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Old 03-19-2018, 01:13 AM   #37 (permalink)
California98Civic
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Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
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Quote:
Originally Posted by oldtamiyaphile View Post
Bigger tyre = lower RR. Car or bike, doesn't matter. ...
Ok. I think I get it now. I did not know the difference between rr force and the coefficient. Learn something every day. But, don't hate me, even the graph you posted is a little ambiguous. While the general trend of larger tire, less rolling resistance is clear, it is not without noise. For example your chart suggests that I IMPROVED my rolling resistance by going DOWN in size from a 185/65-R14 to a 175/70-R13. That is what I actually did and possibly went from a 12.0 Crr to an 11.5 Crr. Unless, again, I don't get it.

So that settles the general picture for rolling resistance, but the thread title is about width and FE and everyokne seems to agree there are lots of variables and that even if a given wider tire provides better RR other factors like weight and aerodynamics might overwhelm that benefit and produce lower FE anyway.
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.




Last edited by California98Civic; 03-19-2018 at 01:14 AM.. Reason: Typos
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