Windtunnel time...

The opportunity presented itself to do a little "wind-tunnel time" this week. I have never done that before, so was quite interested in having a go! I did not know we actually had one, and as it turned out it was a bit on the basic side! That does not mean it is necessarily any less accurate, but I did adjust my expectations somewhat. I am a bit of a science-y sort of guy, and have spent a fair proportion of my life in university (not that I have actually put that to much use). I have also been involved in research - both sides (the "researcher" and the "guinea pig"). So I like to think I have a fair understanding of what goes on and what can actually be taken out of the lab in practical terms. From what I have seen and read, science is not nearly as exact as they would have you believe, and there is usually some blaringly impracticality in the study that makes the results a lot less useful than you would like. Sports science has to be one of the worst! So much individual variation, and what athlete of reasonable ability wants to do exactly what the sports scientist wants them to! Even though I like testing and experimenting, I am a little dubious, or shall I say cautious on results...

I have experimented with position and aerodynamics a fair amount over the years. My feeling was that if you can go faster in a more aero position with less effort, why not do that! My standard test was while doing hill reps, and on the descent (preferably a down hill you don't need to brake on), start at the same speed each time and then try to get the best maximum speed with different body positions. The highest speed (all other things being pretty much equal) should in my theory be from the more aerodynamic position. I knew that for me being low was best. Getting low on the drops was better than the standard position on the aerobars (but not quite so comfortable for a longer period). I also felt I could make myself a little more aero, by sort of dropping the shoulders a bit and "feeling" more aero - without spending a page explaining that...

Back the the wind tunnel - basically a couple of very large fans blowing at you and your bike, that is attached via the back wheel to some measuring stuff. The measuring stuff is suppose to give a drag number - which is basically your resistance to wind. While riding your bikes, anything over 30kph, most of your effort on the flat is overcoming wind resistance. So if you can lower your wind resistance, you can either co faster with the same effort, or go the same speed with less effort. So to cut a long story a bit shorter, trying different positions and equipment in the wind tunnel to find optimal positions and equipment to minimise your wind resistance should make you faster! I have spent a good amount of time investigating these aspects already, along with bike fit, so it is certainly not a new area for me.

I was hoping to test wheels and a whole heap of different set-up options, but after seeing the rig, decided that was not actually going to give much useful data - the main reason being that the front wheel was stationary. I started with what I thought was a pretty good position, and set this as my baseline. The brief summary is that pretty much everything I tried was slower! While there was no ground break revolutionary new-fangled position that emerged, it was good to know that what I thought was right, was shown up in the data. Watching others being tested was also interesting, not only in what they tested, but how things changed while they were tested. Some were trying to put in solid efforts while being tested and the variation in readings within each test run (due to quite large body movements etc) was far greater than between different positions and equipment. Items that are more aerodynamic on their own were not necessarily better in the complete cyclist-bike system. One person was more aero in a standard helmet, than with an aero helmet on. Another used the same helmet in two runs, one with a visor on (which should be more aero) and one without. However the trial on the helmet without the visor gave a better drag figure. I think this is where you need to be a little careful, as it is easy to say "well the test show a visor is less aero - so we won't use one". If you actually investigate a little further you can explain the difference - and in this case the helmet straps were set up differently, and the helmet sat differently on the head. So in fact the test probably showed that you need to wear the gear better rather than get better gear!

What did my trials show? Having just got the actual data - the aero helmets were faster (significantly) for me - I tried two. There was a small difference between the two, but not enough for me to say they are different. Drink bottles behind the seat increased drag - but not very much, less than I would have thought. Putting my head down with the aero helmet on (so the tail was sticking up) increased drag significantly. Raising the stem up was less aero, as was making the elbow pads wider - going higher was worse than going wider. I tried the aerobars pointing up higher (old school rather than Landis extreme) - and that was not as aero - which was probably a little surprising, as I thought that would be quite a good position, but I don't find it that comfortable at the moment. The last run I did was in my standard baseline position, but trying to make myself more aerodynamic - rather than in a standard relaxed position. This did improve my drag figure - quite a bit! My drag was almost 10% less, which is a huge savings! I would probably have to test the power output difference to see if that was worthwhile though, as I am not sure I could pedal hard in that position for a long time. So all up it was an interesting process, mostly as I expected, but a few little bits of information that were not quite as expected. Perhaps a bit more study on the photo's will also be useful...