My Ironman Race Strategy: Why I Lock the First 60km of the Bike to Zone 2

The bike rule: Zone 2 only for the first 60km

My one non-negotiable rule on the Ironman bike is that the first 60km stays in Zone 2. No exceptions. Not on a tailwind, not in a fast group, not because I feel fresh. Heart rate is the gate, not perceived effort, because in the first hour out of T1 my legs always lie to me - the swim flushes me with adrenaline and the bike feels like I am barely working.

The reason for the 60km cap is mechanical, not motivational. Every watt I overspend in the first two hours is a watt I will not have between hour five and the marathon. The aerobic system can carry me at Zone 2 for an entire Ironman day. Lift the intensity by even one zone too early and I am drawing on glycogen I needed for the back half of the bike and the first hour of the run. By the time I notice the cost, it is on the run, and there is no way to unspend it.

What "Zone 2" actually means in numbers for me is set by my lactate and FTP testing, not a Garmin estimate - where my Zone 2 numbers come from walks through the field test I use to anchor the band. I lock it to heart rate on race day because power can spike on short hills without the average shifting much; HR is the slower, more honest signal that I have crossed out of base intensity.

The run rule: cap pace in the first 5km

The second rule is for the first 5km of the marathon. After 180km on the bike my legs should not feel good - but they always do, for about 10 minutes. Adrenaline plus the relief of being off the saddle plus the fresh-feeling-by-comparison muscles trick me into running 30 to 45 seconds per mile faster than goal pace. Every time. So I plan against the trick rather than negotiate with it in the moment.

My cap is 9:30/mi for the first 5km, regardless of how good I feel. I check it by heart rate, not the pace number on the watch, because pace will drift fast with adrenaline and the watch updates on a delay. If HR is above my aerobic ceiling I slow down even if the pace screen says I am right on plan. The cost of running the first 5km 30 seconds too slow is nothing. The cost of running it 30 seconds too fast is a death-march from kilometre 25 onward.

The pre-race fueling cue: one chew before the swim

One Open Blocks chew (carb chew) goes in my mouth immediately before the swim start. That is the only piece of pre-race fueling I treat as non-negotiable on top of breakfast. The reason is that the swim is the leg I cannot fuel during. By the time I am out of the water and onto the bike, anywhere from 50 to 70 minutes have passed since my last input.

The single chew is not enough calories to matter for the day's total. What it does is give me a measurable, recent carb baseline that survives the swim. I exit T1 with carbs already on board rather than starting the bike from empty and chasing the deficit for the next two hours. It is a small cue with a specific job: set the floor.

The mistake I'm correcting

All of the above exists because of one prior race where I went out too hot in the first kilometres and paid for it on the back half. I am not going to litigate it here - the short version is the front end felt easy, I let the pace run, and the second half was a long, ugly lesson in what happens when you spend energy you do not have.

"No NYC nonsense" is the shorthand I use with myself for it on race day. When the bike feels easy in the first hour, when the run feels light in the first 10 minutes, when a group is pulling away and the legs say go - that phrase is the cue to hold the cap. The entire race plan above is built to make sure I do not repeat that one specific mistake.

What this plan isn't

This is not a coaching plan. The Zone 2 ceiling, the pace cap, the chew - all three are calibrated to my heart rate zones, my lactate response, and my prior race history. The numbers should not be copied. The structure - cap the early bike, cap the early run, take a single recent-carb cue into the swim - might be portable; the actual values are not.

If you want to set your own equivalent, start with your own threshold data. The way I do that is in the lactate testing protocol and the FTP-based cycling zones posts. Build your zones from your own tests, then write your own version of these three rules against the mistake you are most likely to make on race day. Mine is going out too hot. Yours might not be.