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Bike – Balmberg: the steepest pass road in Switzerland

    Balmberg Pass steep bike

    Photo: At the base of the north side.

    A fairly obscure low pass that has one of the most memorable ascents/descents in Switzerland.

    The north side of the pass is what makes this stand out. The midsection isn’t composed of hairpins so much as it is a corkscrew – going down especially feels like being in the asphalt version of a glacier mill. If that wasn’t enough it is also home to one of the few herds of Bison in Europe.

    The Balmberg pass

    Balmberg is a pass near Solothurn connecting the villages of Günsberg and Welschenrohr. It doesn’t get much notice being hidden behind the higher and more imposing Weissenstein. Plus topping out at a mere 1079m the pass isn’t very high even by the standards of the lower lying Jura, nevermind the Alps. It does at least have a sign at the top and the Postbus has to honk its horn on the winding road.

    It is obscure enough that there is only one cycling video going up the south side and a few motorbikes filming themselves going over the whole thing. The Tour de Suisse did go up the Balmberg in 1981, but only a time trail up the south side. As far as I can tell no professional race has faced the north side – a tour stage ending with a climb up the equally challenging south side of Weissenstein and then the north side of Balmberg would be a very memorable event.

    What it lacks in size it makes up for in gradient. The north side of the Balmberg pass is often listed as the steepest pass road in Switzerland at 25% (with the steepest average gradient too). The climb from Welschenrohr in the valley up to the pass only gains 365m of elevation, but it is squeezed into 2.5km with gradients of up to 25% and an average gradient of 17% over the steepest 1.7km.

    There are steeper roads in Switzerland (Griesalp famously hits 28%) but this is the steepest pass road which is open to the public.

    Balmberg pass map
    Location of the Balmberg Pass.

    Practical information:

    • Height profiles at
    • Traffic is rarely heavy. The road is fairly narrow (1-1.5 lanes) and windy so drivers are generally going slowly and carefully. It is a popular touring option at weekends and people will be driving up to the car park, so a weekday visit is nicer if possible.
    • Watch out for the Postbus. There are 6-7 buses a day in each direction between Solothurn and the hotel just below the top of the pass which run every 2 hours or so. Having one behind you on a narrow section with nowhere to get out of the way is a bit awkward.
    • The road south side is kept open year round (it even has the exotic novelty of being a ski resort you can cycle to). The other roads going off it are at the mercy of the climate – the path to Weissenstein especially is deep in the shade and will remain snowy/icy long after the rest of the area is rideable.

    North side from Welschenrohr (3 km +395m)

    From Welschenrohr there is a slight drop to the valley floor, a gentle climb across it, then you reach the pass sign and the pain begins. The actual 25% section is very short, but the rest of the climb makes up for it. The first 500m past the sign and as it loops around a farm are only 8%, then it turns into the forest and the next 1.7km is an unrelenting 17% climb until it mellows out for the last few metres of climb after the final hairpin.

    The road twists and turns like something out of a video game so there is never a depressing moment of seeing an endless wall rising up ahead. There is also a nice bit of variation with a mix of forest and open meadow. The curves are so tight that every so often a truck driver who ignores the warning signs will find themselves stuck.

    A gate part way up leads to the Bison of the Wisent Thal project. These could be in view of the pass road, but more likely they won’t be so you will need to head off on foot or with a MTB to have a chance of finding them (ideally without coming up on them too quickly).

    South side from Günsberg (4.5 km +429m)

    This is the much more common way to reach the pass and a very popular climb for cyclists in the area (not least because far more people live on the south side). This has a much gentler gradient than the north side, but is still a respectable 10%.

    The pass road starts from Günsberg which is itself 200m above the valley floor. There are 4 paved ways to reach it which will mostly depend on where you are coming from (all of which involve some steep climbing):

    • Up the Solothurnstrasse. The ‘main’ road from the valley. Direct but with the most traffic.
    • Via Hubersdorf and Niederwil. Detouring off from the main road into Günsberg this is much quieter traffic-wise than the Solothurnstrasse but is even steeper (hitting 15% on the outskirts of Günsberg).
    • Via Rüttenen and Balm. Climbing up from Solothurn, through Rüttenen, and traversing along the foot of Weissenstein. This offers expansive views around Balm and is my favourite way.
    • Via Kammersrohr. The steepest and most roundabout route, but with next to no traffic and some fantastic views.

    From Günsberg the road enters the forest and stays in the trees whilst hugging the steep side of the valley most of the way up, before finally entering open meadow for the last few km which even turns into hairpins for the final climb. The gradient remains fairly constant at around 10% the whole way – though I swear the first 2 km out of Günsberg are the worst.

    The most unique sight on this side is the numerous ‘no roller-skating’ signs on the way down. Something that no other mountain road in Switzerland has, but apparently it happened enough that they had to take action.

    Another point of note are the little geology information tablets in rather awkward places. One is placed next to a blind corner on a very narrow section of road – which is one way to make reading about fossils more interesting.

    Balmberg no skating
    The (gentler) south side has a number of these signs.

    An alternate route is the Alte Balmbergstrasse which connects Balm to near the top of the pass and was the only way up until the mid 1940s. This is a beautiful car-free road through meadow and forest – it is however also an unrelenting brutal 17% climb on loose gravel which just powers straight up the valley floor. Even coming down it on a mountain bike requires constant braking and careful positioning. As a warning to not blindly trusting automatic route planners asking Google maps to direct you from Günsberg to Balmberg will send you up here. The Ruine Balm and the hidden waterfall which is one of my favourite spots around Solothurn are at the base of the climb, so even a failed attempt has a nice payoff. I became rather obsessed with this after too long locked up in home-office over winter one year and made it my goal in 2021 to beat it.

    What to do at the top

    The pass itself doesn’t have much of a view: just the meadow towards Röti and trees (and a car park). It is at least high enough to have a pass sign to pose next to.

    With a road bike there isn’t anything to do but follow the pass road one way or the other. Having a drink at the hotel or restaurants near the top would be the best option.

    Another option for a view with a road bike from the south is skipping Balmberg and instead going up from Wiedlisbach via Rumisberg and Farnen to the lookout at Bättlerchuchi (8.3km, +600m) which sits at an almost identical height to Balmberg but has wide open views.

    With a MTB or at least reasonably rugged gravel/touring bike the options along the ridge open up (be aware that the paths around the pass can be busy with hikers at the weekend). At least carry on past the rope park to the bench with a view. Carrying on to Stierenberg is even better. And now the suspension bridge is opened it is possible to carry on further to Schmiedenmatt.

    Balmberg pass cycling
    At the pass with most of the view blocked by trees (high enough for a sign at least).
    Balmberg pass mountain bike
    Heading towards Stierenberg with the Alps in the background.

    Cycling Routes:


    Solothurn – Balm – Balmberg – Kammersrohr – Solothurn (29km, +/- 670m).

    Up to Balmberg and then sweeping round to Kammersrohr for more views on the way down.

    Solothurn – Balmberg – Welschenrohr – Weissenstein – Solothurn (36km, +/-1280m).

    The easy way to hit the passes, though watch out for the last section on the north side of the Weissenstein pass when the 10% grade bumps up to 15% for most of the last km.

    Solothurn – Balmberg – Welschenrohr – Schmiedenmatt – Rumisberg Solothurn (44km, +/- 1230m).


    Solothurn – Balmberg – Weissenstein (optional Röti) – Solothurn ().

    The road from Balmberg towards Weissenstein starts nice and gently over the flat meadow, then turns into a steep and rocky challenge. Detouring up to Röti adds another 127m of climb with some steep and slippery sections, but is more than worth it for what is arguably the best view in the region.

    Mountain bike Röti Weissenstein
    Röti to myself on a weekday evening.

    Solothurn – Balmberg – Stierenberg – Further along the ridge

    After passing Stierenberg there are various routes to carry on along the ridge or drop down on road or single trail.

    One option is to pass by Teuffelen and grab some of their home-made cheese on what I call the Solothurn Cheese Run

    Solothurn – Balmberg – Through the Bison zone – Schmiedenmatt – Solothurn ().

    It isn’t guaranteed that you will see the bison (I have a 33% success rate). If you do remember these are not docile cows – follow the warning signs at the entrance and keep your distance

    The Double Balmberg. Route: Solothurn – Balm – Balmberg (via the old road) – Welschenrohr – Balmberg (via the paved north side) – Solothurn (29km, +/-1210m).

    Up the old street, down to Welschenrohr, then back up the steep north side.

    The Double Bastard. Route: Solothurn – Oberdorf – Weissenstein – Welschenrohr – Balmberg – Rüttenen – Solothurn (36km, +/-1320m).

    Up and over Weissenstein pass (south to north), then up and over the Balmberg pass (north to south). Two of the steepest pass roads in Switzerland back to back.

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