I was thinking this morning (while waiting for a conference call) about how to properly test for the aero qualities of a frame. The reason why I'm wondering this is because we have at this time an odd debate about various claims for aero.
-Apparently we're told that some frames are proven with a rider on top, yet others claim to be more aero... but with no rider testing it in the wind tunnel.
-Apparently we're told that some wind tunnel tests were performed with a dummy, others with a rider in motion.
-Apparently we're told that at certain yaw angles this frame performs better than that frame... but the problem here is we have no idea how likely a wind yaw angle actually exists on a course, and according to the National Weather Service Bureau (US), the yaw angles are measured at a certain height above the ground, which is not necessarily the height at which a frame sees wind.
-Apparently we're told that now wheels are designed specifically with the frame in mind.
-And that, despite all this, the rider is the greatest signifier in the aero qualities of a frame.
So here's my modest proposal:
1. Take a hill that is straight in its descent. At this time the steepness should be enough to allow for gravity to be significant, but it does not have to be terribly steep. The road ends into a flat section, again with no turns.
2. Each frame is equipped with the same handlebars, same stem type, same saddle, same crank type, and unless brakes are specific to the frame, same brakes. Same pedals. There is no chain. Rear and Front Derailleurs are attached as normal. Cabling is normal as well. The rider only has the ability to brake. Wheels are kept constant, tires are kept constant, tire pressure kept constant.
3. The rider is the same for all tests, same clothes, same helmet, same glasses, same set up. Tests are conducted within one week's time (see next point) to ensure minimal accounting for significant change in rider weight.
4. Rides are conducted within the same two hour time window on each day. This is to account for dramatic changes in the weather/wind which would affect the ride conditions between tests. All testing is conducted within one week in which the local weather at the site is predicted to be stable.
5. Rider starts at a marked line/point at the top of the hill. There is no pedaling, rather the rider is held at the start Track style, then released.
6. Rider descends in a straight line with feet on pedals in 3-9 position, same body position kept across all descents.
7. Each test is marked for the total length of descent until the rider comes to a complete stop. This distance is from a marked point at what is agreed to be the initial absolute 'bottom' of the hill.
This will possibly determine the true aero qualities of a frame in real world conditions... or as close as possible.
A. This would take a team of personell to perform properly. A team would need the bikes ready at the top of the hill. A second team would be available to catch the rider when they come to a complete stop (or are unable to maintain balance while moving in a straight line due to reduction in speed and maintenance of position on bicycle). A third team would need to immediately rush the rider back up to the top of the hill as fast as possible to get in as many frame tests within the two hour window, and immediately follow the rider back down the hill. A fourth person would need to record distances accurately.
B. I don't know of anyone really able to afford all the bikes frames in the world, so this would necessitate cooperation from the manufacturers. I have a feeling that many would hesitate to offer a frame for testing however as this would be a scenario which challenges marketing ability.
Thoughts? (Feel free to break it down, I'm genuinely fascinated by testing methods... scientific background/upbringing
|| Other projects in the works.