Jan,
Agreed on the practical practice side, but I am still curious about the med 
hi to hi pressure phenomena.
If I understand correctly, you say that from nominal to very high pressure, 
losses in the tire itself decrease. But from nominal to moderately high 
pressures, suspension losses increase more and overwhelm the reduction in 
losses in the tire so that the total resistance increases. However from 
moderately high to very high pressure total resistance decreases. Do you 
have a theory / explanation for that? What component of the total 
resistance goes down with increasing pressure in that medium to very high 
pressure regime? 
Though it's not significant as a practical matter, somehow the engineer in 
me still wants to know.

On Sunday, January 5, 2014 6:50:27 PM UTC-8, Jan Heine wrote:
>
>
>
> On Sunday, January 5, 2014 5:45:23 PM UTC-8, ted wrote:
>>
>> If I read that right, you are saying that your data shows a local maxima 
>> at medium-high pressure with lower losses at tire pressures both above and 
>> below that point. Is that really what you mean to be saying?
>>
>
> Yes, that is what we found. (There is a second maximum at very low 
> pressures, like below 40 psi for a 25 mm tire). As you point out, the 
> differences, while statistically significant (we had so much data that it 
> was easy to filter out the noise), don't really matter in real life. 
>
> "Just ride" really is a good way to think about tire pressure. It's nice 
> to know that obsessing about tire pressure doesn't gain you anything. I now 
> inflate my Grand Bois Hetres to about 45 psi, and then ride them for a few 
> months, until they start washing out under hard cornering, at which point I 
> inflate them again. It's nice not to worry about tire pressure more than a 
> few times a year. I do reduce the pressure if we are heading over long, 
> rough gravel sections, but then I hardly ever re-inflate them even if we 
> are riding for hundreds of miles on pavement thereafter.
>
> Jan Heine
> Editor
> Bicycle Quarterly
> www.bikequarterly.com
>
> Follow our blog at www.janheine.wordpress.com
>

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