The Bike at Barranquilla: 90 km on the Circunvalar with Heat, Rollers, and an Elevation Number to Take with a Grain of Salt

The course at a glance

The bike leg of IRONMAN 70.3 Barranquilla is a single 90 km loop with a long out-and-back stretch along the Circunvalar de la Prosperidad, on the outskirts of the city. The official classification is "rolling": neither flat nor mountainous, but constant ups and downs. The official course page lists 1,043 m of elevation gain. Take that number with caution: for a Caribbean coastal city it seems high, but it's the only figure published. Until more GPS files from race reports show up, plan for the worst-case scenario: 1,000 m of climbing spread across short, repeated kickers.

Several reports from the first edition (June 2026) describe a race that was hard mostly because of heat and humidity, not gradient. One age-group athlete interviewed after the race called it one of the costliest races he'd ever done, explicitly citing heat and humidity as the deciding factors.

Out-and-back: what it means in practice

On the out-and-back section you'll pass other athletes on the same road. Three practical consequences:

• Drafting rules: with athlete traffic in both directions, the marshals have an easy job. Keep the legal gap and make your passes decisively.
• Visual references: you'll see who's ahead of and behind you. Good for morale, dangerous for pacing. Don't chase anyone.
• Safety: at turnarounds and in tight spots, slow down before, not during.

Pacing: 5-10 watts below your target

This is not a race where the bike makes your result. With official highs of 34°C and Caribbean humidity, the bike is where you build — or destroy — your half marathon. The rule of thumb: ride 5-10 watts below the target you'd use at a 70.3 in temperate conditions. On the rollers, work on steady power: no spikes on the kickers, no fully coasting the descents.

If you don't ride with a power meter, go by feel: in the first 30 km you should feel like you're going too easy. If at the halfway point of the bike you feel "good but on the limit," you're already over.

Hydration: the bike is your window

With a 34°C high, the bike leg is the only part of the race where you can drink and take in sodium systematically without paying a mechanical cost. Set a timer: drink every 10-15 minutes from the very first kilometer, not when you're thirsty. Your fluid/sodium plan needs to be tested in training in hot sessions, because many nutrition plans that work at 20°C fall apart above 30°C.

Equipment and gearing

With the listed elevation gain, don't show up with an extreme single chainring or flat-TT gearing. A cassette that lets you climb the kickers seated and at high cadence (90+) protects your legs for the run. Check the wind in the days before: on a coastal out-and-back, a steady wind means half the leg with a tailwind and half into a headwind — plan your effort accordingly and don't be fooled by your speed on the way out.

What to do now

1. Train rollers at steady power: sessions with repeated 1-3 minute kickers at race power, without exceeding it. 2. Test your hydration in the heat: at least 3-4 long rides during the hot hours with your final fluid/sodium plan. 3. Pick your gearing now: if you're torn between two cassettes, choose the easier one. 4. Watch the race reports: the race is young and real-world data (GPS files, wind, pavement quality) will emerge from the coming editions. Before you fly out, look for files from the first edition to verify the actual elevation gain.