The Bike Leg at 70.3 San Juan: 90 km of Steady Watts

The bike is the leg that decides this race. Not because of the climbs—there aren't many—but because of your ability to hold steady power for hours on a course that gives you no excuses and no variety.

The Numbers First

90 km, listed as rolling by the organizer. Official elevation gain is 334 m, but a third-party profile measures around 553 m. That's not a minor detail: a 220 m difference changes your gearing choices and time estimates. Until the final GPS track is out, work with a 330-550 m range. Once the track drops, load it onto your bike computer and recalculate everything on the actual profile. Don't trust a single elevation figure: the sources disagree, and we're saying that plainly.

What the Course Looks Like

According to the third-party profile, the 90 km break down like this: over 53 km of flat, roughly 10 km of false flat climbing between 1 and 3%, about 6.5 km of real climbing above 3%, and roughly 21 km of descending. Translation: more than half the race is ridden in the aero position at steady watts.

The 1-3% false flat is the trickiest stretch. It doesn't feel like a climb, but your speed drops and the temptation to push harder to get it back is strong. That's where you lose the most time without noticing. Train yourself to recognize that gradient and hold the same power you'd ride on the flat—not more.

The Descents: 21 km You Can't Give Away

21 km of descending is a lot. It's not a reward, it's an opportunity: keep pedaling lightly, stay aero where the road allows, and use those stretches to drink and eat when your heart rate drops. Riders who stop pushing on descents hand minutes to those who don't.

The Altitude: Small, But Real

The race area, Las Tapias, sits at about 925 m. It's not the real Andes, but if you live and train at sea level you'll feel a small extra effort: slightly thinner air, perceived watts a touch higher. The effect is modest but real. The countermeasure is simple: don't go out above pace in the first 20 km. Let your body find its equilibrium, then settle into your target.

The Wind: Missing Data

There's no verified public wind data for this race: the information isn't available. Caution is mandatory, because 53 km of flat in open terrain at the foot of the Andes can leave you very exposed. Plan B is mental before it's technical: if it's windy on race day, think in watts, not speed. A headwind managed at steady power costs far less than a headwind fought in surges. Check local conditions in the days before the start.

Pacing and Gearing

This race is won on consistency, not surges. Set a sustainable power target and defend it for 90 km. In training, build long blocks of 60 to 90 minutes in the aero position without coming off the extensions: holding the position matters as much as the watts.

On gearing: a flat-course setup, with a few extra teeth in the back for the 6.5 km above 3%. You don't need a mountain cassette—you need to avoid grinding out of your range on the steep sections and breaking your rhythm.

What to Do Between Now and Race Day

• Download the course GPS track as soon as it's available and compare it with the third-party profile.
• Train long aero blocks at steady power, not short hill repeats.
• Test your chosen gearing on a 1-3% false flat near home.
• Pack arm warmers or a vest: average lows are 11 °C and you'll come out of the swim wet.
• Decide your wind plan in advance: watt target unchanged, speed takes care of itself.