Stage 18 results and Stage 19 prediction ...

Italian Andrea Guardini won Stage 18 of the Giro d'Italia today, just beating out Mark Cavendish of Great Britain.  Below is a comparison of the winning time with our prediction, followed by Guardini's average speed for the 139-km (86.4-mile) stage.

• Stage 18:  3h 00' 52" (actual), 3h 11' 49" (prediction), 10' 57" slow (6.05% error)
• Stage 18:  12.8 m/s (28.7 mph)

I'll take a 6% error on a race I just started modeling this year, and at the end of the race at that.  As  I have noted in previous posts, modeling these cycling stages is not only a great deal of fun, it is hard.  If my model is too simple, I am glossing over complexities that influence a race.  If my model is too complicated, I am making too many a priori assumptions, many of which are certain to be incorrect in the actual race.

Okay, on to Stage 19, which looks to be a brutal mountain stage.  Starting in the north Italian city of Treviso, the stage ends 198 km (123 miles) later in Alpe di Pamepago, which is in the heart of the Dolomites.  Beginning at just 15-m (49-ft) elevation, cyclists will reach the 2047-m (6716-ft or 1.27-mile) peak at Passo Manghen after 123.3 km (76.6 miles) of biking.  The final 8 km (5 miles) will make for a grueling uphill to the finish line.  Here is our prediction:

• Stage 19:  5h 43' 12" (prediction)

I hope cyclists have enough fuel in the tank to make it up the final climb fast enough that our prediction is not too fast!