New Zipp 303 Firecrest carbon clinchers are radically wider and way lighter

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Hot on the heels of the midrange Zipp 303-S disc-brake carbon do-everything road wheelset that was introduced a couple of weeks ago comes the redesign of the company’s workhorse flagship, the 303 Firecrest. Like the 303-S, the new wheels are progressively wide and impressively light, although the 303 Firecrest now takes both of those traits and turns them up a few notches.

Rim depth has dropped slightly, from 45 mm to 40 mm, but the internal width has increased dramatically, from 21 mm up to a whopping 25 mm (external width remains unchanged at 30 mm). But despite the big jump in internal width, the total weight has decreased about 300 grams, most of which is coming out of the rims. Where the outgoing 303 Firecrest Carbon Clincher Tubeless Disc-brake wheelset tipped the scales at a claimed weight of 1,655 g, the new one (which thankfully bears a much shorter name) plunges all the way down to an astonishingly low claimed weight of just 1,355 g.

Actual weight of my test set comes in slightly higher at 1,402 g (642 g front; 760 g rear), but that also includes rim tape and tubeless valve stems.

Rim depth has decreased slightly from the previous generation and now measures a modest 40 mm.

Now, that newly simplified model name is fun to point out and all, but there’s a significance to it as well. Where Zipp previously needed to call all of those details out explicitly to distinguish the wheelset from the legacy rim-brake version (which was also narrower and wasn’t tubeless-compatible), this new 303 Firecrest is now a tubeless, disc-brake, carbon clincher by default. There is no rim-brake version, nor does Zipp plan to add one.

Zipp is rocking the boat in other ways with this wheelset, too.

The new rim bed is very wide, but — as is the case with a growing number of carbon clinchers — it’s also hookless. And it’s not just tubeless-compatible, either; Zipp is actually specifically requiring the use of tubeless (or at least tubeless-ready) tires here, with a minimum printed width of 28 mm. You can still use inner tubes if you’d like, but that hookless shape means that whatever tires you use must have tubeless beads for safety purposes.

“Printed width” is a key phrase here. On a rim of this size, the actual casing width will likely be closer to 31 mm — and that’s as small as you’re supposed to go here.

Notice anything missing here?

There’s more.

Zipp is pairing the new 303 Firecrest wheelset with recommended pressures that will invariably raise a few eyebrows. At this point, there’s plenty of data to demonstrate that wider tires inflated to lower pressures will roll faster than narrower ones at higher pressures. Nevertheless, Zipp is now codifying the practice on the 303 Firecrest with suggested figures that are even lower than what many progressively minded riders are already running. Additionally, the maximum allowable pressure is just 72.5 psi (5 bar) — the same as on the 303-S — even for riders right at the 110 kg (250 lb) recommended weight limit.

It might be a tough pill for some to swallow, but Zipp’s pressure guidelines are rooted in some sound engineering, and it’s all part of what Zipp has tagged with the fancy-sounding Total System Efficiency (TSE) moniker.

Aerodynamic performance is still a high priority for the new 303 Firecrest – this is Zipp we’re talking about here, after all – and the general shape has evolved yet again, taking on more of a rounded “V” shape in place of the previous model’s somewhat ovoid cross-section. Naturally, Zipp’s trademark dimples are still intact. But with this TSE philosophy, the company is now paying attention to a lot more than wind tunnel results.

According to Zipp, those lower pressures and bigger tire cross-sections simply make for higher speeds. Rolling resistance is lower than narrower tires at higher pressures (especially on less-than-ideal tarmac), rider comfort goes up, and cornering speed improves as well. And of course, reducing weight never hurts when it comes to going uphill, either.

Zipp didn’t provide any objective data to go along with the release of the new 303 Firecrest, but the smoother transition between the tire and rim seems intuitively to be a good thing in terms of aerodynamic performance. Photo: Zipp.

Much of the responsibility for that maximum pressure figure lies with that newly hookless rim shape (and it’s a number that’s imposed on Zipp by one of the cycling industry’s governing bodies, not something Zipp chose). However, the hookless format also provides the key to lopping off all that weight.

Rim hooks are notoriously tricky to make out of carbon fiber, and they have to be generously reinforced to keep them from blowing out under high inflation pressures. Hookless carbon fiber rims can do away with all of that extra material, and as a nice bonus, they’re both easier to manufacture in general (i.e. the rims are cheaper to make) and easier to manufacture consistently to very high tolerances (i.e. the rims are better, too).

There are aerodynamic benefits to hookless, too. Without a thick hook at the interface between the tire and rim, there’s a smoother transition between the rim and tire casing.

Without question, you can expect more wheel companies to move in this direction.

The hookless layout will likely be more than a little controversial, but no one will argue with Zipp’s new Tubeless Made Easy rim bed shape, which makes for easier tire installation, removal, and seating without the need for a compressor — and yes, it works as advertised, at least on the variety of tire samples I’ve played with so far.

The new “German designed” ZR1 DB hubset features large-diameter aluminum hub shells and variable flange sizes to help improve the spoke bracing angles.

Zipp anchors all of this around a new ZR1 DB hubset, which features a six-pawl driver and 5.5° engagement speed, Center Lock splined rotor interfaces (there is no six-bolt version), 12 mm front and rear thru-axle end caps, and conventional J-bend spoke flanges. Connecting everything together are Sapim CX-Ray bladed stainless steel spokes and externally located aluminum nipples in a 24-hole, two-cross lacing pattern front and rear. Complete wheelsets will be offered with Shimano HG or SRAM XDR freehub bodies; Campagnolo bodies will be sold separately.

A big change

Regardless of your reaction to the 303’s dramatic turn here, it’s important to note that Zipp is hardly the first to head in this direction. Enve arguably started the trend with the (admittedly superb) SES 4.5 AR Disc wheelset. Roval’s Terra CLX is also similarly wide (albeit subtly hooked), and smaller companies such as Hunt have fully latched on to the wider-is-better philosophy. And no matter who deserves the credit for kicking things off, there’s plenty of data out there to support the notion that wider wheels and tires are not only more comfortable, but also just plain faster.

Perhaps best of all, Zipp isn’t charging a premium for the big boost in performance. On the contrary, the new 303 Firecrest is substantially less expensive than the model it replaces, despite the fact that the carbon rims are still molded at Zipp’s headquarters in Indianapolis, Indiana.

Retail price for the set is US$1,900 / AU$3,349 / £1,600 / €1,800. Wheelsets should be available for purchase effective immediately.

www.zipp.com

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