UPHILL/DOWNHILL CALIBRATION DATA
In 1993 seven riders gathered in Birmingham, Alabama, to measure the course of the US Men’s Olympic Marathon Trials. The start was east of town at a higher elevation than was the main part of the course, separated from the finish by about 15 km. We wanted a calibration course at each end, one near the start and one near the finish.
The finish was downtown and a flat 300 meters was laid out.
At the start, everything was either high-traffic or had a hill. We elected to use a little-traveled straight side road that had a hill. It was later certified as AL03038BDC.
Checking with Google Earth gives a rise/drop of about 11 meters (drop = ±36 m/km) over the 300 meters of the course.
Precal was at 7:30 AM at 77F. The seven riders averaged 3347.66 counts on the 300 meters (11158.9 counts/km). The average downhill ride was 1.54 counts greater than the average uphill ride, or 5.13 counts per kilometer.
Postcal was at 10:15 AM, at 89F. The seven riders averaged 3345.93 meters on the flat 300 meters (11153.10 counts/km). The rides going east differed from the rides going west by 0.28 counts, or 0.93 counts per kilometer.
The measurement file is available in Excel for the asking, as is the complete measurement report. Contact me if you want either.