Originally Posted by
redlude97
If you consider the flow reattachment as a horizontal cross section of the wheel viewed from the side, a deeper wheel will have more of its "height" that has sufficient depth to reattach for such a wide tire, and as you add up/integrate those aero gains there is probably some optimal depth that would help. IIRC the only published data I've seen for gravel widths is the swissside data that shows ~2-5w
https://www.swissside.com/en-us/blogs/news/gravel-report
Thanks for that. The Swissside work does make it seem as though depth is critical (assuming same internal and external rim widths), just as we see on the road.
So the same optimization rules apply— get rim as close to tire width as possible, go as deep as possible— but what’s really interesting to me is that the effect of aero optimization are more consequential on gravel than the road in terms energy savings and loss simply because of the literal scale of the rubber. It reinforces my concerns arising from the realization that I tend to do longer (both time and distance) rides on the gravel bike than the road bike, and therefore, any gains have more time to accrue and become meaningful.
The weight piece is still a wildcard, if only because talking about a 1lbs variance is scary!