The Bike at Busselton: 90 Flat Kilometres Where the Wind Decides Everything

Ninety kilometres without a real climb

The bike leg at Busselton 70.3 is a single 90 km lap with just 103 m of total elevation gain. The maximum gradient recorded on GPX is 3.3%: there's no real climb, ever. Race reports describe the tarmac as good, and the organiser bills the course as one of the fastest in the world. The numbers back that up. But be careful: fast doesn't mean easy. Several reports, including from the full-distance race that uses the same road network, describe days when "flat" meant hours of uninterrupted work without a single metre of recovery. One athlete who raced the 2025 edition of the 70.3 sums it up well in his video title: he didn't get the time he wanted, on "the fastest course in Australia" of all places.

The real opponent: the wind

On flat coastal roads, wind is the variable that decides the race. The critical point is the "finger" sections (cul-de-sacs) in the tuart forest: you ride into one arm with a tailwind, turn at the end and find it straight in your face, and among the vegetation the gusts can shift direction unpredictably. There's no documented wind data specific to the 70.3, but reports from the full on the same roads flag very different conditions year to year: calm editions and editions with strong wind. You need to train to hold steady power into a headwind, solo, with no visual reference points: no group, no climb telling you how hard to push.

Aero position: the training almost everyone skips

With no descents to recover on and no climbs to switch muscle groups, you'll be on the aerobars practically the whole time: anywhere from 2h15 to over 3h15 depending on your level. Your neck, traps and lower back will give out before your watts do if you haven't prepared them. Concrete test: in the final 8 weeks, do at least two long rides staying in the aero position for 40-50 minute blocks without sitting up. If the position doesn't hold in training, it won't hold on race day. A virtual course simulator exists and it's a good way to understand just how monotonous the required effort is.

Pacing: the bill comes later

On a PB course the temptation is to push from the gun. Resist it. Hold your planned watts for the entire first half. With a tailwind you'll go fast almost for free: don't add power to "take advantage of it". Into the headwind, watch your watts, not your speed: low km/h into the wind is normal, the extra watts to compensate are the mistake you'll pay for on the half marathon. Rough benchmarks, our own estimates and not official data: 3:15 for a relaxed finisher, 2:50 for a mid-pack target, 2:30 for anyone aiming for a fast race, 2:15 for top age-groupers.

Gearing and equipment

With a maximum gradient of 3.3%, your cassette isn't a concern: aerodynamics is what counts. Deep-section wheels pay off here, but if you're light or not used to crosswinds, consider a mid-depth rim up front: in the forest fingers the gusts can catch you out. One practical tip from the race reports: soft flasks to refill at the aid stations, so you lose neither time nor equipment.

What to do now

Three concrete actions. One: schedule two long simulations in the aero position with steady-watt blocks, ideally on windy days. Two: decide your first-hour wattage now and write it somewhere you'll see it. Three: practise grabbing bottles on the move in training. The bike cut-off is 5h30 from your start: for almost everyone that's not an issue. The real issue is arriving in T2 with the legs to run 21 flat kilometres.