Aerodynamics stupid

The last few months I've been paying attention to my average speed in relation to wind and the clothing I wear. Even though it would seem obvious, there's nothing quite like first hand experience to drive the point home. What I've noticed is that if I wear a winter riding jacket, my average speed for my usual lunch ride is 1mph slower. One might ask, "How do you know?"

I don't use a power meter, so there isn't definitive proof with hard numbers. What I do notice is the sections where I have the highest split times, are 1-2mph slower when I wear jackets versus long sleeve jersey. In contrast, when the temperature is above 70 and the wind is 15-20mph, I can still average 19mph for 21miles. The main reason is the amount of drag. In warm weather, I wear bib shorts and short sleeve jersey. Below 50F, I wear either a long sleeve jersey or pearl izumi jacket. Basically, when it's sunny I wear long sleeve jersey and cloudy days I wear the jacket for a little extra warmth.

So this got me thinking about bike frames and value. My giant avail advance has a aero seat post and seat tube. The down tube is also aero, though not as aero has Specialized Venge, time trial bikes or other aero road bikes costing 5-10K. I paid just under 2K for the avail, whereas the equivalent bike from Trek and Specialized would run in the 4-5K range.

Within old school bike purists, many prefer steel or titanium frames. The thing is, metal frames generally are tubes, which isn't the best for aerodynamics. My Trek mountain bike has oval steel tubes, but it's not for aerodynamics. They're thick heavy tubes made to take a beating.

Is it possible to make an aero frame using titanium or steel? I don't know, since I'm not a frame builder and don't know the first thing about it.