Ironman 70.3 Bike Training: 10 Key Sessions

SUMMARY
This post presents 10 key bike sessions designed specifically for Ironman 70.3 athletes. Each workout targets a critical element of race readiness, from long endurance rides that build aerobic capacity, to tempo and threshold sessions that sharpen pacing and muscular resilience. With clear zone guidance (HR, FTP, RPE) and structured sets, these sessions help you develop the power, efficiency and confidence needed to conquer the 56-mile bike leg and run strong off the bike. Whether you’re building toward your first 70.3 or aiming to improve your PR, this guide will elevate your training.

The key elements of structured Ironman 70.3 bike training

A structured Ironman 70.3 bike plan should develop endurance, race pacing, strength and efficiency. All while teaching your body how to fuel and recover optimally. Every session should serve a purpose, whether it's building aerobic power, dialling in race-day pacing or improving your ability to take on nutrition under fatigue. The right mix of workouts prepares you to ride strong and transition smoothly into the run.

Bike Training Zones: HR, FTP and RPE

Understanding your bike training zones is essential for building structured Ironman endurance, strength and speed. Each zone targets a specific adaptation and helps guide intensity based on heart rate, power and effort.

Zone 1 / Recovery
68–73% of max heart rate, <55% FTP, RPE 1–2 (very easy)

Zone 2 / Endurance
73–80% of max heart rate, 56–75% FTP, RPE 3–4 (easy to moderate)

Zone 3 / Tempo
80–87% of max heart rate, 76–90% FTP, RPE 5–6 (comfortably hard)

Zone 4 / Threshold
87–93% of max heart rate, 91–105% FTP, RPE 7–8 (hard but controlled)

Zone 5 / VO2 Max
93–100%+ of max heart rate, 106–120% FTP, RPE 9–10 (very hard)

Use these zones to guide your interval sessions, race prep and recovery rides. When you train with precision, you race with purpose. These sessions will help you build the power and resilience needed to dominate the 56-mile ride.

10 Key Ironman 70.3 Bike Workouts

1. Long Endurance Ride

Purpose: Build aerobic capacity and teach fueling control

Warm-Up: 15 min spin
Main Set: 2.5–3.5 hr @ Zone 2
Cool-Down: 10 min easy spin

2. Broken Tempo Blocks

Purpose: Accumulate controlled tempo work in manageable chunks

Warm-Up: 15 min spin
Main Set: 4 x 20 min @ Zone 3 (5 min easy spin between)
Cool-Down: 10 min easy spin

3. Double Threshold Set

Purpose: Raise aerobic power and prepare for late-race intensity

Warm-Up: 15 min spin
Main Set: 2 x 15 min @ Zone 4 (6 min easy spin between)
Cool-Down: 10 min easy spin

4. Progressive Build Ride

Purpose: Practice smooth intensity changes to mimic race effort

Warm-Up: 15 min spin
Main Set: 30 min @ Zone 2 + 20 min @ Zone 3 + 10 min @ Zone 4
Cool-Down: 10 min easy spin

5. Tempo Finish Ride

Purpose: Train strength to hold form under fatigue

Warm-Up: 15 min spin
Main Set: 90 min @ Zone 2 + 30 min @ Zone 3
Cool-Down: 10 min easy spin

6. Long Tempo Ride

Purpose: Maintain race-pace pressure for extended periods

Warm-Up: 15 min spin
Main Set: 1 x 90 min @ Zone 3
Cool-Down: 10 min easy spin

7. Threshold into Tempo Combo

Purpose: Combine high-end power with steady-state control

Warm-Up: 15 min spin
Main Set: 2 x 8 min @ Zone 4 + 40 min @ Zone 3 (4 min easy spin between thresholds)
Cool-Down: 10 min easy spin

8. Over-Under Race Control

Purpose: Teach the body to handle pace shifts around target effort

Warm-Up: 15 min spin
Main Set: 5 x (5 min @ Zone 3 + 5 min @ Zone 4)
Cool-Down: 10 min easy spin

9. Big Gear Strength Ride

Purpose: Develop muscular endurance and force output

Warm-Up: 15 min spin
Main Set: 4 x 12 min @ Zone 2 in a big gear (low cadence) (5 min easy spin between)
Cool-Down: 10 min easy spin

10. Race Simulation Ride

Purpose: Mimic race effort for pacing, fueling, and mental prep

Warm-Up: 15 min spin
Main Set: 90 km (56 miles) @ Zone 2/3
Cool-Down: 10 min easy spin (or short transition jog)

Common Mistakes in Ironman 70.3 Bike Training

Even strong riders can miss the mark if training lacks precision or race focus.

Avoid these pitfalls to make the most of every session:

• Starting Intervals Too Hard: Pacing errors early can sabotage the full workout. Ride controlled and build into the effort.

• Skipping Race-Pace Work: Riding only easy or all-out leaves a gap in the middle. You need to train the intensity you’ll actually race at.

• Not Practicing Fueling: Nutrition should be second nature. Skipping race-day nutrition strategy in training is a costly oversight.

• Avoiding Long Intervals: 70.3 bike fitness is about sustained power. Short intervals alone won’t prepare you for 90 km of controlled effort.

Train with specificity, nail your pacing and treat every ride as a chance to sharpen execution.

FAQ: Ironman 70.3 bike sessions

How many bike sessions per week should I do for Ironman 70.3?

Aim for 2–3 key rides per week, mixing endurance, race-pace efforts and strength-focused sessions.

How early should I start bike-specific sessions before race day?

Begin 16–20 weeks out, progressively building intensity and duration toward peak race fitness.

Do I need to practice fuelling on the bike?

Absolutely. Practicing your race-day nutrition strategy during long rides is critical for avoiding bonking and maximising performance.

Should I always stay in aero position during race simulation rides?

Yes, to get comfortable maintaining aero for long periods and to simulate race-day conditions as closely as possible.

FURTHER READING: BUILD YOUR IRONMAN 70.3 BASE

• Ironman 70.3 Training: What Is Zone 2 / Endurance?

• Ironman 70.3 Training: What Is Zone 3 / Tempo?

• Ironman 70.3 Training: What Is Zone 4 / Threshold?

• Ironman 70.3 Training: What Is Zone 5 / VO2 Max?

• Ironman 70.3 Swim Training: 10 Essential Sessions

• Ironman 70.3 Run Training: 10 Essential Sessions

• Ironman 70.3 Training: Recovery Week

• Ironman 70.3: Beginner’s Guide

Final Thoughts

These 10 carefully structured bike sessions are thoughtfully designed to progressively build the endurance, power and efficiency that are essential for achieving success in an Ironman 70.3 race. It is crucial to consistently prioritise proper fuelling and hydration during every ride to ensure you maximise your overall performance and maintain steady energy levels throughout race day. By following this approach, you will be better prepared to tackle the challenges of the course with confidence.

Which of these key rides will you conquer first to level up your Ironman 70.3 training?

Always consult with a medical professional or certified coach before beginning any new training program. The information provided is for educational purposes only and is not a substitute for personalized advice.