Bikes: Effect of tire width on rolling resistance

[Chalo]

AMuzi <a...@yellowjersey.org> wrote:
>
> landotter wrote:
> >
> > It's a shame, as ~30mm is just a great width tire for all sorts of
> > riding, but most all-round bikes come with miserable riding 35s in
> > gumwall--whose leaden ride the hipster bike shop guys usually blame on
> > the non-compliant aluminum frame. ;-)
>
> Have you ridden IRC Tandem 30s?

Those are the ones that are taller than they are wide, right?
Strange. The only other tire I have noticed that was taller than its
width would suggest was the Michelin Transworld City 700x47 I used for
a while. It had a definitely elliptical cross-section in the plane of
the wheel. On a wider rim like the Kris Holm 29er Muni rim, it might
have displayed the "triangular" shape that characterized some sport
motorcycle tires of the 1960s and '70s. Those were reputed to be
unsettled while riding in a straight line, but quick to hook up
solidly at a steep (non-bicycle-like) lean angle.

Chalo

[pholman50]

On Mar 30, 12:37*pm, Tom Reingold <nogli...@**********> wrote:
> I remember Jobst saying that rolling resistance decreases with tire
> width UNTIL you reach 28mm, and thereafter, rolling resistance goes
> up. I'm not sure if I remember this right. In any case, if it is true
> that below a certain width, rolling resistance goes up, why is this?
>
> Tom Reingold
> Maplewood, NJ

Another version is, for tires identical in every respect except width,
the deflection at the contact patch requires more energy as the
flattened chord is longer for a narrower tire (simple geometry). IOW,
the resisting torque required to flatten a longer contact patch is
higher. Restitution is normally stated as a % so the net % loss is a
bigger number for a smaller tire.

Above 28 mm, other factors overshadow this phenomenon.

Phil H