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Race IntelligenceErkner, Germany

IRONMAN 70.3 Erkner

Know your day before you race it.

Enter four numbers you already train with. You get a likely finish range, target paces and watts, and how I would race this course.

Race day
12 September 2027
Swim
1.9 km
Bike
90 km
Run
21.1 km

Published route evidence. Final 2027 route pending. Checked 19 Sept 2026.

Official course routeThe real GPS route for each discipline with official GPX data available, drawn in one shared coordinate space.

01 Race Card

Build my Race Card

Your first range uses conservative assumptions. Add optional evidence to make it more specific. It is calculated in your browser and saved only on this device.

Your numbers
Distance unit
Weight unit
You and this race
Sharpen your range with more detailOptional. Recent swim, bike and run results, equipment and transitions.

Add only the evidence you have. Every control changes a discipline range, its uncertainty, or an execution-risk explanation.

Swim evidence

Replaces the broad pool-to-open-water assumption.

Bike and equipment

These replace broad mass, aerodynamics, tyre, and power-to-speed assumptions.

Run evidence

A recent effort and honest durability/acclimation answers refine the post-bike run.

Race execution

Transition proficiency changes the T1/T2 range and how wet conditions are treated.

02 The course

What Erkner actually gives you

You swim one calm loop of the Dameritzsee at Strandbad Erkner, ride a flat, fast two-loop 90 km course on newly-paved roads along the River Spree into the Brandenburg countryside, then run four flat loops through Erkner's marketplace, past the Gerhart-Hauptmann-Museum, with strong local crowd support. Just outside Berlin, this course offers genuine personal-best terrain throughout. Nothing here forces you to ease off, which is exactly why holding a planned power number on the bike, rather than the road's own pace, decides how the four-loop run actually goes.

Show distances in

Swim

1.9 km

Lake, One Loop

Layout
1 loop
Setting
Strandbad Erkner, on the Dameritzsee

A calm, one-loop lake swim in the Dameritzsee's clean, clear water gives a straightforward, low-drama start at the gates of Berlin.

Source: 2023 file, current course page

Bike

90 km

Flat, Fast, Two Loops

Layout
2 loops
Setting
newly paved roads along the River Spree into the Brandenburg countryside

A flat, fast two-loop course on newly-paved roads along the Spree removes terrain as an excuse, so power discipline alone decides the leg.

Source: 2026 file, current course page

Run

21.1 km

Flat, Four Loops Through Town

Layout
4 loops
Setting
Erkner's marketplace and the Gerhart-Hauptmann-Museum

A flat four-loop course through Erkner's marketplace, with strong local spectator support, rewards whatever the flat bike left in the legs.

Source: 2026 file, current course page
Where these course facts come from

These facts come from the organiser’s latest published material: swim, 2023 file, current course page; bike, 2026 file, current course page; run, 2026 file, current course page. They describe the character of the course. They do not confirm the final 2027 route.

03 Race plan

How I’d want you to race it

One job for each part of this course. The distance markers tell you when the job changes. The course tells you why.

Swim

A calm, one-loop lake start

  1. 0–1900 m

    One loop of the Dameritzsee

    Settle into calm, clean water

    Flat wooded banks and clean, clear water at Strandbad Erkner give a genuinely low-drama opening. Settle into rhythm rather than racing a swim that offers nothing to fight.

    • Settle by 300 m
    • Hold a controlled, repeatable effort

Bike

Flat and fast, one honest number

  1. 0 km–22.5 km

    First loop along the Spree

    Set a ceiling before the smooth new roads tempt a PR pace

    Newly paved, flat roads along the River Spree make this course genuinely fast, and genuinely easy to over-ride. Set the power number you can hold for two full loops.

    • Cap power in the first 15 minutes
    • Fuel early on the smooth roads

  2. 22.5 km–45 km

    Closing the first loop

    Finish loop one at the pace you'll repeat

    As the first loop closes back through the Brandenburg countryside, hold the discipline you'll need for an identical second loop.

    • Stay on the fuelling schedule
    • Keep power consistent through the closing kilometres

  3. 45 km–90 km

    Second loop

    Match loop two to loop one exactly

    The second loop repeats the same flat, fast terrain. Ride to the same power ceiling, especially through the sections that felt easy the first time.

    • Compare effort to loop one
    • Finish planned nutrition before T2

Run

Four flat loops through Erkner

  1. 0 km–5.3 km

    Loop one through the marketplace

    Let the flat course feel easy on purpose

    The run passes Erkner's beautiful marketplace and the Gerhart-Hauptmann-Museum with strong local support. Nothing here should feel hard yet.

    • Shorten stride out of T2
    • Hold opening pace regardless of the crowd

  2. 5.3 km–10.55 km

    Loop two

    Use the repeat as an honest check

    Passing the same marketplace and museum a second time gives a clear read on how loop one's pace is actually holding.

    • Compare loop two to loop one
    • Keep aid-station fuelling on schedule

  3. 10.55 km–15.8 km

    Loop three

    Protect what a flat, fast bike left you

    This is where a hard-ridden bike, even on flat terrain, starts to show up in the legs. Manage the effort you actually have.

    • Reassess goal pace honestly
    • Keep taking aid on schedule

  4. 15.8 km–21.1 km

    Final loop to the finish

    Spend what an honest bike left you

    The final loop finishes among Erkner's strongest crowd support. If the bike was paced evenly across both loops, this is where it pays off.

    • Decide the finish honestly
    • Save something for the final loop

04 Race week

What I would keep an eye on

There is no useful 2027 forecast this far out. For now, past race dates give us a point of reference. Closer to the race, the forecast will tell us whether the plan needs changing.

Forecast statusToo early for a forecast

A race-day forecast is not meaningful yet; check back closer to the event.

Temperature
13.0–24.6°CDew point centred on 12.2°C
Wind and gusts
12.1 km/hGusts up to 43.6 km/hPrevailing direction SW
Rain likelihood
Up to 80%Wet-surface uncertainty retained

Historical baseline, 2019–2025 · Open-Meteo historical archive · Updated 2026-09-19.Historical comparison only. This is not a forecast for 2027.

05 Method

What goes into your range

Your CSS, FTP, weight and run threshold create the first range. Open-water, bike, run and execution evidence can replace broad assumptions. Course data and the historical conditions baseline shape every simulation.

  1. Your numbersCSS · FTP · weight · run threshold
  2. This raceDistance · water type · elevation · exposure
  3. Your Race CardFinish and discipline ranges, with target paces and watts

Confidence is built from four inputs

Athlete evidence
Builds with recent open-water, bike and run efforts
Bike setup
Builds with equipment, mass, aero and tyre detail
Course evidence
Partial while the 2027 route is unconfirmed
Race-week conditions
Historical baseline until a forecast is useful
How the model works

It starts with the targets in your Race Card, then samples the parts of a 70.3 that vary: open-water pace, transitions, bike speed at the planned power, and the drop in run performance after the swim and bike. Repeating that calculation produces a likely range rather than a single heroic number.

The current time calculation uses this race’s published distances, or standard 70.3 distances where none are published, with the available course headings, elevation and exposure evidence. Weather scenarios vary temperature, dew point, wind, gusts, rain and water conditions together. Unknown route detail stays visible as uncertainty rather than false precision.

It is not predicting your exact finishing time, placing, or race-day weather. It answers a narrower question: given the plan and the information we have, what range of day is plausible, and where is the uncertainty coming from?

Confidence is not a permanent “low”. It is recalculated across four separate inputs:

  • Your evidence: consistent inputs and recent race-like swim, bike, and run results.
  • Bike setup: measured or specified aerodynamics rather than a broad prior.
  • The course: verified distance and route character, including elevation and technical sections.
  • The conditions: a current forecast is more useful than a historical comparison.

It starts low when those inputs are broad. It can become moderate or high as the evidence improves. A narrower range means better information, not a guarantee.

06 Next steps

If Erkner is your race

Your range is built on today’s numbers. The months of training before race day decide what those numbers become.

The work from here.

Self-guided routeHalf-distance training plansTraining plans for the pacing discipline this course rewards.See the plans Personalised routeWork with me on the whole buildCoaching when you want the plan and race decisions joined up.See coaching

Further reading

ArticleHow to pace a 70.3 so you can still runThe longer version of the pacing logic behind this Race Card.ArticleFix the first ten minutes off the bikeUseful before a four-loop run that starts right after a flat, fast bike.

Evidence

Sources and verification

Course status: Partially verified. The organiser’s descriptions and latest published route profiles are in use. The final 2027 route is not yet confirmed. Last checked 19 Sept 2026.