After speaking with Robert Chung, I scoured Las Vegas looking for a section of road with a consistent grade, new pavement, and little traffic. I was fortunate to find a new subdivision under development that matched up perfectly with what I needed. The Google Earth image and profile below shows the course we used for our initial testing.
Getting Reliable Elevation Data
My first thought was to pull elevation data from an iPhone or Garmin. What I learned was that the GPS elevation data on a device like these are typically accurate to 3 to 40 meters depending on your access to satellites. This would not work.
Enter the Trimble R10 GNSS System
Ironically while looking for an option, I bumped into a surveyor while hiking. I asked him a number of questions about reliable GPS elevation data, and he recommended the Trimble R10 GNSS System. The accuracy, when connected, is +/- 5cm. I found a local supplier and rented one for the day to collect elevation data.
After getting familiar with the R10 and fighting with satellite connection in a low service area, I was able to collect reliable data points for the course.
Final Course Elevations - Time To Test
The final course elevations were set at 1,055.75 m and 1,080.13 m after averaging several measurements at each point. With elevation data in hand and the Chung Method in our back pocket, we needed one more piece before we started testing.
Check out Part 8 of our FLO Gravel Wheel Design Journey next week to learn about the new computer we used for testing and a report on our first tests.