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Calibrating my speedo (digital)

Discussion in 'Maintenance and Servicing' started by MadAzz300, Jul 30, 2012.

  1. Helloo,

    I think my speedo is out. I followed my partner yesterday, and compared resting at 60km/h - he pulled away from me and reckons I couldn't have been doing more that 54km/h.

    I have checked and cleaned the sensor/magnet which are all good. Then I checked the circumference of my tire (1700mm) and checked the factory setting on the bike (set at 1790mm).

    My tires (according to the manual) should have been factory 90/90 - 16 on the front and 120/80 - 16 on the back, but I have 90/80 - 16 on the front and 120/70 - 16 on the back.

    My questions are

    - do you set the circumference to the exact measurement of your tyre?
    - can the tire pressure affect the circumference? (I can probably google that)
    - would 90mm give me a reading 6(ish) km/h out on the speedo?

    Thanks and apologies if this topic has been flogged to death.

    Cheers, Lee
  2. 1 Not sure on the exact answer one would think yes, or at least round it to the nearest amount.

    2 yes but not likely by more than 5-10mm.

    3 Depending on the accuracy, yes it would easily account for this much.
  3. Thanks, I think I'll use my phones speedo app to record the trip tomorrow morn and see the max speed it picks up. Might give me an indication. Could be the ute's speedo is out.
  4. Just about all speedos read higher than your actual speed. Since 2006 ADR's have required that no speedo can show any positive error. To get around this restriction automotive and motorbike companies deliberately calibrate the speedo to read higher than actual speed.

    An explanation from ADRs says

    "5.3. The speed indicated shall not be less than the true speed of the vehicle. At the test speeds specified in paragraph 5.2.5. above, there shall be the following relationship between the speed displayed (V1 ) and the true speed (V2).
    0 ≤ (V1 - V2) ≤ 0.1 V2 + 4 km/h."

    This formula means that the vehicle's actual (true) speed must not be greater than the displayed speed. (Displayed speed minus true speed must be greater than or equal to 0, and less than or equal to 4kmh plus 10% of true speed). This means that if your vehicle's actual speed is 100kmh, the displayed speed is permitted to be anywhere between 100kmh and 114kmh.

    Prior to 2006 an +/- error of 10% was allowed.
  5. I got my R1 secondhand. The gent that had it before me had changed the amount of teeth on the sprockets. How much was it out? 15.3%. A real pain in the ass.

    I tested it with my awesome bush mechanic skills. Cable ties, a rubber iPhone case (for non slip) and an iPhone 'speedo' app (free). Took a quick spin in every speed zone available. 50, 60, blah blah. Wrote down the results of both and put them into the online calculator at SpeedoHealer.com

    4 days later I had my speedo healer on the bike. Now I can change out the sprockets to what ever I want. Just a quick test and calibration and I'm good to go.

    I highly recommend this product. Highly! A lazy $160 and 15-20 mins of your time. Good luck.
  6. cjvfr does that mean the manufacturer sets the display to read over the actual speed on purpose? I suppose if it read under and I got a speeding ticket, fought it, and proved it was set wrong by them, they could be held accountable? (if my thoughts on this are wrong, blame the time :))

    Thanks Kewish, I'll look into that for sure.

    Ran the app today and theres only 1km difference. Must be the ute.

    Thanks again for all the help :)
  7. or in english when your doing 100km on the speedo you can be doing anywhere between 86 and 100kms
  8. That's awesome SMA. 1km var... you are lucky. I wouldn't worry about the Speedo Healer if that's the case. Unless you put it on the Ute! lol.
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