Best climbs in the Austrian Alps

Simon Warren riding in the Austrian Alps — (Image credit: Future / Richard Butcher)

One of the very first things I was taught as a young cyclist in the 1980s was to spin, not push. It's still true: pushing too big a gear is less efficient and more quickly tires the leg muscles. Back then, though, we were too full of machismo to ride anything lower than a 21-tooth sprocket on the back. Over the years, I have let my manliness be chipped away as my cassette's biggest sprocket has gained cogs, from 21 to 25 to 29. But never did I imagine I'd fit a 32 - until now, driven to extreme measures by the mountains of Austria.

My first encounter with Austrian climbs was in 2023 when, over an intense couple of days, I ticked off famous roads including the Kitzbüheler Horn and the giant Grossglockner. They were so unrelentingly steep they almost broke me. Whereas most Alpine climbs have average gradients of 6-8%, these Austrian roads rarely drop below 10%. My 34x29 simply wasn't low enough. I made a mental note: if ever you return, go lower.

Fast-forward to 2025, and I was once again heading to Austria, specifically to the country's southernmost state, Carinthia, in the Eastern Alps. I'd read about a trio of climbs so fearsome they were rarely attempted on anything higher-geared than a mountain bike.

Only a few hundred attempts had been recorded on each Strava segment, and the roads are closed to cars so don't even appear on Google Street View. Even so, they are fully surfaced roads, each one leading to a high-altitude reservoir from which they take their names, the Oscheniksee, the Hochwurtenspeicher and the Großsee.

Simon Warren

Author of the popular 100 Climbs books, Simon Warren is one of the leading experts on cycling climbs. At the end of the season he can be found at the side of a steep climb, with his sign, cheering on hill climbers

A Triple challenge in the Austrian Alps

I worked out that I could plot a route tackling all three of these climbs in one big ride of 173km, racking up 5,590m of altitude. The plan almost didn't survive first contact with reality, when locals in Flattach, our base for the ride, informed us that the three climbs are closed to cars by locked gates.

CW's photographer Richard 'Butch' Butcher would only be able to join me if he was willing to ride. Our genius solution was to hire him an e-bike - and with that, our mission was back on. We couldn't collect the e-bike from Intersport until 9am, obliging us to make a leisurely start with a few extra visits to the breakfast buffet - we'd be grateful for those later.

Come 9.30am we were on the road, which almost immediately ramped up to 15%. We almost missed the turn-off to Oscheniksee - guarded by a small green metal bar, it's a tiny service road that heads off into the forest. Right away it was savage, and far rougher than I'd expected. Even with some air let out of my 26mm tyres, I was struggling for grip, especially on the sections where the gradient kicked up to north of 15%.

Then again, it would have been churlish to complain, since this was why I was here - to struggle. For the next 9km this climb averaged - yes, averaged - 13%. All I could do was engage the 32-tooth sprocket and fight gravity with all my might. On the densely forested lower slopes, switchbacks meander back and forth on the deteriorating surface. Every now and again I was treated to a smooth section of asphalt, but seconds later I was once again dodging potholes and spinning on loose gravel.

Don't get me wrong - it was rideable, just about, and certainly classifiable as a road climb. Heading onto the upper reaches, once clear of the view-limiting conifers, the scenery opened out and was jaw-dropping.

The apparently primordial path picked its way through the stunning, rugged beauty of the surrounding peaks on a gradient that - and this warrants repeating - rarely dropped below 15%. Once at the summit, there was only one word for it: wow. Everything I'd read was correct, what a truly fantastic road. Bring on the next two.

Mountain spectacular

After taking a few selfies, it was time for the descent, which - given all the potholes and gravel - wasn't much faster than the ascent. About halfway down, my inadequately inflated rear tyre hit a ridge and went bang. Never mind, I popped in a new tube, and got going again. A kilometre later, more hissing - another puncture.

Thankfully Butch was able to whiz back to the car on the e-bike to pick up another tube. With the second repair done, we were on the move again. Now monstrously behind schedule, we wasted no time tackling our second climb of the day, Hochwurtenspeicher.

It begins from the same road we started on, seven kilometres down in the valley, and for a while it's nice and smooth. This abruptly changes once you reach the ski lifts and the gate that prohibits car access. A flurry of hairpins followed, at a ridiculous gradient, before the road disappeared into the dank gloom of a tunnel.

This climb differs from the Oscheniksee in that it doesn't dish out its suffering in one continuous, unrelenting stretch. Instead, its steepest gradients are broken up with the odd tunnel, a couple of descents and, on the day of our ride, a pause for marauding cattle.

Kilometre after kilometre of mountain drama, the climb takes you past the glittering artificial lakes of Wurtenspeicher, Stübelesee and Weißsee, as well as a spectacular gallery tunnel with ice cold glacial water cascading over its edge. The climb ends at the Hochwurten reservoir, in the shadow of the Molltaler glacier, and the last few kilometres were without doubt some of the most spectacular I've ridden.

Once at the summit, in the centre of the most amazing mountain amphitheatre, it was time to take stock. I'd been on the road since 9.30am and it was now 2pm. So far I had covered just 41km, yet climbed 3,092m - as much elevation as a long Tour de France stage. With no spare tubes left, and still seriously behind schedule, we made a tough decision. If we were going to get the e-bike back to the shop on time and make it to the final climb, I'd have to jump in the car. Ah well, as much as I hated having to ditch the original plan, at least 3,092m in 41km was going to look impressive on Strava.

"One thing was certain: I wasn't leaving Austria without conquering that climb."

Back at Intersport, we picked up a couple more tubes and dropped off the e-bike. We were going to have to hope the final gate was unlocked and that Butch would be able to get through in the car. Crestfallen that my original plan had been abandoned, I now tried to focus on the positive: one more mind-blowing ascent lay ahead. Unloading the bike in Döllach, the temperature was now over 30°C as I set off on the road to Großsee.

The first section wound its way through postcard-perfect farmland dotted with timber chalets. Eight kilometres in, I reached the gate. Damn, it was locked. Fate, it seemed, was against us. Without an e-bike there was no way for Butch to follow and take photos, and without him there was little point pressing on. My mojo was lost in the forest, and reluctantly I turned back, rolling down to base to hatch a new plan. One thing was certain: I wasn't leaving Austria without conquering that climb.

KEY INFORMATION

How to get there: We flew with Ryanair from London Stansted to Klagenfurt airport (from about 200 return), from where it's a 90-minute drive to Flattach. Klagenfurt is a tiny airport but with numerous car hire options.

Where to stay: We stayed in the north of Carinthia, in Flattach, at the Hotel Flattacherhof (from 125 per person per night; flattacherhof.at) which was perfect and bike-friendly. The breakfast buffet was plentiful, dinner exceptional, and the helpful staff even packed sandwiches from the breakfast buffet for our lunch!

When to go: This is high mountain country, so the weather can change in an instant from 30°C heat to torrential rain. For best conditions and to ensure the snow has melted, travel between June and September.

What to bring: You'll be fine on a road bike but for the rougher climbs I recommend tougher tyres. As for gearing, the lower the better. I used a 34x32 and it was borderline adequate. There are many unlit tunnels, so remember to take lights.

The next day, being Sunday, brought a fresh complication: Intersport was shut, so the e-bike was out of the question. Butch showed little enthusiasm for a six kilometre hike to the summit, leaving one option - I'd have to ride up alone, camera and tripod on my back, relying on the self-timer.

We set off early and, from the gate that had thwarted us the day before, I pedalled away into the forest. The surface was rough at first and I braced for more bad luck, but within a few hundred metres it smoothed out. Unlike the previous two climbs, this one was in excellent condition for a 15% mountain road topping out at 2,300m.

Just as on the previous two ascents, the drama of the surroundings, the remoteness, and the ruggedness of the road were sublime - a true mountain paradise. And the entire way was, again, an almost laughable gradient.

Unlike on those earlier climbs, on this one I had company - midway up I was passed, effortlessly, by two whirring e-MTBs. Heaving and hauling my way behind them, I eventually reached the summit on top of the towering dam wall and took in the amazing view.

Although my dream of riding all three in one ride wasn't realised, these three sensational roads are up there with the greatest I have ever ridden. They are beyond beautiful, and they test the body and mind in ways rarely experienced on the better-known European mountains.

Far from the madding crowds of the Passo Dello Stelvio, in the Italian Alps, or the Col du Galibier, in the French Alps, southern Austria's Alps are quieter than France, prettier than Spain, cheaper than Switzerland and honestly the best place to ride if you, like me, love nothing more than hammering your legs on savage gradients.

1 Oscheniksee
Strava segment
Length: 8.77km
Height gain: 1,161m
Summit height: 2,394m
Average gradient: 13.2%
Rated the third-toughest climb over 2,000m in the Alps. As rugged as hell and relentlessly steep with kilometre after kilometre of 15% slope, you literally have to fight your bike upwards the whole way.

2 Hochwurtenspeicher
Strava segment
Height gain: 1,268m
Length: 14.09km
Summit height: 2,420m
Average gradient: 8.1%
A never-ending road of intense beauty and drama. The savage gradients just keep coming, broken up by tunnels, hidden lakes, breathtaking views and a summit set in a scene of pure wonder.

3 Großsee
Strava segment
Length: 16.08km
Height gain: 1,429m
Summit height: 2,378m
Average gradient: 8.6%
Another of Carinthia's wild wonders, packed with stretches of 12-15%. Beyond the gate at halfway, the real beauty arrives, and from here it's a car-free, well surfaced, spectacular journey to the reservoir at the summit.

Simon has been riding for over 30 years and has a long connection with Cycling Weekly, he was once a designer on the magazine and has been a regular contributor for many years. Arguably, though, he is best known as the author of Cycling Climbs series of books. Staring with 100 Greatest Cycling Climbs in 2010, Simon has set out to chronicle and, of course, ride the toughest cycling climbs across the UK and Europe. Since that first book, he's added 11 more, as well Ride Britain which showcases 40 inspirational road cycling routes. Based in Sheffield, Yorkshire, Simon continues to keep riding his bike uphill and guides rides, hosts events and gives talks on climbing hills on bikes!