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Speed check devices?

Discussion in 'General Motorcycling Discussion' started by jbray, Dec 23, 2005.

  1. Is there still a speed check device (radar thing with big display on the road above traffic) between Geelong and Melbourne? I haven't been that way for a long time, probably since it was all re-done.

    Are there any others around Melbourne that anyone knows of?
    I've changed the front sprocket and would like to see how much it's out now.
  2. I know there's one between Melbourne and Ballarat but the damn thing hardly ever registers that my bike's there.
  3. The one near Geelong has been turned off (last few times I went past) since they introduced 'safety' cameras along there *cough* *muttering*.
  4. it was working tuesday when i went past.
  5. Which way did you go? Smaller or larger sprocket? Smaller will make the speedo read faster, larger, slower. If you can, get a lend of a GPS and check it that way. It's the most accurate way of doing it, and it'll be as accurate as any cop's radar.
  6. Not quite. A civilian GPS is reasonably accurate, but it does not show 'instant' speed. It shows an average measurment over a period of around 30 seconds, time delayed by up to a further 10 seconds. In other words, what you are looking at is roughly the average of the last 40 seconds. To check a speedo using a gps you would need to maintain a perfectly constant speed for at least 60 seconds, and preferably longer. Trust me, I'm a pilot.
  7. Geelong is back on

    The acuracy of GPS is VERY accurate... It is more accurate than most vehicles.....
  8. It wasn't working when I rode under it on the way back from Geelong on Tuesday. Looks like it has been removed.

    Sounds like they don't want to let people know how fast they are really going - so they can take their photo's further up the road. :p
  9. Hang on.... I live in Geelong, nobody told me... :eek: :LOL:

    Seriously though, I drove up Wednesday and it was there and it was working.... :D
  10. I downgeared the Hornet - a tooth down on the front, one up on the rear - and got something like an 8% discrepancy. There's gearing calculators out there...

    If you're really worried about it, maybe fit a cateye bike computer to be your alternate speedo... But I've pretty much just got used to my new speedo and go around with it indicating 5-10k over the limit.

    The other annoying thing is that it messes with your fuel consumption calculations and also your odometer - I reckon there's a thousand or more k on my odo now just from the downgearing discrepancy.

  11. I said it was reasonably innacurate, I said it was time delayed. Having said that, civilian GPS is intentionally degraded by the US military (who control the satellites), as it would otherwise be very easy to use it for missile guidance. This is no secret, it has been published by the Pentagon for many years.
  12. Have heard the rumour though that a lot of the US military are actually equipped with civilian GPS units (since it's easier to buy them than requisition military units) so during military action the accuracy of civilian GPS is bumped up.
  13. :LOL:

    It's under the Avalon Airport overpass Melbourne bound, there's also one both ways on the Western Freeway near Ballan and near Ballarat.

    There's also one outbound near Beveridge on the Hume but it hasn't worked in years.

    Be aware that after several complaints the signs on the approach to them had the words "Advisory" added due to people with cruise control claiming the speed checkers said they were doing 100 but a copper down the road doing them for a higher speed.
  14. It could be true, the standard US military GPS is a 'ruggedised' Magellan unit based on the 315 civilian model. The degradation is not vast anyway in position terms, around 1-3 meters, it is the response lag that makes it difficult to use for missile guidance. A side effect of this is that GPS is not available as a primary approach aid for civilian aircraft, which still rely largely on VOR and ADF technology developed in the 1940's.
  15. Hey PVDA.

    Interesting, then can we not argue that the radar gun is not accurate either.......????? Hmmm, I think you could definately fight this one in court.... May not win though
  16. the beveridge one still works, it shows my speedo to read about 5km high at 100kmh
  17. I seem to recall reading somewhere that ADR's only require a speedo accuracy of 10% to allow for tyre wear. I believe somebody has already tried to use this as a defence for speeding at less than 10% over the posted limit, and failed.
  18. Yep gotta love the Victorian Government, speedo on a new vehicle only has to be accurate to within 10% but they can book you for being 4kph over the limit :evil: .
  19. yes adr allow 10.

    vic police allow none on speed cameras used to allow at least 3%.

    and they say they are not revenue raising!!!
  20. The GPS I use registers changes in speed within a second or two. Selective downgrading of GPS was improved a lot a couple of years ago. I've had one in a car that was consistently within 10km/h of my speed, and in city traffic.
    I always grab the GPS when I get a new vehicle and check the speedo.
    I thought most bikes took the speed off the front wheel anyway? When did they go to rear wheel sensing?

    Regards, Andrew.