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Topeak computer conundrum

pinnopinno Posts: 38,242
edited September 2012 in Workshop
Just replaced the battery on my cheapy Topeak computer and I do not know what the calibration number for the thing is. If you own a Topeak and you actually kept the instruction/fitting booklet unlike me, please tell me what the calibration number is for a 700x23 and a 700x25c tyre. Ta.
I used a Blackburn chart 'measure the rolling distance' and came up with an entry of 2105. I was very happy cycling along at an average 28mph but unfortunately the suspension of reality has to stop. :(
S - The Brazilian beach volleyball team
W - Wiggle Honda

"This year will be harder than last year. But that is good news; this year will be easier than next year." President of Abyssinia's annual address to the nation.

Posts

  • can you not do the rolling tyre test? chalk mark on the tyre and path, get on it and ride slowly counting the revolutions (much easier with a helper) then measure the distance and divide by the number of revolutions.
  • keef66keef66 Posts: 13,286
    can you not do the rolling tyre test? chalk mark on the tyre and path, get on it and ride slowly counting the revolutions (much easier with a helper) then measure the distance and divide by the number of revolutions.

    I think he already effectively did this via the Blackburn chart. Unfortunately the computer appears to need a different number. My Halfords computer is the same; it seems to require a number that isn't the circumference of the inflated tyre (???) but fortunately I kept the instructions
  • keef66keef66 Posts: 13,286
    http://www.topeak.com/mediafiles/assets/583/file/1

    according to that 23c = 2132
    and 25c = 2146
  • pinnopinno Posts: 38,242
    Thanks Keef 66. Have not perused the web site, I will enter the figures and chase trucks. When the truck gets to 56mph, I will see if my computer is near enough :D

    Yep, did all that rolling/measuring thingy - was way off.
    S - The Brazilian beach volleyball team
    W - Wiggle Honda

    "This year will be harder than last year. But that is good news; this year will be easier than next year." President of Abyssinia's annual address to the nation.
  • All of our manuals are on the Topeak.com site. Start here: http://www.topeak.com/products/Computers then select the model you have and look to the right of that page. There should be a box to the right titled "Downloads"....find the appropriate language and you'll have all the info you need.

    Eddie O
  • pinnopinno Posts: 38,242
    Hello - somebody left the lights on!

    Thanks steady eddie, but keef66 solved the problem for me, though I will check the site out.
    S - The Brazilian beach volleyball team
    W - Wiggle Honda

    "This year will be harder than last year. But that is good news; this year will be easier than next year." President of Abyssinia's annual address to the nation.
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