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From: Frank Krygowski <frkrygow@sbcglobal.net>
Newsgroups: rec.bicycles.tech
Subject: Suspension losses
Date: Wed, 1 Jan 2025 12:08:00 -0500
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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.

-- 
- Frank Krygowski