The Cascais 70.3 Bike Course: 90 Hilly Kilometers That Reward Steady Riders

The Big Picture

90 km in a single loop, 771 m of official elevation gain. On paper it's a hilly course. In practice it's a fast, flowing course that punishes anyone who rides it in surges. There are no walls: the average gradient on the main climb stays under 2%. The difficulty isn't the climbing. It's the relentlessness of the effort.

The Main Climb: Long, Not Hard

The key climb is about 10 km long. It's not steep, apart from two short kicks. You can ride it on standard gearing, no mountain cassette needed. Here's the point: this is not where the race is won. Anyone attacking it at 20-30 watts above threshold pays for it on the rollers that follow and then on the run. Ride the climb at your half-distance power target, slightly above at most, and let the faster climbers go.

The Coastal Rollers and the Inland Kicks

After the climb comes the section that decides the race: constant rollers along the coast toward Lisbon, plus two short inland stretches. The gradient changes constantly here. One rule applies: constant power or effort, not constant speed. Push the same on the climbs and the false flats, and don't surge over the top of every rise. Riders who go by feel for "speed" on this course end up with a sawtooth power file and empty legs in T2.

The Lap at Estoril

The course includes a lap of the Estoril motor racing circuit. Perfect tarmac, wide corners, zero traffic: it's the fastest and safest stretch to hold your aero position. Enjoy it, but don't turn it into a personal time trial: it's a passage, not a segment to chase.

Wind: Your Mandatory Plan B

In the days before the 2025 race, strong wind was reported along the coast. There's no guarantee it will return, but you need to be ready. Two concrete actions:

• Manageable wheels: if you're torn between a deep-section and a mid-depth wheel, go mid-depth. A crosswind gust on the coastal road with an 80 mm up front is no fun.
• Practice riding aero in gusts: do at least one ride in your aero position with crosswinds before race day. You need to know how your bike reacts, not find out at km 40.

Drafting and Fair Play

Several 2025 race reports mention draft packs with no visible referee motos on the course. Two practical takeaways. First: race clean, regardless. Second, more important for your result: don't get sucked along. When a train passes you, the instinct is to jump on or surge. Both choices take you out of your watts. Let them go, watch your head unit, ride your own numbers.

What to Do Before the Race

• If you arrive a few days early, do a recon of the main climb: it takes away the anxiety and confirms it's rideable.
• Set a single power target for the whole leg and two caps: a maximum for the kicks, a minimum for the pedal-able descents.
• Choose your wheels based on the week's weather, not on what looks best in photos.

The Decision You Need to Make

On this course, you win the bike leg by not losing it. Ballpark times range from 2:25 for a top age-grouper to 3:25 for a relaxed finisher. Whatever your level, the goal is to get to T2 with legs ready to run a half marathon that, as we'll see, doesn't give you a single flat meter for free. If you have to choose between 3 minutes gained on the bike and 10 lost on the run, the math is simple.