Avona Callis first ride review: German brand's debut gravel bike is fast in the lab but comes unstuck on technical trails

The Callis is a performance-focused carbon gravel bike from new German brand, Avona.

While it appears to be ‘just’ another black, carbon, aero-optimised German bike, Avona’s attention to detail and spec customisation options make the Callis stand out from the crowd.

However, while it proved a fine match for the dry Tuscan roads and Strade Bianche-style gravel trails I rode it on, I have reservations about how it would handle British gravel in its stock guise.

A limited size range may also make it difficult for riders to find an optimal fit.

My test bike, with Shimano GRX Di2 RX825, costs €5,999.

Avona Callis GRX 2x12 Di2 frameset

As reported in our coverage of Avona’s launch, the Callis has been developed by former ARC8, BMC and Santa Cruz bike designer, Jonas Müller.

Avona pitches the Callis as a gravel race bike, with a classic mix of aerodynamically optimised tube shapes up-front, along with a skinnier rear end designed to improve comfort.

Tyre clearance is rated to a healthy 45mm with a front derailleur, or 50mm with a 1x drivetrain. That’s more than enough for most dedicated gravel bike tyres, although if you have your heart set on running 2.2in cross-country MTB tyres (like Dylan Johnson), that’s unlikely to work.

There’s also a down tube storage hatch for stashing spares and tools in a more aerodynamic fashion.

The claimed frame weight sits at a competitive 950 to 1,020g, depending on the frame size you opt for, although selecting a paintjob other than ‘clear coat on carbon’ will increase that slightly.

All things considered, it’s a smart-looking frameset, with clean lines and no quirks.

It’s fair to say the black finish and subtle branding, although undoubtedly lightweight, borders on dull.

Thankfully, Avona offers a more colourful, 'rosé / blue' finish, plus the option to get a super-jazzy, limited-edition paintjob from @savethepostalservice.

Avona Callis GRX 2x12 Di2 geometry

The Avona Callis is only available in four sizes, from S to XL.

My size L test bike featured 593mm of stack and 388mm of reach, with a steep, 73.5-degree seat tube angle and a slack 71-degree head tube angle.

In comparison, the Canyon Grail CFR (which is available in seven sizes) has a similar 591mm of stack but 411mm of reach in a size medium.

Paired with a zero-offset seatpost, the Callis felt relatively short and tall, then.

Bike fit is a personal thing, of course, so this isn’t necessarily a negative in and of itself. It’s likewise fair to say I’ve spoken to professional bike fitters who feel many modern race bikes have too much reach for the average rider, so it could even be a good thing for some.

The limited size range may, however, make finding exactly the right frame size trickier than with other brands, because there simply aren’t as many options available.

Avona goes some way to alleviating this by offering spec customisations at the point of purchase, but there’s only so much you can do to make up for a poorly fitting frame, so it’s not ideal.

Avona Callis GRX 2x12 Di2 specification

While the frame has been optimised heavily, Avona says the bulk of the performance gains comes from its spec choices.

While it wasn’t an option for me, Avona says riders will be able to customise its bikes at the point of purchase, to get the handlebar width, stem length, crank length and gearing they prefer.

Riders will also be able to choose spec upgrades at extra cost too, if desired.

My test rig was a stock spec with Shimano’s latest 2x GRX Di2 RX825 groupset, sporting 48/31t chainrings up-front and an 11-34t cassette at the back.

Avona also ships every Callis with a CeramicSpeed UFO waxed chain, for smooth and clean running – music to my ears.

The wheels and finishing kit come courtesy of Faserwerk, a component brand also created by Müller in 2019.

It’s all impressive, high-end carbon stuff, although – like the frameset – its subtle branding is extremely understated.

The ace up Avona’s sleeve is the Hutchinson Caracal Race TLR 40, though. At launch, the French brand claimed it was “the fastest gravel tyre on the market”, and independent testing by the likes of bicyclerollingresistance.com appears to back that up.

A man after my own heart, Müller says he came across this tyre while browsing bicyclerollingresistance.com and was blown away by the fact that – in the lab at least – it’s even faster than many road bike tyres.

The build is finished off by a Repente Quasar short-nose saddle.

Avona Callis GRX 2x12 Di2 ride impressions

I tested the Avona Callis while at Bike Connection’s Spring 2025 road and gravel event, in Massa Marittima, Italy.

The route was a hilly, 26km loop, with around half the ride on tarmac roads and the other half on a variety of gravel trails.

On the road, the Callis felt sprightly, with the efficiency of the Hutchinson tyres immediately obvious.

The riding position on my size L test bike was fairly short and upright, meaning you inevitably catch a bit more wind than on a longer bike, which encourages you to get low and stretched-out.

Although this feels less efficient on the road compared to a pure road-racing bike such as the Canyon Ultimate CFR (which I rode on the same trip), it feels better off-road. On steep gravel climbs, for example, the more upright riding position encourages balanced weight distribution and effective power production.

While it’s fair to say I’m relatively new to the world of gravel riding, one thing I’ve learned quickly is how critical tyres are – and there’s more to how gravel tyres perform than can be learned in a lab.

The Hutchinson tyres, in this case, feel fantastic on tarmac, broken roads and lighter, less technical trails, but they quickly reach their limit on anything tougher.

The slick central section and low-profile shoulder knobs simply don’t bite when things get loose.

Steep, rocky descents felt a little uncontrolled, while it was also fairly easy to induce rear-tyre slip when climbing out of the saddle on steep pitches.

My experience of using Hutchinson’s Caracal tyres (which feature the same tread pattern as the Caracal Race, paired with a tougher casing) in the UK also proves the tread pattern is almost useless when things get wet and/or muddy.

It’s fair to say those aren’t the conditions the Caracal Race tyres are designed for, and there’s no such thing as the perfect gravel tyre, but having the fastest tyres on paper is pointless if they don’t have enough grip for wherever you’re riding.

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Avona Callis GRX 2x12 Di2 bottom line

While I only had a short time on the Avona Callis, I came away with broadly positive first impressions.

Although they’re not the tyres I’d pick for general gravel riding in the UK, the Hutchinson tyres are rapid on favourable terrain and Avona’s philosophy of finding untapped performance gains in the details of the bike’s build is one I fully support.

However, the idea of mixing almost slick tyres and other marginal gains with a frame geometry that’s fairly short and upright feels slightly more of a contradiction – the build says 'race' but the riding position less so.

Avona’s extensive customisation options would enable me to fine-tune this to an extent, of course, but there are limits to how much you can change the fit of a frame without compromising other aspects of how a bike performs.

This wouldn’t be such an issue if there were more sizes, because you could more easily balance frame and component sizes to reach your ideal fit.

As it is, though, the limited size range could be a sticking point compared to competitor bikes for many riders.