Busselton is one of the flattest 70.3 bike courses in the country, which means almost no coasting and almost no natural recovery. Constant pedalling holds power output high for the full 90km, and steady high output is a steady high carbohydrate burn.
Add the coastal wind and an exposed run and you have a course that rewards a disciplined, boring, on-the-clock fuelling plan far more than it rewards a hard first 30km.
What the race demands
Distance
1.9km swim, 90km bike, 21.1km run
Conditions
Flat, exposed and frequently windy coastal Western Australia
Main risk
No freewheeling, so carbohydrate burn stays high all bike leg
Second risk
Wind raising the energy cost of holding target power
Carbohydrate and sodium targets
- Bike leg: 70 to 90g of carbohydrate per hour from a dual-carb source
- Run leg: 60 to 80g of carbohydrate per hour, taken in small frequent doses
- Sodium: 500 to 1,000mg per hour, higher for salty and heavy sweaters
- Fluid: set by your measured sweat rate rather than thirst
HYDRAX CORE delivers 85g of dual-carb fuel and 980mg of sodium per serve, so hitting the numbers above is arithmetic rather than guesswork. HYDRAX PRIMER covers the pre-race window with 29g of carbohydrate and 1,313mg of sodium. Run the free fuelling strategy tool to convert these ranges into your own per-hour numbers.
Rehearse the plan in training, then race it. Order now, ships Australia-wide.
Race week and race day timeline
2 days out
Raise carbohydrate intake, drop fibre and anything unfamiliar.
Race morning, 3 hours out
Rehearsed carbohydrate breakfast at 1 to 2g per kg with sodium in your fluid.
25 to 40 minutes pre-swim
One serve of PRIMER: 29g of carbohydrate and 1,313mg of sodium before the swim blackout.
Bike, 90km
Flat and fast means no soft-pedal moments, so set a timer and fuel every 15 to 20 minutes without waiting for a natural break.
Run, 21.1km
Keep carbohydrate coming in small doses from the first aid station. The half marathon is won by the athlete who fuelled the bike properly.
Frequently asked questions
How many carbs per hour on a flat 70.3 bike course?
Flat courses keep power output constant, so carbohydrate demand stays high for the full 90km. Target 70 to 90g per hour from a dual-carb source and fuel on a timer rather than waiting for a break in effort.
How much sodium do I need at 70.3 Busselton?
Most athletes land between 500 and 1,000mg per hour. Wind can mask sweat losses by cooling your skin quickly, so measure your sweat rate rather than judging by how dry you feel.
What should I take before the swim?
A pre-race serve 25 to 40 minutes before the start. HYDRAX PRIMER delivers 29g of carbohydrate and 1,313mg of sodium so you begin the bike already fuelled.
How do I stop the run falling apart?
Fuel the bike to plan, pace the bike to trained effort, and start the run with small frequent carbohydrate doses instead of waiting for the first sign of trouble.
Keep reading
- Ironman 70.3 nutrition guide
- Full Ironman nutrition guide
- Carbs per hour for Ironman
- Triathlon time calculator
- Measure your sweat rate
- Shop the HYDRAX kit
Disclaimer: This page is general information for healthy adult athletes and is not medical, dietetic or coaching advice. Individual carbohydrate, fluid and sodium requirements vary with body weight, sweat rate, conditions and health status. Speak with your doctor, sports physician or an accredited sports dietitian before changing your nutrition or supplement routine, rehearse any fuelling plan in training before race day, and always follow the directions and warnings on the product label.