Re: Analytical Nonsense



A

Andy Coggan

Guest
On Dec 2, 10:05 pm, MagillaGorilla <[email protected]> wrote:

> 1) The power output is not constant. It's lower in a turn.


Usually, but not always, especially for an experienced rider on a
larger track.

> 2) The coefficient of friction/rolling resistance increases in a turn.


True.

> 3) Velocity has a vector component in physics equations that is being
> constantly changed throughout a turn. This is inefficient and creates a
> loss in energy. Energy to change the vector component of velociity is
> lost in friction that is otherwiise conserved in a straightaway.


True, but the effects of tire scrub on rolling resistance appear to be
minimal, because the Crr as measured on a velodrome is quite similar
to that measured on a comparable surface when traveling in a straight
line. For example, after correcting for the increase in normal force
in the turns, the Crr of ADT (which isn't the smoothest track in the
world) is 0.0028 for a rider using 20 mm Veloflex Record clincher
tires and latex tubes, inflated to 130 psi. This is nearly identical
to what others have obtained when, e.g., testing on a rotating drum,
with the minimal difference probably due to the very small steering
angle.

> 4) Aerodynamic drag is increased in a turn, not because of increased
> speed but because the rider's direction of travel through a fluid is not
> as efficient in a turn as it is in a straightaway. There is more
> surface area on a rider's body hitting airflow in a turn.


On the contrary, an effective crosswind (such as is encountered in the
turn on a track) can actually reduce your CdA.

> If you were to do a test with a rider asked to ride a 10 km time trial
> on a straight road vs. a rider doing 10k in a perfect oval velodrome,
> the rider going straight would always win. According to you the rider
> going in a circle would win. You are wrong.


No, you are wrong, for one very simple reason: even if all other
aspects are held constant, the center of resistance of the rider on
the velodrome wouldn't have traveled the full 10 km.

Andy Coggan