Is this the most aerodynamic gravel bike ever made? Cervelo claims all new Aspero-5 will save you 37 watts vs previous version

Gravel racing is perhaps the most exciting sector of all cycling disciplines at the moment, with it gaining entrants and spectators on an impressive scale. And with all of that hype, it comes as no surprise that the bikes are getting mighty techy and Cervelo has weighed in with its brand new Aspero-5, a bike the Canadian brand boasts is the most aerodynamic gravel bike ever made.
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The Aspero-5 goes big on aero
Aero gravel is the biggest story at the moment, with rugged gravel bikes taking cues from their road-going counterparts, and the new Aspero-5 is certainly no outlier in that respect. In fact, it's heavily influenced by the S5, the brand's 'max aero' road bike (that will be updated imminently according to our pals at road.cc). This can be seen throughout the Aspero-5's frame, as it uses a similar top tube angle as well as a deep bottom bracket and seat gussets.
We're told the Aspero-5 is so aerodynamic that it can save you 37 watts over an hour versus the previous Aspero, and 34 watts against its nearest competitor (Cervelo doesn't say what that bike is). Those are very lofty claims, and we haven't been supplied any hard CFD or wind tunnel data from Cervelo to back them up, but the brand does partner with Reserve wheels to design and develop all of its aero bikes. Reserve travelled the US to map many different wind conditions to "replicate real world conditions in the wind tunnel", according to its web page, and the WorldTour pro road cycling team Visma Lease a Bike use its facilities to perfect their position and equipment choices.
It's lighter too, according to the brand. Despite the frame being weightier at 1,025g, as opposed to the old bike's 990g, weight savings have been made at the bar, fork, seatpost, and stem. Downtube storage has also been added into the mix, which adds 65g to the overall weight, says Cervelo.
Aero gains run deep, as the frame isn't the only facet of the bike to go aero. Cervelo says the new HB16 handlebar saves you 5.7 watts compared to the outgoing HB16/AB09. Interestingly, it's not a one-piece bar and stem combo, so it still features the customisation possibilities of stem length and rise, while reaping the rewards of an aerodynamic design. This bar measures 40cm wide at the hoods (making it safe from those pests at the UCI) and 46cm wide in the drops. Of course, the bar can accommodate fully and semi-internal cable routing, and there's a neat computer mount.
In pursuit of all of the gains, Cervelo has tweaked the front brake mount at the fork. Saving 38 grams, apparently, the new brake mount can run a 160mm rotor without an adapter, and the threaded insert of old has been replaced by a co-molded threaded insert, shaving more grams.
Geometry adjustment through tyre sizes
Cervelo has recognised recent trends in mixing tyre sizes at the front and rear, and has used it as a bit of a geometry-adjusting feature. The brand says that a smaller front tyre and larger rear tyre (40/44mm, for example) steepens the angles and reduces drag while achieving 'quicker' handling. A matched tyre setup slackens the angles, and should make for more confident handling over technical terrain.
With a matched wheel size, riders can expect a 71.6-degree head tube angle, a 422.5mm chainstay, a 72.6-degree seat tube angle, and a 395mm reach, although the brand doesn't state which size that'll be on.
Throw a wider rear tyre into the mix, and that achieves a 72-degree head tube angle, a 73-degree seat tube angle, and a 399mm reach while retaining the 422.5mm chainstay.
Speaking of tyres, the Aspero-5 has space for up to a 45mm wide tyre at both ends.
Finishing up the feature list is clearance for a 52t chainring, UDH compatibility, and no clearance issues with dual-sided power meters. There's then a T47A bottom bracket.
Three builds, one frame
Cervelo is offering the new Aspero-5 in three builds, with one equipped with the new SRAM Force AXS, another being built with Shimano GRX Di2, and the top-of-the-range model getting SRAM Red AXS. There's also a frameset available for those who want to build the bike up to their specs.
As for prices, expect to spend £5,000 on the frameset, £8,000 on the Aspero-5 SRAM Force AXS 1 and GRX-equipped builds. For the SRAM Red AXS 1 bike, be prepared to start rummaging for a cool £10,000 down the back of your sofa.