It could have been a lovely day. Set out on my usual 32 miles ride on the SRT here in Philly and it went just great (on the '76 Raleigh Pro Mk IV). "Oh, look how fast I am! Must really be in shape". After a few miles I knew I was in trouble as there's only one reason (other than drugs) for a step change in performance: strong tail wind. The SRT follows the Schuylkill River (surprise!!) so if there is wind, often from the west or northwest, you get it all, unmolested or abated by trees and buildings. So I had a fast trip out 16 miles then turned and, ugh, hit the headwind. 16 miles back to the car.

After about 45 minutes in the drops, grinding away at that and getting bored of staring at the shinny fork legs on the Raleigh (lovely British chrome though) I started wondering. Wondering things I would normally pay no attention to. So:

What say you physics majors? Is the wind like ying and yang in that the advantage of a tail wind is balanced by the disadvantage of the same wind on your face? Or is the advantage in speed and reduced effort of a tail wind wiped out by the increased work effort and drop in speed of the headwind on the way back? I am convinced that the 'free ride' of a down hill section does not make up for the added effort to get up the next equally tall hill. Net increase in energy. A hilly loop is much harder, albeit better exercise. A windy hilly circuit is, sometimes, enough to make you cry.

So how about headwinds and tailwinds? I rode a metric century out of St Michaels, MD - all flat but a wicked headwind off the bay for half of it. Even with long rest stops I was pretty wobbly when I got back to the car.