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Course Rankings: How the Score Is Calculated
When you pick a course, "is it fast" is usually something you heard from someone else. People say Kona is hard. People say Penghu is flat. Both are half right: Kona's terrain is not actually that hard, the wind and the heat are. Penghu is flat, but the April monsoon will make you feel like you are climbing.
The speed score turns those impressions into a number you can compare.
How is the score defined?
Every course starts at 100. Four deductions come off, with a floor of 30:
| Factor | Method | Cap |
|---|---|---|
| Terrain | Climb density (meters of elevation gain per km) × 1.8 | −30 |
| Technical | Effective turn density × 0.13 | −12 |
| Heat | Race-day temperature: × 1.2 per degree above 24°C; × 0.5 per degree below 10°C | −14 |
| Wind | Typical race-day wind speed (m/s) × 2.2 | −16 |
100 means ideal conditions for speed: flat, cool, no wind, few turns. 90 and above is a Very fast course, 80 to 89 Fast, 70 to 79 Neutral, 60 to 69 Hard, below 60 Very hard.
The four caps are different on purpose. Terrain carries the most weight of the four, because elevation gain is a real energy cost that no position or equipment can get you out of. Technical has the lowest cap, because the slowdown from turns adds up a few seconds at a time, and it is hard for that alone to make a course a hard one.
What does each factor measure?
Terrain uses climb density, not total elevation gain. 1,800 m of climbing over 180 km and 900 m over 90 km are both 10 m/km, so they lose the same points. That is what lets 226 and 113 courses sit in the same table.
Technical counts only "effective turns": only the part of a segment where the direction changes by more than 25 degrees counts, and the natural curvature of a country road is not deducted. A U-turn is 180 degrees in one go, so multi-lap city courses with U-turns will score higher on Technical. Challenge Roth taught us this rule: an early version counted every natural bend on the German country roads, and Roth lost 15 points on Technical, which did not match its reputation as a fast course at all. After changing it to count only the turns that need braking, Roth's Technical deduction dropped to 3.5.
Heat and Wind use the five-year average of measured weather for the same period as the race's calendar slot, taken from meteorological reanalysis data, regardless of how many editions the race has held. So a brand new race has a complete score on day one, as long as the date is known. Once you pick the exact race date in the Console, these two factors switch to that day's forecast and the score is recalculated.
One thing about the Heat deduction has to be said plainly: at the same power, hot air is less dense, so you actually ride slightly faster. The cost of heat is physiological: the power you can hold drops. That is why heat does not go into the finish-time breakdown, only into this score.
Seven courses as examples
Look at this chart and you will see that courses sitting around 70 points can lose their points for completely different reasons. Taitung 226 loses some to Terrain and some to Wind. Kenting loses almost all of it to Wind. The same athlete racing these two needs to train different things: one calls for power control on rolling roads, the other for headwind position and mindset.
What is this score not?
It compares how easy a course is to ride fast, not how fast you will go. Your finish time comes from your power plan. The score answers one question: with the same ability, on which course is it easier to ride a good result.
It also has known limits. The weather is an average from a single location over the bike-leg time window, which underestimates locally strong wind sections. The crosswind on the way to Hawi at Kona is the classic example: the real wind is worse than the score makes it look. I plan to fix this with multi-point sampling and uploaded ride files, and when it is fixed I will update it here.
The rankings themselves are here: Course rankings, filterable by region and month. The verification badge next to a score shows where the route came from: official route, ride-verified, or a public community route pending review.
Picking a course still comes down to your own strengths. The score tells you what the course demands. Whether you have it, you already know.
