Cervélo Aspero-5 Force eTap AXS 1 review

The definition of gravel riding - and therefore the best gravel bike for the job - changes depending on who you ask. It's certainly more common to find bikes marketed as do-it-all machines, capable of everything from multi-day bikepacking trips to offbeat, off-road adventures than it is to find them touting increased aerodynamics and a lower weight.

However, Cervélo’s Aspero-5, launched earlier in 2021, sticks to very traditional aero bike claims: that it’s lighter and faster than the previous model. In Cervélo's own words it's a bike designed to 'haul ass, not cargo' and is unashamedly marketed as a racing bike, for off-road roadies.

This bike's design is a melting pot of tube shapes that are distinctively ‘Cervélo’ and drawn from the likes of the Cervélo Caledonia, R3 and S5, all pedigree bikes in their own right. 

The frame

Although the bike hasn’t changed in its looks since its first appearance back in 2019, Cervélo does claim that it’s both lighter and faster than the original Aspero to the tune of 32g of drag and a 10 percent decrease in weight. Our test bike weighed in a very competitive 8.3kg. 

While the brand claims there have been savings in the frame’s tube shaping - all of which comes from its reported extensively aero tested, pre-existing tube library - most of the efficiencies are the result of completely integrated cable routing. 

Although aerodynamics is not new to gravel (the 3T Exploro claimed to be the first ever 'aero' gravel bike), it certainly might not be everyone’s key consideration when it comes to gravel. However, if you spoke to the pro racers at an event like Unbound gravel - the exact type of race this bike was designed for - it would certainly be theirs. Plus, it wouldn’t be a Cervélo without some degree of aerodynamic tuning. 

The bike’s geometry sheet tells a story of a chassis built for off-road riding but tuned for going fast. The Aspero-5 has a relatively steep head angle of 72 degrees. That’s half a degree steeper than the Specialized Diverge but a wheelbase of 1027mm in a size large which is a fair whack shorter than the equivalent Specialized model. This makes it punchy and fast but a touch less stable at high speed. The top tube length of my size large also measures in at 575mm as opposed to the standard 560mm. Partnered with the slightly longer reach of the SRAM eTap hoods, this extra reach, was the first thing I noticed when jumping aboard. I’d actually swap a shorter stem which would allow for greater comfort and sure up the bike’s handling, too. 

The frame’s chunky tubing and wide downtube also give the bike real punch when riding on the road and wider, more open gravel trails. Although super stiff, it’s clearly not just a road bike that has been given a bit more clearance (and trust me, I've ridden plenty of those from the early days of 'gravel'). It feels tough and ready to take impacts on burlier trails.

Cervélo’s trail mixer system, a switchable dropout that tweaks the forks position by 5mm, remains from the original Aspero, that allows you to run either a 700c wheel or a 650b wheel with a chunkier tyre without altering the geometry. As the former, the bike can accommodate 45mm tyres but that increases to 50mm when in 650b form. 

The build

My SRAM Force eTap AXS equipped, carbon wheeled shod Aspero-5 turned many heads out on the trails. There were those admiring its Gucci qualities and frankly stunning ‘purple sunset’ paint job and there were those who watched with mirth as I rode by, wincing at every downtube rock strike. Truly, the Aspero-5 is the closest I’ve come to having a bike that looks too good to ride.

It’s certainly every bit the image of the gravel race bike. Those Reserve wheels, an in-house brand ported over from mountain biking, are carbon fibre and lightweight. With a 24mm internal rim width they’re wide, tubeless ready and have proven impressively bombproof. Elsewhere, the Quarq power meter is a very top end touch for a discipline that has only recently started grappling with the idea of wattages and the bike has electronic gearing in the form of a SRAM Force eTap AXS groupset. The complete bikes only ship with electronic gearing, in case you were wondering what end of the price spectrum these bikes sat. 

My test bike paired a 36t chainring to a 10-36t cassette, it’s a setup that gives, in theory, the best of both worlds – a 1:1 ratio for climbing and a big gear for turning over on the descents. For my riding on my home trails in London it was perfect but attending my first gravel group ride in Scotland for a series of video shoots I was a little worried to see my fellow riders pairing super wide SRAM mountain bike cassettes to their single rings. Noting my quizzical looks, one rider told me the standard climbing ratio was 400m for every 1 hour of riding. Fortunately, Cervélo does have a 2x Shimano GRX offering (with new XPLR launched from SRAM there is now also a 40T/10-44 build, too - Ed) that provides a greater spread of gears. Unfortunately, I wasn't riding it. In the end, I pulled through, mostly because the wide forestry roads were lenient enough in their gradients but if you ride mostly technical single track or 'aggressive' gravel climbs you might want to spec up. 

New for the release of the Aspero-5 is the carbon AB09 flared handlebar which runs the cables through a channel underneath and then internally through the stem and into the headtube. It’s a neat solution, the same as that on Cervélo’s road bar and which worked well when I tested the Cervélo Caledonia. It is partnered with split spacers which takes some of the sting out of adjusting the bike’s stack height. Of course, there’s a degree less integration on the wireless SRAM build tested here. 

Other neat details includes the bike shipping with a bento box equipped to the top tube mounts and an integrated computer mount outfront.

The ride

I need a gravel bike that handles a long tarmac slogs as well as the varying conditions UK trails can present at anytime of the year. It needs to be able to hold its speed on the road but also feel nimble and agile off road. The Aspero does the former admirably, its carbon frame holds speed like the best performance road bikes I’ve tested, with the carbon wheels doing their part, too. The Gravelking tyre’s skinny 37mm profile minimises their damage out on the road, too. 

However, that frame stiffness does make itself known on tight and twisty singletrack. Every impact is felt through the carbon bars and carbon frame and every root you catch or rock you roll over is a knock you feel. The bike’s steeper head angle makes it twitchy on steeper, more technical descents and it is a bruising ride, but at least the bike feels tough, I was confident riding drops and rollers.

Roll the bike along wider gravel roads and access roads, the types the forestry use in Scotland, and the Aspero-5 suddenly makes complete sense. On this terrain, where gravel rides are closer to road rides in their speed and style, the Aspero-5 absolutely shines. On one particularly fast group ride I found myself whipping along in the bunch, tucked in the drops on the descents and cranking up the climbs on the other side. Here, the Aspero’s super stiff carbon frame does everything it's meant to; straining ahead, its wide bottom bracket propelling you forward with every turn of the cranks. The bike’s slim 8.3kg weight also helps. 

Admittedly, I found the limit of the Gravelking tyres on this terrain and I was wishing for tyres with a little bit more of an edge to them. I also found myself wishing I’d bothered to set them up tubeless – Cervélo ships this bike with tubes. This also applies to riding tight and techy singletrack, where you’ll definitely want more grip than the Gravelkings can offer. 

Value

As a model range, the Aspero-5 absolutely represents the top end of the gravel market. At £8,199, the Cervélo Aspero-5 SRAM eTap AXS tested here is eye-wateringly expensive and the entry point of the Aspero-5 range. Above it sits a Shimano GRX build and the third, a SRAM Red eTap AXS build tops out at £10,799. 

For anything lower there’s the Aspero range which starts at £3190, which isn’t exactly budget. You’ll also drop the carbon handlebar and carbon wheels, too.