Suspension losses

Good article from Jan Heine on benefits of wider, softer tires for absorbing vibration and lessening suspension losses:
https://www.renehersecycles.com/the-missing-link-suspension-losses/
At the time the rumble strip test was published, I expressed some skepticism because its roughness is fundamentally different than the random roughness of either a rough road or a gravel road. In particular, the rumble strip is all "negative," cut into the smooth surface, while rough or gravel roads have both "negative" holes plus "positive" patches or rocks that protrude above the surface. One practical difference is that when dealing with only "negative" roughness, higher speeds reduce losses. The opposite is true with "positive" roughness.
But I suppose for demonstrating the fundamental effect, the consistency of the rumbles is useful. And the measurements seem valid as long as the test speed is also consistent.
BTW, Jobst Brandt is mentioned in the article. I recall that in discussing rolling resistance here, he insisted that "rolling resistance" should be defined _only_ as the losses generated by tire rubber's hysteresis. I disagreed, because that implied that solid rubber tires a la 1880, or near infinite tire pressure, or even metal rims with no tire, would be best. Anyone who has ridden an antique solid tire "safety" bike knows how slow those tires were.
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- Frank Krygowski