This monster of a challenge is nothing like a sprint or olympic distance triathlon. It takes careful training and a strong race day plan to avoid those common pitfalls in the Ironman bike leg…

Ironman bike

1. Smart Snacking

During the bike section of an Ironman you will burn between 3,000 and 5,000 calories, which makes regular snacking vital in order to maintain energy levels. The easier it is to grab a snack, the more likely you are to do it. In the middle of a long tough ride you won’t feel like digging gels or bars out of a deep back pocket so keep them on your bike where you can access them easily. Bento boxes are a good idea (Velcro snack boxes that attach to your top tube) or you could try filling a bike bottle with energy gels.

Scicon fuel Bag


2. Go Aero

On a flat road, aerodynamic drag is by far the greatest barrier to a cyclist’s speed, accounting for 70 to 90 per cent of the resistance felt when pedaling. Your bike and more importantly your body position both make a big difference to this. But how do you know if you’re aerodynamic or not? Recently, developed the ability to predict your drag coefficient from the measurements of your bike and other details such as your weight, type of bike, height and power output. You’ll need a power meter, but it’s still a viable alternative to forking out £1000 on a wind-tunnel session.

Ironman bike

3. Power Up

Functional Threshold Power or FTP refers to the highest average power in watts that you can ride for an hour. It’s a classic measure of cycling fitness and it’s particularly relevant to endurance events such as triathlons. You can test yours out by jumping on a Watt Bike or riding a 20 minute time trial using a power meter. After you’ve done this multiply your average power for the minute test by 95 per cent – this gives a good estimate of your current FTP. The beauty of FTP is that it’s very trainable. A good sample workout would be 3 x 15mins at 90 per cent of your FTP with 60 second recoveries.

4. Keep it real

Before doing an Ironman it’s important to set realistic data driven goals. This will help you stay mentally strong because you are less likely to feel like you’re failing. Testing your CSS swim pace (as mentioned above) will give you a good idea of your swim potential – aim for 85-90 per cent of CSS for an Ironman swim or slightly faster if you’re wearing a wetsuit. On the bike aim for 68 to 78 per cent of your Functional Threshold Power or for a more accurate forecast try using On the run providing you’ve ridden sensibly, you should aim to run five to 10 per cent slower than your typical long run training pace.

5. Weigh your fuel

It has been proved time and again in scientific research that measuring your carbohydrate intake will improve your chances of success in an Ironman, says Dr Kevin Currell, Performance Nutritionist at the English Institute of Sport. He advises 60 to 90 grams of simple carbohydrates per hour to improve your performance. Estimate how long you’ll take to complete the Ironman and then look at the labels of your gels and bars to work out how many you’ll need. Aim to consume 20-30 grams of carbohydrate roughly every 20 minutes and don’t forget to take a couple of spares, just in case.

WORDS: Phil Mosley

Check out our aero tips here…