I Bike Power Meter

Discussion in 'Australia and New Zealand' started by SteveA, Apr 11, 2006.

  1. SteveA

    SteveA New Member

    Joined:
    Jul 15, 2004
    Messages:
    1,309
    Likes Received:
    0
    I came across this power meter http://www.ibikesports.com/techinfo.html
    at Performance Bike. Looking at the manual for it http://www.ibikesports.com/documents/instructionsataglance032006.pdf,
    makes me wonder why every maker of bike computers has not jumped on the same band wagon (assuming it gives a reasonably accurate reading).

    Physicists and engineers, please feel free to rip this piece of equipment and its technology to bits. I fact I will be bloody disappointed if you do not provide some critical comment.

    Steve(there must be room for another gadget on the handlebars)A
     
    Tags:


  2. Bleve

    Bleve Guest

    SteveA wrote:
    > I came across this power meter http://www.ibikesports.com/techinfo.html
    > at Performance Bike. Looking at the manual for it
    > http://www.ibikesports.com/documents/instructionsataglance032006.pdf,
    > makes me wonder why every maker of bike computers has not jumped on the
    > same band wagon (assuming it gives a reasonably accurate reading).
    >
    > Physicists and engineers, please feel free to rip this piece of
    > equipment and its technology to bits. I fact I will be bloody
    > disappointed if you do not provide some critical comment.


    it's working on air speed. How's your tyre pressure? How's your frame
    & wheels aerodynamics? How's the road surface? How're your bearings?
    Got an aero helmet on? 46cm bars? got a crosswind? etc etc

    I guess you're putting out ... oh, 230 watts. Close enough!
     
  3. TimC

    TimC Guest

    On 2006-04-11, SteveA (aka Bruce)
    was almost, but not quite, entirely unlike tea:
    >
    > I came across this power meter http://www.ibikesports.com/techinfo.html
    > at Performance Bike. Looking at the manual for it
    > http://www.ibikesports.com/documents/instructionsataglance032006.pdf,
    > makes me wonder why every maker of bike computers has not jumped on the
    > same band wagon (assuming it gives a reasonably accurate reading).


    Primarily because it must be so bloody expensive that there won't be a
    market for many companies to compete for it.

    > Physicists and engineers, please feel free to rip this piece of
    > equipment and its technology to bits. I fact I will be bloody
    > disappointed if you do not provide some critical comment.


    Hmmm, it probably uses pressure, temperature and windspeed to
    calculate how much air resistance you have. So it neglects the size
    of your body, whether you are in the drop bars at the time, how much
    friction you have in your chainline and tires, etc.

    I guess the setup procedure (go fast, coast, go down, slow down) would
    be to get the orientation right, so the accelarometer knows which way
    is up and which way is front.

    It's like my HRM -- it guesses how much kJ I've likely burnt, based
    only on my HR, weight and sex. That surely can't be too accurate?
    I'm not burning 20% more energy just because my resting HR today is
    10bpm higher than yesterday due to too much caffeine (wheeee, boinc,
    bounce, bounce, bounce!)?


    I wouldn't expect it to get within a factor of 2.

    However, still nifty. I wish I had a gradient meter on one of my
    computers :)

    --
    TimC
    "The application failed to fail"
     
  4. adam85

    adam85 Guest

    "TimC" <[email protected]> wrote in message
    > It's like my HRM -- it guesses how much kJ I've likely burnt, based
    > only on my HR, weight and sex. That surely can't be too accurate?


    Depends on whether you can default the sex value to zero, Tim :)

    Someone has stolen my mate's idea and put a power sensor in the bottom
    bracket...check it out...

    http://www.ergomo.net/

    Adam
     
  5. Andrew Price

    Andrew Price Guest

    SteveA wrote -

    > Steve(there must be room for another gadget on the handlebars)A


    I understand the next incarnation of a power meter will be a pressure plate
    between your shoe and cleat with a sender at the heel of the shoe - an Oz
    invention.

    Will have its own chest band to measure hr and the other usual cyclometer
    functions and obviously be moveable between any bike or trainer (wherever
    your shoes go...). Much less pain than an SRM or PowerTap and about half the
    cost.

    Should be a prototype around November I am told. Sidi are looking at
    selling shoes with the plate and sender pre-installed.

    regards, andrew
     
  6. SteveA

    SteveA New Member

    Joined:
    Jul 15, 2004
    Messages:
    1,309
    Likes Received:
    0
    The price I saw was US$350 which is as near as buggery to A$500 - a fair bit cheaper than other power meters.

    That is the price, not the cost of production. I have an digital anenometer/thermometer/barometer/altimeter which cost me A$99. The quality is probably about the same as in this power meter. A basic el cheapo computer can be had for about $20. Add a gradient sensor (use the altimeter?) and you would have to be able to get them to market for less than A$150. (Intellectual property licence costs aside).

    Power Tap from the same source is US$999. I expect the price of the I Bike thingy is probably set by reference to the real power meters' prices than cost of production.

    That's' why I posed the question that linked accuracy to other makers bringing out something similar. :)

    SteveA
     
  7. suzyj

    suzyj New Member

    Joined:
    Mar 22, 2004
    Messages:
    704
    Likes Received:
    0
    Adam85 wrote:

    > Someone has stolen my mate's idea and put a power sensor in
    > the bottom bracket...check it out...

    > http://www.ergomo.net/

    Cool - now you can know within 0.5% how much power your left leg is putting out, and still have no idea about the right one :)

    Cheers,

    Suzy
     
Loading...
Loading...