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Race Your Fastest Ironman Bike Split and Run Stronger

Best Bike Split turns your power, course, and conditions into a precise Ironman bike pacing plan — so you're ready to run a strong marathon.

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Full Ironman racing is won or lost on the bike — not by going fast, but by going exactly right. Too aggressive in the first 60 miles and the back half of the course becomes damage control. Too timid and you surrender minutes you'll never recover on the run. Best Bike Split's physics-based modeling creates Ironman-specific pacing plans that maximize your 112-mile bike split while protecting the legs you'll need for 26.2 miles of running — dialed in to your exact course, conditions, and fitness.

The Ironman Bike Pacing Challenge

Ride 112 Miles Without Destroying Your Marathon

The Ironman bike leg is the longest, most consequential discipline in triathlon. The margin for pacing error is razor thin — and the consequences play out over 26.2 miles of running. The solution? Science-based variable power pacing built specifically for the demands of full Ironman racing.

The Problem

Traditional steady-state pacing — like riding a flat 70% of FTP for all 112 miles — ignores course reality. Long climbs, exposed wind sections, technical descents, and the slow accumulation of muscular fatigue across six or more hours all create moments where steady watts leave speed on the table or quietly push you past your sustainable ceiling.

The BBS Solution

Best Bike Split analyzes your entire Ironman course — elevation changes, road surfaces, wind direction — and calculates the exact variable power targets to maximize bike speed while managing fatigue before the marathon. The result is a custom plan built around your fitness and your course, not a generic percentage to guess at.

The Result

Ironman athletes using Best Bike Split consistently report faster bike splits paired with stronger marathon performances. Our algorithms eliminate the most common full Ironman mistake: going just 3–5% too hard in the first half of the bike and paying for it across all 26.2 miles of the run.

Our Top Features

Everything You Need for Your Perfect Ironman Bike Leg

Predict your Ironman bike split, plan your power from your own data, and step off the bike in T2 ready to run a marathon — not just survive one. Get more information about our top features, including the new Course Builder.

Predict your exact Ironman bike split before race day

Know your target time before you ever toe the line, with accuracy within 2–3% when power data and conditions are correct. Understand exactly where on your specific Ironman course you'll gain time on climbs or lose it in a headwind — and plan your race strategy around it.

Optimize power so you run your best marathon

Our Ironman-specific algorithms calculate the power ceiling that maximizes bike speed without compromising run performance. See projected Training Stress Score (TSS), Intensity Factor, and fatigue metrics calibrated for a 112-mile bike leg followed by 26.2 miles of running — not just the bike split in isolation.

Train the exact demands of your Ironman, indoors or outdoors

Upload your Ironman race plan to Zwift, TrainerRoad, or your smart trainer for indoor workouts that replicate your exact race-day power profile mile by mile. Take it outside with workout files for Garmin or Wahoo devices for course-specific outdoor training before race day.

Follow real-time power guidance on your Garmin or Wahoo

Execute your perfect Ironman pacing plan on race day with turn-by-turn power targets loaded directly to your bike computer. See your plan, current power, and time ahead or behind pace in real-time throughout the 112-mile bike leg — so you never have to guess whether you're on track.

Choose the fastest equipment and race strategy for your Ironman

Model different scenarios before race day: aero wheels vs. lightweight, aggressive position vs. comfortable, conservative first loop vs. pushing the hills early. Understand the time impact of every equipment and pacing decision so you show up on race morning with zero guesswork.

See how fitness, drag, weight, and weather change your Ironman time

Test what-if scenarios before committing to your plan. See how losing 5 pounds impacts your split on a hilly Ironman course. Understand how a sustained headwind over miles 60–90 should change your pacing strategy. Model different FTP levels to set realistic finishing goals — all with our Time Analysis Tool.

Pace the 112 miles perfectly so you have legs for the marathon

The most common Ironman mistake is overcooking the bike by just 3–5% — it feels manageable at mile 40 and costs you 20–30 minutes across the marathon. Best Bike Split's variable power algorithm prevents that error before it happens. Our plans account for cumulative fatigue across a full day of racing, ensuring you don't exceed sustainable effort even when competition tempts you to push harder than your plan allows.

Learn from real ride data to race smarter every season

Upload your actual Ironman race files and compare against your plan. See where you held target power and where you deviated. Analyze the impact of those pacing variations on your run performance. Use these insights to refine your strategy for the next race and continuously improve your Ironman execution season over season.

Plan with physics-based modeling trusted by pros

Best Bike Split's algorithms are used by World Tour cycling teams and professional triathletes — including pro TJ Tollakson, who used BBS to achieve a record-breaking Ironman performance — to optimize race performance. The same physics-based modeling is available to age group Ironman athletes. Our math accounts for aerodynamics, rolling resistance, gradient, wind, and power output to calculate the fastest possible way to complete your Ironman course.

Start race morning with total confidence in your Ironman strategy

Eliminate pre-race anxiety about pacing. Walk into T1 knowing exactly what power to hold on every section of the course. No more guessing whether to push the opening miles or stay conservative through the windy back half. Execute your plan with complete confidence that it's optimized for your fastest 112-mile bike split — and your strongest possible marathon.

Triathlon Pacing Plans

How Ironman Pacing Compares to Other Triathlon Distances

Sprint Triathlon Bike Pacing

With a short, intense bike leg followed immediately by a 5K run, sprint triathlons require disciplined threshold pacing. Our plans typically target 85-95% of FTP depending on course profile and your run strength, with precise power targets that prevent early fatigue while maximizing bike speed.

  • Predict your exact bike split before race day
  • Dial in aggressive pacing without blowing up your run
  • Optimize speed for short, high-intensity efforts
  • Execute perfectly with real-time power targets
85–95%
FTP Target
12–20 mi
Bike Distance
5K
Run Distance
age group triathlete using power pacing for a sprint triathlon

Olympic Distance Power Plans

Olympic distance racing demands careful power management at and near threshold. Best Bike Split helps you find the power ceiling that allows for a competitive 40K bike split without compromising your 10K run performance. Most athletes target 80-85% FTP with strategic surges on key sections.

  • Find the fastest sustainable 40K power
  • Balance bike speed with a strong 10K run
  • Model terrain, wind, and course dynamics
  • Train precisely for race-day demands
80–85%
FTP Target
40K
Bike Distance
10K
Run Distance
olympic distance triathlon pacing with garmin

70.3 Bike Pacing Strategy

Half Ironman racing sits in the sweet spot of triathlon — more intensity than a full Ironman, more distance than Olympic. Most athletes target 75–80% of FTP across 56 miles, but the right number depends on your course profile, heat, your individual bike-to-run strength, and how the race is laid out. Best Bike Split models all of it.

  • Execute variable power across all 56 miles
  • Adapt pacing for hills, wind, and heat
  • Protect energy for a fast half marathon
  • Validate nutrition and effort before race day
75–80%
FTP Target
56 mi
Bike Distance
13.1 mi
Run Distance
70.3 athlete following precision pacing plan on bike leg

Ironman Bike Pacing Plan

The Ironman bike leg is a 112-mile exercise in patience and precision. Most age groupers perform best at 68–72% of FTP, but this varies significantly based on course difficulty, temperature, and individual run-to-bike strength ratios. See how pro triathlete TJ Tollakson used Best Bike Split to achieve a record-breaking Ironman performance with precise power pacing.

  • Distribute effort perfectly across 112 miles
  • Prevent late-race fatigue and pacing mistakes
  • Model heat, terrain, and endurance limits
  • Set up your strongest possible marathon
68–72%
FTP Target
112 mi
Bike Distance
26.2 mi
Run Distance
triathlete using power meter on Ironman bike course

Easy Setup

Create Your Ironman Pacing Plan in 3 Steps

triathlete power profile

Build Your Athlete Profile

Enter your FTP, weight, bike specs, and aero data to generate precise Ironman race predictions. Don't know your CdA? Our system can estimate it from your position and equipment or from a past ride — so you can start planning with confidence even without a wind tunnel.

triathlon specific courses

Select Your Ironman Course

Choose from thousands of existing Ironman courses — most Ironman-branded and independent full-distance events are already in our database — or upload your own GPX file. Our database includes detailed elevation profiles and road surfaces, plus historical or forecasted weather for accurate split predictions.

custom triathlon pacing plan

Your Personalized Ironman Plan

Receive a detailed, segment-by-segment Ironman bike pacing strategy with variable power targets optimized for every section of your 112-mile course. See your predicted bike split, Intensity Factor, TSS, and exactly how your pacing strategy balances speed with marathon readiness.

Train and Race with Your Plan

Download your plan to Zwift, TrainerRoad, or any ERG-mode trainer for indoor training. Export to Garmin or Wahoo for outdoor training rides and race-day execution. Practice makes perfect — rehearse your exact Ironman race plan in training before the big day.

Create Free Ironman Pacing Plan

Indoor and Outdoor Workouts

Train with Your Ironman Bike Pacing Plan

Indoor Course Simulation

Ironman training blocks demand specificity. Upload your Ironman plan to Zwift or TrainerRoad and ride the exact power profile you'll execute on race day. Practice holding watts on long sustained climbs, recovering efficiently on technical descents, and managing average power across wind-exposed sections — all from your pain cave, months before race day.

Outdoor Race Rehearsals

Load your Ironman pacing plan to your Garmin or Wahoo device for outdoor execution. If you can ride sections of the actual race course beforehand, do it with your plan loaded. If not, simulate the effort on similar terrain with the same duration and power profile. Follow your plan's power targets and build the muscular endurance and pacing discipline your body needs for confident race-day execution.

Long Ride Integration

Best Bike Split plans are built for Ironman-specific long rides. Execute your race-day power plan during your 4–6 hour training rides, then run off the bike to simulate race demands. This training teaches your body to manage glycogen, stay aerobically efficient at Ironman pace, and run on fatigued legs — and validates your bike pacing before money is on the line.

Progress Tracking

Compare your training rides against your plan. Are you holding the target watts across the full duration? Do you step off the bike feeling like you could run a marathon at target pace? Use real ride data to refine your plan, adjust FTP estimates, and dial in your race-day strategy before you ever cross the start line.

Wahoo/Garmin bike computer displaying Ironman power targets from Best Bike Split

Top Ironman Events

Use Best Bike Split for Your Next Ironman

DATEV Challenge Roth

The world's largest and most iconic iron-distance triathlon, set in the heart of Bavaria with a Main-Danube Canal swim, a rolling 180km bike through the Franconian countryside including the legendary Solarer Berg climb, and a marathon finish inside the Roth triathlon stadium before 300,000 spectators — a course where iron-distance world records are made and the ultimate benchmark for full-distance pacing strategy, normalized power output, and long-course race execution.

Ironman World Championship

The pinnacle of long-course triathlon and the sport's most iconic race, held annually in Kailua-Kona, Hawaii — featuring a 2.4-mile ocean swim in Kailua Bay, a 112-mile lava desert bike into brutal trade winds along the Queen Ka'ahumanu Highway, and a marathon along the coast finishing on Alii Drive. The defining test of ironman pacing strategy, heat management, aerobic threshold, and mental resilience in endurance sport.

Ironman Frankfurt

The Ironman European Championship for male professionals and all age-groupers, held in Germany's financial capital with a lake swim, rolling 180km bike through the Frankfurt countryside, and a city-centre marathon through packed crowds along the Main river — a flagship Pro Series race and key Kona qualification event ideal for modeling full-distance bike pacing strategy and championship-level race execution in a high-energy European setting.

Ironman New Zealand

One of the world's oldest and most celebrated iron-distance races, set in the lakeside town of Taupo on New Zealand's North Island — featuring a crystal-clear Lake Taupo swim, a challenging rolling bike through volcanic farmland, and a scenic two-loop run along the Waikato River. A 2026 Ironman Pro Series opener and Kona qualifying event steeped in long-course tradition, ideal for athletes targeting strong full-distance split times in a destination race environment.

Ironman Arizona

A perennially fast and flat iron-distance classic set in Tempe, Arizona — featuring a one-loop swim in Tempe Town Lake, a triple-loop bike on the Beeline Highway with consistent road surface and minimal elevation, and a flat two-loop lakeside marathon. Known as the "Valley of the PR," it's a go-to full-distance race for athletes targeting ironman personal records, optimizing normalized power output on a predictable course, and executing data-driven long-course pacing strategy.

Ironman Western Australia

The Ironman Asia-Pacific Championship set in the coastal town of Busselton — featuring a calm Geographe Bay ocean swim along the iconic Busselton Jetty, a flat and fast 180km bike through Margaret River wine country, and a pancake-flat run along the foreshore. A bucket-list destination race and major Kona qualifier well-suited for athletes targeting iron-distance PRs, testing aerodynamic efficiency, and executing flat-course pacing strategy in a world-class regional championship setting.

Ironman Switzerland Thun

A breathtaking alpine iron-distance race set against the Swiss Alps and Lake Thun, featuring a clear mountain lake swim, a challenging hilly 180km bike through the Bernese Oberland, and a two-loop run through the historic town of Thun — consistently rated among the highest in athlete satisfaction globally and a demanding course for athletes refining variable-terrain power modeling, elevation-based pacing strategy, and full-distance race execution in a stunning destination setting.

Ironman Kalmar

Voted the world's top-rated Ironman triathlon for overall athlete satisfaction, set in a charming coastal Swedish town with an ocean swim in the Kalmarsund, a flat and fast 180km bike through rural Småland, and a run through streets lined with some of the most passionate spectators in the sport — a 2026 Pro Series race and Kona qualifier that delivers an unmatched race-day atmosphere and ideal conditions for full-distance flat-course pacing strategy and split optimization.

Ironman Hamburg

The Ironman Women's European Championship set in Germany's port city — featuring an Alster lake swim, a rolling 180km bike through the Hamburg countryside, and a marathon through the city centre with electric crowd support. A premier Pro Series race and Kona qualifying event that has hosted iron-distance world record performances, making it a key course for athletes studying elite full-distance pacing models, power output benchmarking, and championship race strategy.

Full Ironman FAQs

Ironman Bike Pacing Questions

Most age group athletes perform best at 68–72% of FTP for a full Ironman — but the right number varies significantly based on your course profile (flat vs. mountainous), conditions (heat, wind, altitude), your personal bike-to-run strength ratio, and overall fitness. Best Bike Split models all of these variables to calculate your personal optimal power ceiling, not a one-size-fits-all percentage.

Full 140.6 Ironman racing demands meaningfully lower intensity than a 70.3 — typically 68–72% of FTP versus 75–80% for the half distance. The 112-mile bike leg and full marathon that follows leave almost no margin for pacing error. What feels like a sustainable 73–74% through mile 60 can quietly become a survival shuffle by mile 16 of the run. Best Bike Split accounts for race distance and your specific run fitness when calculating optimal Ironman power targets.

Olympic distance athletes push near threshold — 80–85% FTP — over just 40 kilometers. The Ironman bike leg is nearly three times longer in distance and five or more times longer in duration, which demands dramatically more conservative average intensity and far tighter fatigue management. The compounding cost of small pacing errors over 112 miles is unlike anything in shorter-distance triathlon.

While Best Bike Split can create heart rate-based plans and pace-based guidance, power meters are strongly recommended for Ironman racing specifically. Over a 5–7 hour bike leg, heat, fatigue, and caffeine make heart rate drift unreliable as a pacing metric. Power is the only consistent real-time signal available — and small differences in average power output have enormous run consequences at this distance.

Yes. Best Bike Split can estimate FTP based on recent ride data, or you can perform a standard FTP test to establish your baseline. We also provide guidance on translating your FTP into Ironman-specific training and racing power zones so you train at the right intensities for full-distance demands.

When power data, course information, and weather conditions are accurate, our physics-based modeling typically predicts Ironman bike split times within 2–3%. Thousands of athletes validate these predictions every season at Ironman-branded events and independent full-distance races worldwide.

It's the single biggest controllable factor in Ironman marathon performance outside of your base run fitness. By avoiding overcooking the first 40–50 miles and managing energy expenditure throughout the bike, you'll arrive in T2 with more glycogen, fresher legs, and the mental confidence to push the marathon. Athletes who nail the Ironman bike consistently run negative or even splits on the marathon — athletes who overcook it almost never do.

Yes. Our database includes the vast majority of Ironman-branded courses worldwide — from Kona and Frankfurt to local regional events. Select your course from the database or upload a GPX file for any event not already listed.

Absolutely. Best Bike Split works for any full iron-distance event regardless of brand — Ironman, Challenge, CLASH, or any independent 140.6-mile triathlon. Upload your course GPX file or build a custom course and our physics engine handles the rest.

Best Bike Split vs Old Methods

Why Best Bike Split Beats Traditional Ironman Pacing

Steady-state pacing works on a trainer. It doesn't work on a real Ironman course with mountains, wind exposure, and 112 miles of accumulated fatigue. Best Bike Split analyzes every element of your specific course to deliver a data-driven pacing plan that produces faster bike splits and stronger marathon runs.

Old School Method Best Bike Split Method

Ride Steady State Power

"Just hold 70% of FTP for the whole Ironman bike leg."

Variable Power Pacing

Calculate optimal power for every mile based on gradient, wind, road surface, and cumulative fatigue across a full day of racing.

The Problem

Real Ironman courses aren't flat training roads. Long climbs, sustained crosswinds, and 6+ hours of effort all impact optimal power output. Riding steady watts means overcooking climbs and bleeding energy — or under-pacing descents and losing time that never comes back.

The Result

Faster Ironman bike splits with less fatigue. More efficient use of your FTP across all 112 miles. A marathon that doesn't fall apart at mile 16.

Guessing your Ironman bike split from a previous race on a different course isn't a strategy. Best Bike Split models your exact course, your current fitness, your equipment, and expected race-day conditions to deliver accurate split predictions before you ever leave home.

Old School Method Best Bike Split Method

Guess Your Bike Split Time

"I went 5:30 on a flat course last year, so maybe 5:55 on this hilly one?"

Physics-Based Time Prediction

Model the exact Ironman course you're racing with your power, weight, equipment, and expected conditions.

The Problem

Every Ironman course is different. Elevation gain, wind exposure, road surface quality, and temperature can swing your bike split by 20–40 minutes. Past performance on a different course doesn't predict what you'll do on your next one.

The Result

Know your target Ironman bike split to within minutes before race day. Plan nutrition timing, run targets, and overall race strategy around accurate, course-specific time predictions.

Join 150,000+ Athletes Already Racing Smarter

Stop guessing at Ironman bike pacing. Stop following generic IF recommendations that don't account for your specific course, conditions, or fitness. Start using the same physics-based modeling trusted by pro triathletes and World Tour cycling teams — and race the Ironman you've been training for.

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  • Automatic Climb Detection
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  • Plan to Actual Comparison Tool
  • BBS AI Workout Builder
  • BBS AI Assistant
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  • Goal Race Time Model
  • Training Stress Score Model
  • Advanced Weather Feature
  • Advanced Surface Conditions
  • Time Analysis Tool

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  • Automatic Climb Detection
  • Race Analytics Tool
  • Plan to Actual Comparison Tool
  • BBS AI Workout Builder
  • BBS AI Assistant
  • Workout Sync (top platforms)
  • Goal Race Time Model
  • Training Stress Score Model
  • Advanced Weather Feature
  • Advanced Surface Conditions
  • Time Analysis Tool

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CANYON//SRAM Racing partners with Best Bike Split
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