By Stefan Abram
Zipp has rolled out its updated rim manufacturing techniques to its deeper section carbon offerings, with some huge weight savings as a result – up to a claimed 400g on a whole wheelset. The testing of the wheels has also seen a revamp, being carried out in the real-world with a rider and bike system of 85kg riding at a much more attainable output of around 280w.
Just as we saw on the shallower 303 wheels released in May 2020, the move to a hookless rim profile has not only reduced the weight but it has also simplified the manufacturing process. This in turn reduces the costs of producing the wheel – which are then passed on – as well as reducing the amount of waste created.
With the focus being to optimise for “Total System Efficiency”, these wheels haven’t made much of a concession to either rim brakes or clincher tyres. There is no option to have these rims with a braking track – they are disc brake only – and the hookless inner profile means that only tubeless tyres are compatible.
This is what Zipp bills as the “ultimate road racing wheelset”. It retains that distinctive saw tooth profile which was based on the pectoral fins of humpback whales, with the idea being to mimic the speed and efficiency that has naturally developed in the biosphere.
This puts the rim depth as varying between 58 and 53mm, yet still offering better aerodynamics than the new 404 Firecrest wheels which have an even 58mm deep profile. The move to a hookless profile for these rims greatly contributes to the saving of just over 400g (claimed) over the previous iteration of the 454 NSW.
Now, onto the outdoor testing. Zipp found that a bike-and-rider system weighing 85kg (187lbs) required 278w to maintain a speed of 40kph on these wheels with 25mm tyres – which is a 10w saving over the previous version of the 454 NSW.
At the heart of these wheels is the Cognition V2 Hubset, which has been reengineered with an updated Axial Clutch V2 mechanism. This reduces drag when coasting by disengaging the ratchet mechanism and using a wave spring to re-engage the ratchet when the rider starts pedalling again.
Although rim brakes and clincher tyres may be a no-go, there has been one – rather major – concession to technologies of the past, there is a tubular version of these rims as well. Demand from the pros meant that Zipp almost couldn’t not. Interestingly, though, the wheelset weight is actually heavier than the tubeless version, at 1,463g compared to 1,358g (claimed).
The rotor mounting is the centre lock design and the wheels are available with either XDR or SRAM/Shimano freehub bodies. A Campagnolo driver body is sold separately.
Pricing stands at $1,800 / £1,425 for the front wheel and $2,200 / £1,775 for the rear – irrespective of tubular or tubeless rim or XDR / HG11 freehub.
The 404 Firecrest arguably represents much better value than the 454 NSW – even if it doesn’t quite match the superlative stats.
At 58mm deep, it’s still highly optimised for aerodynamics, while the 23mm internal width rim is designed to pair perfectly with 25mm tyres and offer a flush interface between rim and rubber.
In Zipp’s outdoor testing, it was found that a rider/bike system weighing 85kg required an output of 286w to maintain a speed of 40kph on these wheels paired with 25mm tyres. This is a 4w saving over the previous 404 Firecrest wheels – but perhaps more significantly, it’s still actually a 2w saving over the previous version of the top-end 454 NSW wheels. Considering the price difference between those wheels and these, that’s a considerable gain.
The hubset here is different to the updated 454 NSW wheels, with the ZR1 DB hub specced instead. But depending on how more attention you like to lavish on your wheels, this is arguably a plus – the seal design has been updated on these to improve durability and longevity.
The weight, as you would expect, is a little more than the tubeless version of the 454 NSW – but at 1,450g (claimed) the 404 Firecrest is actually 13g lighter than the tubular version.
The hubs are centre lock disc brake mounting and come with either XDR or SRAM/Shimano freehub bodies, although a Campagnolo driver body is sold separately.
Pricing stands at $925 / £780 for the front wheel and $975 / £820 for the rear wheel, irrespective of freehub.
Intended for triathletes and time-trialists – although there’s nothing stopping you from popping a set of these on your road bike if you so wished – the 858 NSW wheels are essentially just a deeper version of the 454 NSW wheels.
The undulating profile varies between 77 and 82mm and is likewise claimed to improve not only the aerodynamic efficiency but also the crosswind stability. The hubset is shared with the 454 NSW wheels, the Cognition DB V2, and that same Axial Clutch V2 is present to reduce drag when coasting.
The wheelset has a claimed weight of 1,773g, is compatible with centre lock rotors and is available with XDR or SRAM/Shimano freehub bodies. A Campagnolo driver is sold separately.
Pricing stands at $2,000 / £1,786 for the front wheel and $2,400 / £2,144 for the rear, irrespective of freehub.
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