When you get into a van with an Englishman, five Irishmen and a Scotsman, you know someone is going to end up looking silly. For the next few days, my aim is for it not to be me. The van is taking us from busy Málaga to remote Andalucía for four days of gravel biking, something I have never done and for which I am not sure I am cut out.

Most of my cycling experience is limited to a flat five-mile commute through London, or long-distance road touring holidays. I love sailing across smooth asphalt, and have always been slightly snobby about the rough stuff. Why bump along when you can glide?

My trepidation levels rise further when it becomes clear my companions are all veteran gravel and mountain bikers who have been training for this tour. They are mostly medical professionals – doctors, dentists and physiotherapists – which will be good news if something goes wrong, but also means they are all fitter than I am. I can see I have bitten off more than I can chew.

We are deposited on the northern edge of the Sierra Nevada mountain range, where our tour guides, Tim and Jenny, greet us with beers and booklets showing what’s in store. The headline figures: about 60km a day with a daunting 1,400 metres of climbing and descending.

The bike I’m borrowing is much lighter than my own, with tyres twice the width, and drop handlebars splayed out to the sides for extra control. The gearing goes much lower than I am used to, meaning even the steepest slopes should be – eventually – surmountable.

The next morning we ride out north towards the Sierra de Baza national park on what my companions refer to as “champagne gravel” – essentially a firm, flat road with a scattering of small stones across it. We breeze across the arid terrain, and past the derelict film set that played the town of Flagstone in Once Upon a Time in the West. The dramatic empty landscape has drawn countless location scouts to the area, and has appeared in Sergio Leone’s Dollars trilogy, Dr Zhivago and a KLF music video.

As we begin to climb through almond groves and into the first proper mountains of the week, the group strings out, with Tim leading the keenest and fastest at the front, and Jenny on an ebike with the stragglers – including me – to make sure nobody gets lost. We regroup every time there’s an unsigned turn, and to refuel with muesli bars and dried fruit.

As we climb, Jenny and the others offer me advice before my first ever gravel descent: hands on the drops so they don’t get knocked off if I hit a bump; weight as far back as possible; heels angled down on my pedals and hips balanced just above the saddle; don’t ride too close to the person in front; use both brakes at the same time; don’t look at the views in case I miss a turn; remember to breathe. It turns out there are a lot of ways to lose control.

Although I am nobody’s idea of fast, I make it down in one piece, but by the time we reach our next hotel, I am sore in muscles I didn’t know I had.

It is notable how empty this part of Spain is; the only cars we saw were when we stopped for a coffee in Gor, one of the main villages visited in the notoriously brutal annual 800km Badlands gravel race. But unlike the teeming beach towns on the Costa del Sol that have seen anti-tourist protests, this quiet part of Andalucía is desperately trying to attract more people, and we feel very welcome. One sign reads: “¡Macrogranjas no, turismo sí!“ (“Megafarms no, tourism yes!”)

Day two is even quieter, with not a single car seen all day. This is just as well, as the day starts with a climb of 1,000 metres up El Chullo, the tallest peak in the Almería region. We wind along a single track path past piles of rocks and holes dug by rootling wild boar before stopping near the summit for a lunch of ham and cheese bocadillos. Today’s descent is easier, and I begin to relax, watching the other riders to follow their lines, although I still find myself forgetting to breathe because I am concentrating so hard.

Day three also begins with a 1,000-metre climb, with glorious views unfolding as we make our way round switchback after switchback and up past the treeline to a plateau. I am beginning to relax – I could do this every day. But what I haven’t banked on is the descent on bone-shuddering roads so bumpy they drew complaints from the professionals in the 2023 World Gravel Series. By the end of the day, my wrists ache. One of my doctor companions tells me it’s because I’m still too tense, but I don’t think I was the only one quietly relieved to hit the asphalt road back to the hotel.

Our final day turns out to be the most dramatic. We ride along dry ramblas, or riverbeds, which provide a new challenge with jungle-like foliage hanging above us and muddy stretches that feel like riding through porridge.

The clouds, which have been menacing us all day, suddenly break and start to soak us. As we grind our way up through the mud, we suddenly see water come round a corner upstream. As the trickle turns into a gush and spreads across the riverbed, turning the porridge to soup, we keep riding. My wheels spin in the sand at points, but I have learned to keep pedalling through it and use my balance to stay upright, rather than to brake or turn.

Tim takes charge and marshals us, giving directions by radio and guiding people uphill until everyone is safely out of the way of the rising waters, and one soggy climb later we are greeted at our final hotel by Jenny with a van full of cava. As we drink, one of the Irish doctors jokes: “Was this what you signed up for?”

I look down at my drenched shoes, filthy bike and sore hands. My face is caked with mud. I have ended up looking silly, but it doesn’t matter. I can see that my snobbery about gravel biking was stupid – I have ridden routes a road bike could never have handled, and had adventures that would never have happened on asphalt. There were plenty of literal bumps in the road on the way to my gravel conversion, but it turns out they’re part of the appeal. Why glide along when the bumps are so fun?

The five-night Sierra Nevada gravel bike tour was provided by Pure Mountains, which provides self-guided tours from £870pp and guided tours from £1,090pp