Ironman Bike Training: 10 Key Sessions

SUMMARY
Ironman bike training isn’t just about surviving 112 miles, it’s about riding strong, steady and smart. These 10 key sessions are designed to build deep aerobic endurance, race-day pacing control, muscular strength and fuelling efficiency. From long Zone 2 rides to double threshold intervals, each workout helps prepare your body and mind for the demands of race day. By training with purpose and structure, you’ll arrive at T2 ready to run, not just recover.

Why Your Ironman Bike Training Matters

Training for an Ironman is a massive undertaking and building a rock-solid cycling foundation is crucial to success. The bike leg alone covers 180.2 km (112 miles) and how you perform on the bike can make or break your race day. Cycling is the longest discipline in an Ironman triathlon, both in distance and in time spent racing.

Nailing your bike training improves not only your bike split but also sets you up for a strong marathon. Poor bike pacing, lack of endurance or nutrition mistakes can destroy your run. That’s why it’s critical to balance long aerobic rides, race-specific intervals, strength work and nutrition practice. Here’s how to structure your sessions for success! In this post, we’ll dive into 10 essential Ironman bike sessions that build endurance, strength, race-specific fitness and confidence for the big day!

Bike Training Zones: HR, FTP and RPE Explained

• Zone 1 (Recovery): 68–73% HR - <55% FTP - RPE 1–2

• Zone 2 (Endurance): 73–80% HR - 56–75% FTP - RPE 3–4

• Zone 3 (Tempo): 80–87% HR - 76–90% FTP - RPE 5–6

• Zone 4 (Threshold): 87–93% HR - 91–105% FTP - RPE 7–8

• Zone 5 (VO2 Max): 93–100%+ HR - 105–120% FTP - RPE 9–10

The 10 Essential Ironman Bike Sessions

1. Long Endurance Ride

Purpose: Build aerobic capacity and train fueling over race duration

Warm-Up: 15 min spin
Main Set: 3–4 hr @ Zone 2
Cool-Down: 10 min easy spin

2. Broken Tempo Ride

Purpose: Accumulate steady race-pace work in manageable blocks

Warm-Up: 15 min spin
Main Set: 3 x 30 min @ Zone 3 (10 min easy spin between)
Cool-Down: 10 min easy spin

3. Double Threshold Set

Purpose: Increase top-end aerobic power under fatigue

Warm-Up: 15 min spin
Main Set: 2 x 20 min @ Zone 4 (5 min easy spin between)
Cool-Down: 10 min easy spin

4. Over-Under Intervals

Purpose: Train body to shift between tempo and threshold demands

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

5. Big Gear Endurance

Purpose: Build muscular strength and steady-state control

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

6. Progressive Race Prep Ride

Purpose: Progress effort through race-day zones to simulate build

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

7. Long Tempo Ride

Purpose: Sustain Ironman pacing under controlled pressure

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

8. Brick Simulation Ride

Purpose: Prepare for Ironman bike-to-run transition

Warm-Up: 15 min spin
Main Set: 2 x 20 min @ Zone 3 + 15 min @ Zone 4 (5 min easy spin between)
Cool-Down: 10 min easy spin
(Transition jog optional)

9. Tempo + Threshold Combo

Purpose: Combine mid-race control with strong finishing effort

Warm-Up: 15 min spin
Main Set: 40 min @ Zone 3 + 15 min @ Zone 4
Cool-Down: 10 min easy spin

10. Indoor Trainer Session

Purpose: Hit key intensities with high control and no coasting

Warm-Up: 15 min spin + 3 x 1 min build
Main Set: 6 x 6 min @ Zone 4 (3 min easy spin between)
Cool-Down: 10 min easy spin

Bonus Tip: Mix Indoor and Outdoor Sessions

Indoor trainers allow precise control over efforts and intervals, while outdoor rides develop handling skills and real-world adaptation. Incorporate both for a complete cycling program! Remember: Consistency, progressive overload and smart recovery are the keys to building your Ironman bike fitness.

Common Mistakes in Ironman Bike Training

Building a strong Ironman bike split takes more than just logging miles. The biggest training mistakes often come down to structure, pacing and poor recovery habits. Avoiding these will help you get the most from every key session.

• Training Without a Plan: Random rides lead to plateaus. You need structure to build endurance, strength and race-day control.

• Neglecting Intensity: Only riding long and easy misses the benefits of threshold and tempo sessions that sharpen race effort.

• Overdoing Brick Rides: Too many bricks lead to fatigue and poor bike quality. Prioritise fresh legs for your hardest sessions.

• Poor Nutrition Practice: Skipping race-day fueling strategies in training is a major mistake. Every long ride should double as a fueling rehearsal.

Smart, consistent execution of your bike sessions will prepare you to ride strong, fuel well and run off the bike with confidence.

FAQs: Ironman bike sessions

How many bike sessions per week for Ironman?

Most athletes train 3–4 bike sessions per week, balancing long rides, intervals and race simulation.

What FTP should I aim for for Ironman?

There’s no single target FTP. It depends on your background. However, most aim to race at around 65–75% of FTP for the Ironman distance. Zone 2 and low Zone 3 effort.

How important is bike nutrition practice?

Critical! You must train your gut to handle calories, fluids and electrolytes under exertion to avoid bonking or GI issues on race day.

FURTHER READING: BUILD BRICK STRENGTH

• Ironman Training: What Is Zone 2 / Endurance?

• Ironman Training: What Is Zone 3 / Tempo?

• Ironman Training: What Is Zone 4 / Threshold?

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

• Ironman Run Training: 10 Essential Sessions

• Ironman Swim Training: 10 Essential Sessions

• Ironman Training: Recovery Week

• Ironman: Beginner’s Guide

Final Thoughts

Mastering the Ironman bike leg requires patience, consistent effort and a well-planned, smart training structure. Incorporate these 10 carefully designed sessions into your routine to progressively build endurance, increase power and boost your confidence on the bike. Doing so will not only improve your cycling performance but also set you up for a strong and successful marathon run afterward.

Which of these key bike sessions will you focus on first to level up your Ironman 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.