The Alps won’t wait: The Specialized Aethos 2 Pro is ready for mountain passes

​At the end of June, I’ll be taking part in the TOUR Transalp 3-Day Challenge – three stages through East Tyrol and the Dolomites, featuring mountain passes such as the Staller Sattel, the Passo Giau and the Passo Rolle. If you’d like to join in: Registration is still open.

Bike fitting first

Before you take a bike into the mountains, it needs to fit properly. Not just roughly, but perfectly. Especially in a multi-day race, where you’re in the saddle for three days running, every millimetre that’s out of place will take its toll.

I arrive 15 minutes earlier than agreed – and start by having a cappuccino with oat milk. Then I get into my cycling kit and head over to see Marcel Berger, a sports scientist and bike-fitting expert at Specialized in Munich.

The bike is already set up in the fitting room. Marcel doesn’t start fiddling with the bolts straight away, but begins by asking questions: my injury history, current problems, and my goals. Only once he has a clear picture of how I should be positioned on the bike does he move on. This is followed by a physical examination – during single-leg squats, for example, Marcel observes whether my knees cave in or splay out. There are also flexibility tests. All of this is taken into account later when adjusting the bike.

Then the cleats: check their position, adjust them. Insoles are customised to fit my feet, cut to size and placed in the shoes. I am then fitted with markers – for the Retül Motion Capture System, which records movement data whilst I’m cycling.

I set off. At first glance, the position looks roughly right, but there’s room for improvement: the saddle goes up a bit, and the offset and angle are adjusted. We try two more saddles – and end up back with the original one, the Power Pro Mirror, which I already use on my gravel bike.

If the Aethos were my own bike, we would have swapped the handlebars as well: it’s fitted with 380-millimetre handlebars, but 360 would suit me better. The height of the cockpit is just right, but the brake and gear levers still need to be turned inwards slightly.

After about 2.5 hours, the moment has arrived: the bike is just right. Now it’s just down to my legs to deliver.

Why this bike for the mountains?

The Aethos 2 is a lightweight road bike, not strictly a climbing bike – but in practice, it amounts to the same thing. The frame of the S-Works version is said to weigh just 595 grams, currently the lightest production frame in the world. The Pro version, which I ride, is slightly heavier – the complete bike comes in at around 6.7 kilograms – but the handling characteristics are the same: lively, precise and surprisingly comfortable for such a light bike.

The cockpit is said to offer around 30 per cent better shock absorption than the aerodynamic Rapide cockpit on the Tarmac. In the test lab, the S-Works Aethos 2 performs remarkably well in terms of front-end comfort – firm but not hard, both in the saddle and on the handlebars. This is a real advantage on Alpine passes, which aren’t always in perfect condition. For even greater comfort, the Aethos 2 has 35-millimetre tyre clearance – it comes fitted with 28er tyres.

A vulnerability

To be honest, there is one weak point: the gear ratio. My cassette goes up to 33 teeth; the small front chainring is a 35. That’s perfectly adequate for flat to hilly terrain – but for four mountain passes in a single day in the Dolomites, it’s a bit of a stretch. The gear ratio is, however, set lighter than on the S-Works Aethos 2 with Shimano Dura-Ace; it comes with a 52/36-tooth crankset and a 10–30 cassette.

I’m still thinking about whether to adjust the gearing for the mountains. And I might also change my tyres – from my usual gravel tyres to 30-millimetre ones, as even Alpine passes aren’t always perfectly smooth tarmac. If you’re considering the Aethos 2 for similar rides, both points are worth bearing in mind.

It was already clear when I picked it up in Munich – and during the fitting beforehand – that this is a bike you understand the moment you sit on it. Not through numbers, but through the feel of it.

​In eight weeks’ time at the latest, we’ll know whether it’s made for the Alps. Until then, I’m off on holiday – a gravel bikepacking tour awaits.