The comment Lemuroid makes upthread about aero problems with bike is true.
An example: At SAE we tried to cut down on the 'fan' action of the large bicycle type wheel, thinking it was impeding maximum acceleration downhill (The Chute).
It was hard to get the large spoke covers to fit tight and not fall off, and to not mess up the balance of the wheels.
The bigger problem was side winds during free roll (especially at The Chute - breezes coming up the hillside from Panther Hollow), which would push the bike around (sideways), due the large side surface area - when wheel covers were used.
Thus we had to make a decision on using covers, or not - based on the wind conditions on Race Day for our specific heat. This is not something to decide at the last minute (i.e., we needed to multiple sets of ready-to-go (and expensive) racing bike wheels + tires/hubs/bearings, etc., ready to be changed at a moments notice
* "I love the smell of solvents at Free Roll. It smells like......victory".
* "I'm loosing my mind, but I don't seem to miss it much."