The Stelvio from Bormio is the kind of climb that distorts your sense of time. Twenty-four kilometres at 7.1% average, 48 hairpins scratched into the mountainside, and a summit at 2,758 metres — the highest paved pass in the Eastern Alps. The Granfondo Stelvio Santini wraps roughly 151km around it, with approximately 4,000m of climbing across the day, but the event is defined by its final act: that wall of switchbacks climbing into thinning air while the temperature drops a degree every few hundred metres of altitude.
The riders who finish well — still making power through the final hairpins, arriving at the summit with enough presence to appreciate the view — are the ones who spent four months building climbing endurance, who paced the early route like adults, and who understood that 2,758m of altitude changes the rules. The riders who crack are the ones who treated it like a long sportive instead of a high-altitude climbing event.
This guide follows the same framework we use with riders inside Not Done Yet who are targeting the Stelvio, the Marmotte, the Otztaler, and comparable Alpine events. The numbers are based on real finisher data, the training is specific to the demands of sustained high-altitude climbing, and the pacing plan accounts for what actually happens to amateur power output above 2,000 metres.
What Makes the Granfondo Stelvio Different
Three things separate the Stelvio from other major Alpine granfondos — and all three compound on each other.
The altitude. At 2,758m, the Stelvio summit is higher than anything on the Marmotte (Galibier, 2,642m), higher than the Otztaler (Timmelsjoch, 2,509m), and higher than every other paved pass used by a major granfondo in the Eastern Alps. At that altitude, air pressure drops to roughly 73% of sea level. Most amateurs lose 20-25% of their sustainable power above 2,200m. The effort that felt steady at 1,500m feels desperate at 2,500m — not because the gradient changed but because the oxygen supply did.
The steepest section lands mid-climb. The Stelvio from Bormio is not evenly graded. The first 7km are relatively manageable at 6-7%. Then between km 8 and km 14, the gradient ramps to sustained sections above 10%, with pitches hitting 14%. This is the trap. Fresh riders handle those gradients. Riders at km 8 of a 24km climb, having already completed the earlier route with its own climbing, do not handle them the same way — and riders who go too hard through that section arrive at the exposed upper slopes above 2,200m with their legs already spent and their oxygen delivery declining.
The descent. Most granfondos finish in a valley or on a plateau. The Stelvio finishes at 2,758m, and the 48 hairpins that got you up are the same 48 hairpins that get you down. That is 24km of technical descending on tired legs, in temperatures that may be 5-10°C, with hands that have been gripping bars for six hours or more. The Stelvio descent is not a rest. It is the most dangerous section of the day.
The temperature gradient. Bormio sits at roughly 1,225m. In early June, the valley is 25-30°C. The summit can be 5-10°C — a swing of 20°C or more across 24km of climbing. Riders who leave Bormio in a jersey and shorts, without layers in their pockets, arrive at the summit shivering and face a 48-hairpin descent in conditions where wind chill pushes the effective temperature well below freezing on exposed skin.
Fitness Benchmarks: Where Do You Need to Be?
Your power-to-weight ratio is the strongest predictor of how the Stelvio will go. These benchmarks are based on finisher profiles and assume disciplined pacing and consistent fuelling.
| Target | W/kg (sustained climbing) | Approximate Stelvio Time | Notes | |--------|--------------------------|-------------------------|-------| | Competitive | 4.0+ W/kg | ~75-85 min | Strong climber, altitude-adapted, dialled nutrition | | Strong finish | 3.4-3.9 W/kg | ~90-110 min | Solid amateur, steady pacing, no errors on the steep section | | Comfortable finish | 2.8-3.3 W/kg | ~120-150 min | Adequate fitness, pacing and fuelling matter more than power | | Completion | 2.4-2.7 W/kg | ~160-180 min | Conservative effort, full use of feed zones, gearing critical |
Two caveats matter. First, these are sustained climbing watts at altitude — not your 20-minute FTP test result from a turbo session at sea level. Your FTP might read 3.5 W/kg at home, but at 2,500m on the Stelvio, after four or five hours of riding, your real output will be closer to 70-80% of that number. The FTP zones tool frames your training intensities, the Climbing Time Estimator translates your W/kg into projected ascent time, and the Race Predictor models your full-event finish window — but apply a 20-25% altitude discount to any estimate for the upper Stelvio.
Second, pacing shifts these brackets significantly. A 3.2 W/kg rider who paces the steep section conservatively and fuels from kilometre one can finish faster than a 3.6 W/kg rider who attacked the 12% pitches at km 10 and cracked at km 18.
The 16-Week Training Structure
The plan follows a base-build-taper architecture. It assumes you are already riding 8-10 hours per week with some climbing experience. If you are starting from a lower base, add 4-6 weeks of aerobic foundation before beginning week one.
Phase 1: Base (Weeks 1-6)
Volume: 8-11 hours/week. Four to five rides. 80% in Zone 2.
The goal is aerobic capacity, saddle time, and the early development of climbing-specific endurance. Dan Lorang's athletes at Red Bull-Bora-Hansgrohe build enormous aerobic blocks before Grand Tours. The principle scales directly: your easy riding must be properly easy. If you cannot hold a conversation, it is not Zone 2.
Weekly structure:
- 3-4 Zone 2 rides (1-2 hours midweek, building the weekend long ride progressively)
- 1 quality session: tempo or sweet spot, 2x20 minutes at 88-93% FTP
- 1 long ride building from 3 hours to 4.5 hours, with 600-1,200m of climbing
- 1-2 gym sessions: single-leg press, lunges, core work, hip stability — posterior chain support for climbing posture without excessive joint load
Key metric: By week 6, your long ride should be 4.5 hours with sustained climbing at conversational pace. If that feels like a race rather than a training ride, stay in base longer before moving to the build phase.
Phase 2: Build (Weeks 7-12)
Volume: 10-14 hours/week. The climbing-specific work begins in earnest.
This is where the training starts to look like the event. Two quality sessions per week, long rides building to 5-6 hours with significant vertical gain, and at least two weekends where you stack back-to-back climbing days.
Weekly structure:
- 2 quality sessions (see below)
- 2-3 Zone 2 rides
- 1 long ride building to 5-6 hours with 1,500-2,500m of climbing
- 1 gym session (reduced from base — maintain strength, do not build it)
Quality session 1 — threshold climbing: 3x15 minutes at 92-97% FTP on a real gradient (6-8%), progressing to 2x20 minutes by week 11. Recover for 5-7 minutes between efforts. This is the session that builds the sustained power you need for 24km of Stelvio. The gradients between km 8 and km 14 demand a threshold effort even at conservative pacing — your body needs to hold that output without spiking above it.
Quality session 2 — VO2max intervals: 5x4 minutes at 106-115% FTP with 4 minutes recovery. Professor Seiler's research is clear — two intensity sessions per week in a polarised framework, separated by enough recovery to execute them properly. The VO2max work raises the aerobic ceiling that makes your threshold efforts more sustainable, and at altitude that ceiling matters more because the air is doing less of the work for you.
The stacked weekend: At least twice in the build phase, ride a 4-5 hour Saturday with 1,500m+ of climbing followed by a 3-4 hour Sunday with 1,000m+ of climbing. This teaches the body to recover overnight and produce power again on fatigued legs — the exact scenario you face when the Stelvio ramps up after hours of riding.
Low-cadence torque work: One session every two weeks, incorporate 3-4 efforts of 6-8 minutes at 55-65 RPM on a moderate gradient (5-7%). These recruit type 2 fibres at aerobic intensities and build the neuromuscular capacity for grinding through the 12-14% pitches between km 8 and km 14 without your pedal stroke falling apart.
Phase 3: Taper (Weeks 13-16)
Weeks 13-14: Volume holds at 10-12 hours. One final stacked weekend, ideally on terrain with sustained 20-30 minute climbs. Reduce threshold work to maintenance — 2x12 minutes at FTP, nothing more.
Weeks 15-16: Volume drops 30-40% in week 15, 50% in week 16. Keep short sharp efforts (3x5 minutes at threshold, 4x90 seconds at VO2max) to keep the legs responsive without adding fatigue. The common mistake here is panic — riders feel fitness slipping and add volume in the final week. The taper does not build fitness. It sheds fatigue. A well-executed taper is worth 5-10 watts on race day. A botched one — training hard until Wednesday of race week — costs you those watts and more, and you feel it at km 18 on the Stelvio.
The Stelvio from Bormio: A Pacing Strategy
The Stelvio from Bormio is a 24.3km climb that demands a three-act pacing plan. Treat it as one effort and you will overcook the steep middle and pay for it in the thin air above 2,200m.
Km 1-7: The Opening (avg 6-7%)
Target effort: 75-80% FTP. The gradient is steady and manageable. Your legs may feel better than they should after hours of earlier riding — adrenaline and the sight of the first hairpins do that. Resist the pull. Your VAM through this section should be 15-20% below your peak sustainable climbing rate. The Stelvio's gradient will do the rest of the work for you later; spend nothing here that you do not need to spend.
Eat before you start climbing. A gel at the base and a full bottle going in. You will not feel like eating at km 16.
Km 8-14: The Steep Section (avg 10-12%, max 14%)
Target effort: 82-88% FTP, dropping as gradient spikes. This is the crux of the entire day. The gradient kicks up to sustained double-digit percentages with pitches hitting 14%. Here is where pacing discipline pays for itself or where the day falls apart.
On the inside line of each hairpin, the gradient steepens further — the apex of a hairpin at 10% average can hit 14-16% on the inside. Ride the outside of the hairpin where the gradient is 2-3% shallower and accept the extra 20 metres of road. The riders cutting hairpins on the inside to save distance are the riders whose cadence drops to 45 RPM and whose heart rate spikes above threshold. That spike at km 10 is still being paid for at km 20.
Stay seated as much as possible through this section. Standing attacks on steep gradients at this point in the day cost disproportionate energy. If you must stand, do it for 15-20 pedal strokes to relieve saddle pressure, then sit immediately.
Km 15-24.3: The High Altitude Section (avg 7%, altitude 2,200-2,758m)
Target effort: 78-85% FTP, accepting altitude-adjusted power. The gradient eases but the altitude takes over. Above 2,200m, your power will drop even if your effort stays constant. This is physiology, not weakness. At 2,500m, you have roughly 25% less oxygen available than at the start in Bormio. A pace that felt controlled at km 12 becomes properly hard at km 20, not because the road changed but because the air did.
Watch your heart rate through this section. If it is rising while your power drops, you are already above your sustainable ceiling at this altitude. Dial the effort back 5-10 watts immediately. The summit is not a sprint finish — it is the reward for getting there in one piece.
The final 3km to the summit are exposed, often windy, and cold. If you have not already put on your arm warmers and gilet, do it at km 21 — not at the summit, where your hands may be too cold to manage zips and pockets.
Gearing: Get This Right Early
Run a compact crankset (50/34) with a 34-tooth cassette as the baseline. Riders under 3.5 W/kg should run 34x34 — and there is no shame in it. The Stelvio from Bormio has sustained pitches above 12% and you will be climbing them after hours of accumulated fatigue at altitude.
Here is the practical maths. A 75kg rider (plus 8kg of bike and gear) climbing a 12% gradient at 34x28 needs roughly 300 watts to maintain 70 RPM. At 34x34, the same cadence needs roughly 245 watts. After five hours of riding, at 2,300m altitude where your power is already down 15-20%, those 55 watts are the difference between climbing and walking.
The hairpin factor makes gearing even more critical. The inside line of a hairpin on a 10% gradient can hit 14-16%. If your easiest gear is 34x28, you are pushing a gear that demands threshold power to turn over at walking cadence — on a gradient that arrives every 500 metres for 24km. That is not racing. That is suffering with a solution already available.
Check and test your gearing early in the training block. Swap the cassette by week 8 at the latest so you train on what you race. Your legs need to adapt to the cadence and effort pattern of a 34x34 at 8-12% — it feels different from a 34x28, and different is fine as long as it is familiar by race day. Run the numbers through the Gear Ratio Calculator to see exactly what cadence and speed each combination gives you on the Stelvio's gradients.
Fuelling Strategy
The Granfondo Stelvio is a 6-9 hour day for most amateurs, with a significant portion of that time spent climbing at altitude. A 75kg rider finishing in 8 hours burns somewhere around 5,000-6,000 kcal. You cannot carry that much food. What you can do is close the gap enough that glycogen stores and fat oxidation cover the rest — and at altitude, where the body burns through glycogen faster, the margin for under-fuelling is smaller than it is in a valley sportive.
Target: 80-90g of carbohydrate per hour from kilometre one. Not from the base of the Stelvio. Not from when you feel hungry. From the start. Use the fuelling calculator to plan the exact quantities against your projected ride time.
The first two hours are your best fuelling window. Gut function is strongest when you feel strongest. By hour five, your ability to absorb carbohydrate diminishes — particularly at altitude, where reduced blood flow to the gut compounds the problem. Riders who eat aggressively in the first two hours are the riders still eating comfortably at km 18 on the Stelvio. Riders who skip food early because the legs feel good are the riders staring at a gel at km 20 and knowing it is too late.
Hourly plan:
| Hour | What to Eat | Notes | |------|------------|-------| | 1-2 | Drink mix (40-50g/hr) + 1 gel or bar per hour | Easy to absorb early, build the base | | 3-4 | Drink mix + real food (rice cakes, banana, energy bar) | Flavour variety prevents nausea | | 5-6 | Gels and drink mix, whatever sits comfortably | Gut tolerance drops, especially at altitude | | 7+ | Small gels and liquid carbs, frequent sips | Solid food may not stay down this deep and this high |
Pre-Stelvio fuelling. Eat a gel and drink 200-300ml of carb mix at the base of the Stelvio before you start climbing. Top your bottles up at the last feed zone. You want to start the 24km climb with full fuel tanks because eating becomes progressively harder as the altitude and effort combine.
Hydration. 500-750ml per hour in normal conditions, up to 1,000ml in the valley heat. At altitude, you may not feel thirsty — the air is cooler and drier, and the reduced blood flow to the gut suppresses thirst signals. Force-drink anyway. The hydration tool helps you dial this against bodyweight and expected conditions. Target 500-700mg of sodium per litre.
Pre-race. 8-10g of carbohydrate per kg of bodyweight the day before. Breakfast 3-4 hours before the start — 2-3g/kg of carbs, moderate protein, low fibre, low fat. Italian breakfasts lean towards pastry and coffee; supplement with your own porridge or rice if the hotel spread is thin.
Train your gut to this volume. At least four long training rides in the build phase should include the full 80-90g/hour protocol. The Stelvio at altitude is not the place to discover that your stomach rejects a new gel brand when the air gets thin.
Race Day Execution
Temperature Management
This is the single biggest logistics challenge of the day. You start in Bormio at 25-30°C and finish the Stelvio at 5-10°C. A temperature swing of 20°C across 24km of climbing is not an edge case — it is the standard condition.
What to carry: Arm warmers (rolled down in the valley, pulled up above 2,000m). A gilet in your back pocket — lightweight, packable, wind-blocking. Long-finger gloves in a pocket for the descent. If rain is forecast, a lightweight rain jacket instead of the gilet. The weight penalty is negligible. The insurance is significant.
When to layer up: Put arm warmers on at approximately km 15-16 on the Stelvio, when you pass through 2,000-2,200m. Put the gilet on at km 21-22, before the final exposed kilometres to the summit. Do this while you still have dexterity in your fingers. Riders who wait until the summit to layer up are fumbling with zips in 5°C wind with hands that have been gripping bars for six hours.
The Descent: 48 Hairpins Downhill
The Stelvio descent is 24km of tight switchbacks on a narrow road, and you will ride it tired, potentially cold, and with reduced grip strength. This is where the Stelvio claims riders who were otherwise having strong days.
Brake before corners, not through them. Scrub speed on the straight approach to each hairpin. Enter the corner at a speed you can hold without braking. Trail-braking through a hairpin on a tired bike with cold rims is how crashes happen.
Alternate braking hands. Two-finger braking, alternating dominant hand every five or six hairpins. Forearm pump from sustained braking is real — after 48 hairpins of continuous brake modulation, your grip strength can drop to the point where you cannot brake effectively. Alternate to distribute the load.
Stay wide. The inside of the hairpin is steeper, tighter, and less visible to oncoming traffic. The outside line gives you a wider radius, better sight lines, and more margin. Accept the extra distance. You are not racing the descent.
Temperature. At 60 km/h, a 7°C summit temperature has an effective wind chill closer to -5°C on exposed skin. That cold arrives instantly and accumulates over 24km of descending. If you are not layered up before you start the descent, you will not be able to layer up during it — your hands will be too cold and the road too demanding. The riders who descend comfortably are the riders who put on every layer at the summit before rolling over the top.
The Final Kilometres of the Climb
The last 3km to the summit are psychologically tricky. The gradient eases to 6-7% but the altitude is at its peak and the wind is often in your face across the exposed upper slopes. Riders who see the gradient ease and accelerate at km 22 crack at km 23. Hold your pace. The summit is coming. You do not need to race it.
When you cross the summit, stop for three minutes. Put on every layer you have. Eat something. Drink. Let your heart rate drop to Zone 1 before you start the descent. Those three minutes at the top are the difference between a controlled 48-hairpin descent and a white-knuckled survival exercise.
Frequently Asked Questions
The answers above cover the detail, but here are the questions we get most from riders inside Not Done Yet who are targeting the Stelvio.
Can I train for the Stelvio without access to big climbs? Yes, but you need to simulate the duration and intensity. Indoor trainers with gradient simulation can replicate sustained 60-90 minute climbing efforts. Outdoor riders in flat terrain should use overgeared intervals and long tempo blocks to simulate the muscular cost. That said, at least two weekends on real mountain terrain during the build phase are strongly recommended — the bike handling on steep hairpins, the heat management across altitude changes, and the mental load of a 90-minute climb cannot be fully replicated on a turbo trainer.
How do I account for the altitude if I live at sea level? You cannot fully replicate the oxygen deficit of 2,758m in training. What you can do is build a larger aerobic margin — train your threshold higher so that climbing at 75-80% of your sea-level FTP still represents a manageable effort even with a 20-25% altitude penalty. Arrive in Bormio 2-3 days early to partially acclimatise. And pace the climb on power, not on feel — your perceived effort at 2,500m will be significantly higher than the same wattage at sea level.
Should I ride the inside or outside of the hairpins? Outside. Always outside, unless the road is completely clear. The inside line of a hairpin on a 10% gradient adds 2-4% to the effective gradient at the apex. On a 12% section, that means 14-16% on the inside versus 10-11% on the outside. The extra 20 metres of road on the outside costs 5-10 seconds. The energy saved by avoiding a 16% pitch at km 12 is worth several minutes on the upper mountain.
What if rain is forecast on race day? Rain on the Stelvio changes the event significantly. The descent becomes slower, colder, and more technical. Swap the gilet for a full rain jacket. Add long-finger gloves and a cycling cap under your helmet. Consider overshoes. The time cost of carrying extra clothing is trivial; the cost of descending 48 wet hairpins while hypothermic is not. If conditions are truly severe, there is no shame in a conservative descent — arrive at the bottom cold and slow rather than not arriving at all.
Is the Granfondo Stelvio harder than La Marmotte? Different, more than harder. La Marmotte is longer (174km vs 151km), has more total climbing (5,180m vs ~4,000m), and finishes on Alpe d'Huez. The Stelvio is shorter but reaches a higher altitude (2,758m vs 2,642m for the Galibier), has steeper sustained gradients (the 12-14% section between km 8-14 is tougher than anything on the Marmotte route), and the 48-hairpin descent adds a technical dimension that the Marmotte does not have. If altitude and steep gradients are your weakness, the Stelvio is harder. If cumulative distance and multi-col fatigue are your weakness, the Marmotte is harder. Both demand 16 weeks of specific preparation and neither forgives under-fuelling.
