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Old 07-24-2012, 07:12 PM   #5 (permalink)
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Originally Posted by woodstock74 View Post
What's the consensus, is it the reduction of the volume of air that passes through them that is cut off/reduced (i.e., closing up the spokes and sealing them), or that they are flat (which does the same of course, but with the added benefit that they are flush to the tire) that is responsible for the drag the reduction?

I'm contemplating modifying my existing hubcaps by simply filling in the "spokes" and insuring no gaps between the hubcap and the tire, but this won't make them flush.
I've yet to read a complete discussion on wheel covers.
Observations have been reported and recommendations.
*An open wheel has no surface with which to 'support' airflow,so a solid surface is needed.
*A slightly convex disc won't 'tin-can',is extremely rigid for it's mass,and has a measurable drag advantage over a flat disc.
*Brake cooling should not be ignored,however solid 'MOON' style wheels have shown to be no disadvantage for many members including myself.
*The knock-on style covers are noisy and eventually come off.I've written them off.
* I was able to scrounge up a set of covers from a 1975 Buick Electra.They are absolutely 'silent,' securely hold to the wheel,and have modest ventilation for brake cooling.
*Many members have found covers which stay firmly attached which can be modified aerodynamically.
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