Power meters · Public discussion

Unusually high PT pro readings

Started by jeremyb · · Last activity · 7 posts · 2,787 views

← Back to Power meters

Thread navigation

Jump through the discussion

Go to the original post, the replies on this page, or the latest preserved contribution.

01 / Original postUnusually high PT pro readingsjeremyb · 10 Apr 2004 02 / This pagePosts 1–7Page 1 of 1 · chronological order 03 / Latest replyPost #7velomanct · 31 Aug 2004

Thread details

What we know about this thread

Original section
Power meters
Published
10 April 2004
Last activity
31 August 2004
Original author
jeremyb
Posts
7
Discussion status
Public discussion
Total views
2,787
Views / 30 days
0
Topics
Power metersBottom bracketsCycling computersSpoke count

The navigation and discussion metadata provide context. Posts remain in their original chronological order.

Showing posts 1–7 of 7
Posts remain in their original chronological order.

Text size
  1. Original post
    jeremyb
    Archived post
    #1

    Hey guys---i hate asking this question---but i just set up my PT Pro and
    i went for a ride with my wireless bike computer (ciclosport 434) still
    on the bike and my powertap speed and distance was about twice what my
    old/correct computer was reading. If my Ciclosport read 16 mph the PT
    was reading like 32. Also my power numbers seemed off---i.e. too high. I
    treid switching to km just to see what happened and the numbers were
    even higher (which makes sense). I zeroed out the torque readings, i set
    the wheel circumference to 2096 (which is what the PT manual says is the
    circumference of a 700x23 tire).

    But then it gets weirder. I did a hard sprint and the speed readout on
    the PT went up and up to like 40-50 mph (obviously wrong) and then they
    dropped and equaled the readings from my ciclosport at 26-27 mph and the
    power output numbers dropped as well back to a normal amount like 300
    watts for 26 mph or so.

    What the heck is going on? I read on a forum not to tighten the zip ties
    down really tight (which i did) so i just went and took off all the zip
    ties and took my bike for a spin the parking lot and the numbers were
    still twice as normal.

    I've also now taken off the ciclosport computer just in case the computers were doing some sort of cross talk, but that didnt work.

    Also, i tried to adjust the position of the pickup sensor, to no avail.
    the only thing i havent tried was replacing the batteries.

    any help is much appreciated

    jeremyb

    Report
  2. ianbirlem
    Archived post
    #2

    my powertap speed and distance was about twice what my
    old/correct computer was reading. If my Ciclosport read 16 mph the PT was reading like 32.

    Hey Jeremy,
    See the posting above "Powertap recall?"
    http://www.cyclingforums.com/t129757.html
    Sounds like you have one of the bad hubs. Powertap has experienced some severe reliability problems and quality control issues over the years. So much so that the original manufacturer Tune went out of business (though there were probably other contributing factors). People say they have improved the hub's water sealing, but they clearly are still having problems. See the posting "Powertap still bad in the rain" also.

    Ian

    Report
  3. velomanct
    Archived post
    #3

    i have had my powertap read 5146 watts max, and 280mph in the downloaded screen. it rained on that ride for a bit.

    too bad, i wish i really did 5000watts

    Report
  4. beerco
    Archived post
    #4
    Quoted post said:

    Originally posted by jeremyb
    Hey guys---i hate asking this question---but i just set up my PT Pro and
    i went for a ride with my wireless bike computer (ciclosport 434) still
    on the bike and my powertap speed and distance was about twice what my
    old/correct computer was reading. If my Ciclosport read 16 mph the PT
    was reading like 32.
    jeremyb

    Contact Graber - there was a batch which had a bad reed switch/conditioning circuit design. Should be covered under warranty.

    Report
  5. mattv2099
    Archived post
    #5
    velomanct said:

    i have had my powertap read 5146 watts max, and 280mph in the downloaded screen. it rained on that ride for a bit.

    too bad, i wish i really did 5000watts


    I doubt you'd want to do that many watts!

    I bet your tire would disintegrate and your chain would explode and maybe your pedal axel would crumple and the grease in your bottom bracket would ignite.

    Or something like that.

    Report
  6. DeanC
    Archived post
    #6
    mattv2099 said:

    I doubt you'd want to do that many watts!

    I bet your tire would disintegrate and your chain would explode and maybe your pedal axel would crumple and the grease in your bottom bracket would ignite.

    Or something like that.

    Don't forget how embarassing it would be when the heat from your quads set your shorts on fire...

    Happy to help you see the bright side 😉,
    Dean

    Report
  7. velomanct
    Archived post
    #7
    mattv2099 said:

    I doubt you'd want to do that many watts!

    I bet your tire would disintegrate and your chain would explode and maybe your pedal axel would crumple and the grease in your bottom bracket would ignite.

    Or something like that.

    :eek:

    😄 technically i think the bike would hold up, as long as the rpms were above 100. the first thing to go would have to be the chain. (my chain which has 10,000 miles on it still holds up when i do hill accelerations from a stop at ~900 inch lbs torque(which is twice the peak i hit during a flat sprint). don't ask me how it hasn't broken yet, i feel it's time is due soon. i do keep it clean though).

    if not the chain, then i would guess the rear cog would fold. or if the wheel was weak, that might go. a friend of mine(big sprinter guy) broke spokes on his kyrsium wheel when sprinting up a 12% grade.

    i also heard a story of a local sprinter who broke his pedal axel in sprint. that would be ugly!

    Report

Keep exploring

Browse the sectionPower meters Return to CyclingForumsStart at the home page Search discussionsFind another thread

Active in the last 60 minutes

Active in this thread

0 users · 0 guests ·0 bots ·0 total

No signed-in users are active right now.

No known search crawlers active right now.