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Over Reading Speedo

Discussion in 'Technical and Troubleshooting Torque' started by doonx, Feb 24, 2005.

  1. I was trolling up Wellington Rd the other day passing other traffic but by no means wizzing by, probably no more than 5-10kph quicker. I looked at the speedo and it was pretty much saying I was doing 100k's. I looked around at the roadside, fences, etc and thought that there was no way I could be doing 100k's. I know I can motor along beside Tam in the car and do a speedo comparison at 80k, 90 and 100kph to find out if I'm over reading.

    If I am, is there a cure ?

  2. slow down? *G*

    i think there are places that can fix it but i dont know where
  3. Most speedo's over-read, better to over-read than under-read ;)
  4. there are many things depends on the speedo, yellow box is a good one but i believe you need digital not cable speedo really not sure thought.
    Go for a ride with a GPS and compare or even a few others on the forum have fitted those pushbike digital speedos to there bike
  5. Huh... I think maybe my ZZR speedo is over reading too... I was tailing my man in our mini and commented later that he was going 120 in a 110 zone the whole trip. Apparently, my gauge showed 10kph faster than his did, as he was sure he was going only 110, due to the large number of piggies on the road. We've checked it since and had about the same level of difference.

    Is this a common thing for bikes? I know that speedo inaccuracy is common at much higher speeds, but at 110?!? And is there any thing they can do about this at my next service?
  6. it is common for a Kwaka speedo to read 10% faster, seems to be a tweak they have stuck with
  7. Comparison to other vehicles is always subjective. Better to find one of those sites (like the Wetern Highway ) where they have speed checks displayed to oncoming drivers.

    Almost all bikes are a optimistic on speed readings.
  8. yes, i agree, better to over read than to under read <insert police siren wahhhh wahhh noise>
  9. I'd test it at a road speed check. There's 1 on the Westwern Hwy, the Princess@ Geelong (northbound) and Northbound on the Hume between Craigiburn and Kalkallo. Once you know what the difference is you can simply account for it. It is possible to have a speedo recalibrated but it's a bit of a waste of money really.
  10. to date i've never been seen by those speed checks on the bike and the one near Ballarat barely works anyway.
    Also dont rely on the speed check signs to be accurate there also required to be out after the court case around 2 years or so ago.
  11. have u changed to different sprockets???
  12. I think that if speedos are going to be "out", then they will often over read than under read. Not always true but it seems to be more common for this to occur - which is better of course.

    Although some think those speed checks are not accurate, I haven't noticed them to be. I've used a GPS unit in my car and basically the GPS unit showed the same speed as the on that displayed on the speed check. Some places you service a bike at should be able to recalibrate the speedo but it is quite costly considering the task...just remember how far out the speedo is (the error is often exacerbated the faster you go) and adjust your speed accordingly.

    I believe my bike speedo is fairly accurate but in my cage I know that:
    62 on the speedo is really = 60
    83 on the speedo is really = 80
    104 on the speedo is really = 100
    117 on the speedo is really = 110

    Not too difficult to remember. Serious! :D
  13. Personally I want mine to be dead accurate with a new set of tyres (as tyre wears it will tend to over read anyway)....

    Can't understand why manufacturers deliberately er on the over read side....

  14. you were probably speeding.. car drivers randomly go stupidly fast or slow for no reason :p

    but yeh, 100km/h feels pretty damn slow once you get used to it (200km/h would too) :D
  15. Friend & I checked our speed coming home from Geelong, both driving Foresters with cruise control on both running dead level front door pillars accurately aligned. both speedo's reading spot on 100k. My lane read 100k's his read 104k's! man he couldn't get on the batphone quick enough to me to object at the inaccuracy!
  16. Yeah, I reckon the ZZR250's must have a tendency to read a little high, when I'm out cruising with Monty, she on the ZZR and me on the CB250 she always says her speedo is reading higher than mine, perhaps about 5 km/h on the highway.
  17. My Spada reads about 8% low.

    Its a miracle I still have my licence :shock:
  18. yeah dont trust those friggin speed check things on the highway from geelong they suck.

    i have been through in the cage and the bike and i get differing speeds all the time on the bike (when it picks me up) and the cage is up and down
  19. as i said on the other page raffiki a few years back someone got done bigtime for speeding not long after going through those speed checks. His defence was the accuracy of the speed check signs he won his case.
    As a result they placed the advisory signs near each speed check and also run them +or- kph, use them as a guide only nothing more.

    The best way to check your speed go hire or borrow a mates hand held gps for the day :)