ibike pro power meter

On Sep 6, 3:11*pm, James wrote:
On Sep 6, 6:39*pm, yirgster wrote:

ibike pro power meter.http://www.ibikesports.com/products_ipro.html

Any opinions on this? *I'm thinking of getting one.

It measures aerodynamic and barometric pressure. *I guess this is to
measure your effective air speed.

It measures time and distance.

It measures the road gradient.

It doesn't measure bearing, drive train or tire loses.

So my guess is that it assumes an aerodynamic drag coefficient (or you
program one in), and it then estimates power to overcome the
aerodynamic drag and change in altitude.

Whether or not it takes into account acceleration is unclear.

Awhile back there was a study that showed the Ibike was within 5% as
accurate as the SRM. Sorry but I forget where this was. In my mind
the Ibike is accurate enough.


I'm not convinced that it would be particularly accurate compared to a
device that measures mechanical forces.

Regards,
James.

On 9/7/2010 2:46 PM, Randall wrote:

Awhile back there was a study that showed the Ibike was within 5% as
accurate as the SRM. Sorry but I forget where this was. In my mind
the Ibike is accurate enough.

The issue isn't how close it is on average to a SRM (or PT or Quarq).
The issue is "under which conditions isn't it?" Under steady conditions
almost anything is good enough and the proportion of steady state riding
will influence numbers like that 5% you quote. However, the value of a
more precise and accurate PM shows when power is very variable, or when
you're trying to measure small changes with high precision.

That said, not everyone needs a PM that handles extreme conditions. For
them the iBike could be a perfectly appropriate purchase. One coach
calls the iBike a "gateway drug." Some buy it then move on to the hard
stuff. Others just puff away at a low level in perfect bliss.

On Sep 7, 6:24*pm, Fred on a stick
wrote:

The issue isn't how close it is on average to a SRM (or PT or Quarq).
The issue is "under which conditions isn't it?"

Repeatability is actually more important (remember that repeatability
and accuracy aren't the same thing) . Once you set up a power meter,
you want consistent results for the same 'effort' under the same
conditions. If the meter shows 5% variations from day to day under the
same conditions (weather and terrain), all it will do is confuse you.
It sounds like the ibike will do just that if you don't calibrate it
for each ride - a real PITA.