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Thread: Car Speedo Vs GPS
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30th March 2013, 09:31 PM #16.
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- Perth
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Well, I've driven around Perth since 1971 so I should know my way by now but I gave up trying to cope with the roads in the new suburbs so I just punch the coords in and follow the GPS. Sure it's not always right but except for road works, I reckon it gets it right more often than I do - maybe I just get things wrong more often than average. I've used one in the US and Canada where the GPS is hooked into a traffic conditions and road works - now that would be an improvement.
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31st March 2013, 10:23 AM #17
Nope.
I got done years ago in my Torana. One of 3 occasions when I KNOW I was not speeding. I took it to the racq and they tested the speedo. It was within 1 mph at all the relevant speeds. The EL falcon speedo is bang on according to the gps, I've tested it on many occasions on dead straight roads at constant speed to be sure. The subaru is dead on 10% low at all speeds.
Don't even get me started on motorcyclesI'm just a startled bunny in the headlights of life. L.J. Young.
We live in a free country. We have freedom of choice. You can choose to agree with me, or you can choose to be wrong.
Wait! No one told you your government was a sitcom?
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31st March 2013, 03:13 PM #18.
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- Perth
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My old R60 BMW had a very strange speedo. It would not even get off zero until it was doing ~30 mph and then it went straight to 30 mph, then up until about 50 mph it read +/- 5 mph but above that it started swinging back and forth like a yoyo. I replaced the cable but no change, it must have been something inside the meter unit itself. Fortunately that MC was a slow old thing and although I got pulled over a few times I never got fines or points while riding it. The closest I came was in my first out of teachers college, teaching high school in a small country town, when a new young copper, who looked like he was just out of school himself, pulled me over and said I was speeding - I knew I was doing over 50 because the speedo needle was swinging. When he found out I taught maths at the local high school he asked me if I could help him with some year 9 maths homework he was doing at the local tech. Of course I said yes and he then gave me a warning for doing 55 mph in a 45 zone. It was only later I realized this potentially amounted to some form of corruption but he never took me up on the help.
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1st April 2013, 07:38 AM #19GOLD MEMBER
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- Apr 2011
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- McBride BC Canada
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- 2,999
From my house in the village to the house in the city where I stay was 221km.
Every time. So, after 17 years, I replaced it with a less-old vehicle.
Now, the very same route at the very same speed, +/- one vehicle length, is 230km. Every time.
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1st April 2013, 09:47 AM #20
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9th April 2013, 01:30 PM #21I'm just a startled bunny in the headlights of life. L.J. Young.
We live in a free country. We have freedom of choice. You can choose to agree with me, or you can choose to be wrong.
Wait! No one told you your government was a sitcom?
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7th July 2013, 09:14 PM #22
Just to throw a different spin on this - I changed the gearing on my GSX-R and had it dyno tuned and also asked them to make a note of what speed the dyno was reading when the bike showed 100km/h. From that I bought a little gizmo to allow speedo calibration/changes so I did the math and set it up so 100 on the bike should actually be 100.
I go cruising by cars on the highway all the time, I'm sure they're cursing me as another speeding motorcyclist! Haha. But I hold the same speed around police and through cameras, radar traps etc. and have not got a ticket yet.
So the speed on a dyno is accurate, or close enough that you won't get a ticket in QLD if you calibrate your speedo to it!
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8th July 2013, 01:41 AM #23GOLD MEMBER
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- Jun 2005
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- Helensburgh
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- 6,891
ADR's mandate that a speedo must read fast by a certain percentage.
CHRIS
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8th July 2013, 05:16 PM #24
What is any possible reason for having deliberately inaccurate speedos??
Anyway, thems the rules. Didn't know that before.
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8th July 2013, 08:32 PM #25GOLD MEMBER
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The driver cannot claim that because the car was clocked speeding the speedo was in fact slow and indicating compliance with the law. Another way of saying it is if you are doing the indicated speed limit you cannot break the law.
CHRIS
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8th July 2013, 10:38 PM #26Senior Member
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- Feb 2011
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- Gold Country
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- 45
GPS ha! I work for a Large transport company which has GPS locators in the vehicles and guess what? The GPS program installed that I use to see where drivers are to allocate jobs cannot get the speed zone right. Often says a speed zone is 100km/h and its in the middle of the city in streets that are 50km/h zones. Trucks can be parked in the yard and the system will say they are doing 30km/h.
I'd like to hear of anyone getting off a speeding ticket due to "but officer the GPS said....."
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8th July 2013, 10:52 PM #27GOLD MEMBER
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- Jun 2005
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- Helensburgh
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My daughter works for Ezi Track who supply onboard GPS tracking back to base or to your phone. A few years ago a motorist who had one of their trackers fitted was pulled over and booked for exceeding the speed limit. 18 months later (I might be wrong here on the time frame) the driver finally had the infringement overturned after a lengthy court battle after the police were proven wrong by the tracker logs. The GPS trackers in our trucks have a button on them top mark a point in the log if you want to question speed etc at the marked point.
CHRIS
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14th August 2014, 12:07 AM #28Still Learning
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- Aug 2014
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- Perth, Western Australia
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- 72
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I don't think the ADR's have changed for speedos: +-10%. Road Safety WA: 'Drop 5, Stay Alive'. Daughter: 'Add 10, Live on the Edge'. Where did I go wrong?
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14th August 2014, 01:30 AM #29
From ADR 18/03 http://rvcs-prodweb.dot.gov.au/files/ADR%201803.pdf
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
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14th August 2014, 08:21 AM #30Still Learning
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- Aug 2014
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- Perth, Western Australia
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- 72
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I stand corected.
But this will be for cars after the ADR was declared. Older vehicles (like mine) will still be on the + -10% .