount.
Thanks to the wider brake track, the tyre now sits more squarely on the wheel giving it a larger footprint and increasing grip but as there is less flex in the carcass of the tyre, rolling friction is reduced at the same time.
All these small changes have added up both in terms of performance but also in terms of manufacturing cost so new Firestrike 404’s have increased in price too, and cost £2,750 for a pair.
Full carbon stem from Zipp with the 100mm version weighing 167g