Incorrect speedo reading on new vehicle
Submitted: Monday, Nov 23, 2009 at 18:25
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73948
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16
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briggzee (WA)
Hi all, have recently purchased a new Colorado and am generally very impressed with it but have one small problem. The speedo reading shows 5-8kms faster than what the car is actually doing (according to the GPS). Have spoken to the holden dealer who said "it's built that way as a safety mechanism and can legally be 10% out". That sounds like a load of BS to me and is just a copout. Is this correct? Has anybody else encounterted this on a new vehicle?
Any feedback or advice gratefully accepted, thanks in advance.
Craig.
Reply By: DIO - Monday, Nov 23, 2009 at 18:35
Monday, Nov 23, 2009 at 18:35
What they say is in fact in accordance with Holden's specifications. I have had numerous 'discussions' with several Holden Service 'Advisors' and I might as
well spend my time trying to discuss the weather with a frog. Some vehicles, in particular any ordered for Police service do in fact have more (almost perfect) accurate speedos. The arguement in favour is that it stops people from exceeding the speed limit if the speedo reads high. In your case say 65 - 68 km/ph is near enought to 60 km/ph - that's if your GPS is providing an accurate reading. One of my vehicles - a 2007 Commodore is 3 km/ph fast across the range.
AnswerID:
392343
Follow Up By: Member - Wyknot (Qld) - Monday, Nov 23, 2009 at 22:12
Monday, Nov 23, 2009 at 22:12
wrong, Qld police vehicles are also delivered reading slow and have to go on the dyno machine and have the speedo's corrected. The only difference between a Police vehicle and the average vehicle is that police vehicles have their speedo's calibrated in 2kph increments and not 5kph increments
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Follow Up By: Member - mazcan - Tuesday, Nov 24, 2009 at 11:29
Tuesday, Nov 24, 2009 at 11:29
hi
its a very common problem tested using 3 different gps units
an l series 4wd subaru 4kph slow
a nissan pulsar spot on
a mazda bravo 3kph slow
a vw golf 6kph slow
and an au falcon 4kph slow
i drive by my gps unit speed and have passed through many speed checks thruogh-out w.a and never been booked so i'm confident that the gps speed is accurate
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660363
Reply By: Sand Man (SA) - Monday, Nov 23, 2009 at 18:39
Monday, Nov 23, 2009 at 18:39
Hi Craig,
May I suggest you check it with another GPS just as a double check.
My Colorado registers 2 kilometres per hour slower than both my Tomtom Navigator and my PDA running Oziexplorer readings, so I reckon that is pretty accurate.
This just happens to be the same as my previous Jackaroo SE Auto.
I assume you have standard
wheels 245/70/16's ???
Bill.
AnswerID:
392344
Follow Up By: briggzee (WA) - Monday, Nov 23, 2009 at 19:06
Monday, Nov 23, 2009 at 19:06
Bill, I did think that the gps might be wrong but I didn't think that would be possible. Can GPS's give incorrect readings? I have garmin nuvi.
thanks Craig
FollowupID:
660286
Follow Up By: Richard Kovac - Monday, Nov 23, 2009 at 19:11
Monday, Nov 23, 2009 at 19:11
briggzee
just go for a drive up Roe Hwy, sit smack on 100 km/hr and if everyone passes you the speedo must be wrong :-)
Cheers
Richard
FollowupID:
660287
Follow Up By: briggzee (WA) - Monday, Nov 23, 2009 at 19:36
Monday, Nov 23, 2009 at 19:36
Richard, I know what you mean. The new
Forrest hwy is even worse. (but magnificant to drive on).
Cheers, Craig
FollowupID:
660291
Follow Up By: Richard Kovac - Monday, Nov 23, 2009 at 19:42
Monday, Nov 23, 2009 at 19:42
Craig
I've got a 2WD Hilux Ute thats is the slowest car on the Roe, but also 5 k's slow on the PDA and GPS. that may explain why I haven't had a speeding fine in 20 years and why so many people stick there finger up at me.. LOL
Cheers
Richard
FollowupID:
660292
Reply By: Member - Cozzie Toodyay (WA) - Monday, Nov 23, 2009 at 19:36
Monday, Nov 23, 2009 at 19:36
My Colorado is the same about 6kph out and got the same load of crap from my Holden dealer.
AnswerID:
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Follow Up By: dbish - Monday, Nov 23, 2009 at 19:43
Monday, Nov 23, 2009 at 19:43
As an X Ford mechanic speedos in Ausie made vehicles are made atleast 5Khr fast Ford & Holden instrument panels were made by Bosch Aust, police vehicles had a different speedo & calibration in the instrument panel. I would say the GPS would be the most accurate.
FollowupID:
660293
Reply By: Madfisher - Monday, Nov 23, 2009 at 19:37
Monday, Nov 23, 2009 at 19:37
Previous toyota 4runner of
mine was doing 94 at an indicated 100, and a
Tarago at work showed similar fig. It better to read fast then slow. If travelling in convoy we tend to use a falcon as the lead vehicle as they are accurate with in a couple of ks.
Cheers Pete
AnswerID:
392349
Reply By: get outmore - Monday, Nov 23, 2009 at 19:39
Monday, Nov 23, 2009 at 19:39
way back when definitly before GPS the
wheels tests used to show actual vs speedo readings
- so speedos have been reading fast since then at least.
older holdens were notorious for reading up to and over 20kph fast.
Had a mate in a hx 202 ute who used to sit on about 150kph nearly everywhere.
one day i doddled along behind him at a lesuraly 125-13k0kph in my valiant
when we pulled up he asked how i was going keeping up
- thats how he found out
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Reply By: Isuzumu - Monday, Nov 23, 2009 at 19:47
Monday, Nov 23, 2009 at 19:47
All car manufacturer's do this so we do not get caught speeding. Have you every noticed when your doing 103 kph and the radar cop goes past he does not do the big u y and come chasing you. Every vehicle I have driven with a GPS in it has been the same, as long as they are running the standard tyres.
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Reply By: howesy - Monday, Nov 23, 2009 at 20:09
Monday, Nov 23, 2009 at 20:09
If your that worried about it nippon down to jaycar and purchase a speedo corrector. Got one in my car and set it so It shows 1Km over at 100km/h (actual speed 99)
They work great and if you change diffs or tyre sizes you can re-correct.
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Reply By: Member - Kroozer (WA) - Monday, Nov 23, 2009 at 20:12
Monday, Nov 23, 2009 at 20:12
My 2004 Prado is the same, sitting on 115km/h the GPS reads 112km/h, its accurate up until about 95km/hr. Sitting on 120km/h GPS reads 115km/h.
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Reply By: Member - Kevin B1 (WA) - Monday, Nov 23, 2009 at 20:39
Monday, Nov 23, 2009 at 20:39
This topic has been discussed before and it is an Australian design rule that came into force on 1 July 2006. Australian Design Rule 18/03 Instrumentation states in brief, that any new model vehicle manufactured after that date the speedo should read. Passenger vehicles up to and including trucks must read 6km/h faster Motor cycles 8 km/h faster and Mopeds 4 km/h faster. It appears to be an international rule as it states in the definitions that it was adopted by the
United Nations. Why they decided to go down this path who knows, just another rule to contend with.
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Follow Up By: Member - Teege (NSW) - Tuesday, Nov 24, 2009 at 08:34
Tuesday, Nov 24, 2009 at 08:34
Kevin
I have to disagree with you. I've just re-read that ADR and it 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"
Para 5.2.5 says, among other things, if the maximum speed of the vehicle is in excess off 150kph the test should be conducted at speeds of 40, 80 & 120 kph. The little bit of gobbledegook at the end (V1,V2 stuff) simply determines the amount of error allowed, but this must always indicate a speed not less than the true speed. The way I read it is that any speedo can have up to that margin of error, but it does require them to have one.
teege
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Follow Up By: Nigel Migraine - Tuesday, Nov 24, 2009 at 14:49
Tuesday, Nov 24, 2009 at 14:49
Teege is correct.
Before you use GPS to measure vehicle speed you need to understand the Nyquist theorem. GPS speed is only correct in a straight and level line.
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Follow Up By: Member - Kevin B1 (WA) - Tuesday, Nov 24, 2009 at 15:25
Tuesday, Nov 24, 2009 at 15:25
Teege,,,You are correct there is no actual requirement to have exactly that error but in my experience most new vehicles do show around + 6 km/h faster. Since 2006 I have owned two new vehicles a Nissan and now a 2008 Land cruiser and both read exactly 6 kp/h fast in all conditions, that is assuming the GPS is correct. Reading the forums most people with new vehicles seem to be getting the same results.
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Follow Up By: Member - Mike DID - Tuesday, Nov 24, 2009 at 18:05
Tuesday, Nov 24, 2009 at 18:05
Before GPS became so popular, people just didn't know how inaccurate their speedo was !
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660411
Follow Up By: Member - Mike DID - Tuesday, Nov 24, 2009 at 18:07
Tuesday, Nov 24, 2009 at 18:07
"Before you use GPS to measure vehicle speed you need to understand the Nyquist theorem"
And how does Nyquist's Theorem come into it ?
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Reply By: Member - Stephen L (Clare SA) - Monday, Nov 23, 2009 at 21:04
Monday, Nov 23, 2009 at 21:04
Craig
Like many above, it is better to have it that way than the other. Our last Pajero when doing 100kph by the speedo, GPS would read 95 and I knew that I had a little up my sleeve. The Problem now with our Prado is far less. When the speedo is showing 100kph, the GPS is now only 1 kph slower, showing 99kph.
In this situation, there is far more chance of going slightly over the posted speed if not careful.
Cheers
Stephen
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Reply By: Crackles - Monday, Nov 23, 2009 at 21:26
Monday, Nov 23, 2009 at 21:26
I find the inbuilt error perfect as I always fit oversized tyres & then the speedo is only 1kph out :-)
Cheers Craig...........
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Follow Up By: StormyKnight - Tuesday, Nov 24, 2009 at 21:07
Tuesday, Nov 24, 2009 at 21:07
Ditto!
Just go up a size in tyre gets you about 3% adjustment LOL
90 series now reading 1% slow with 265/75R16's
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Reply By: AlbyNSW - Monday, Nov 23, 2009 at 21:31
Monday, Nov 23, 2009 at 21:31
The current model hiluxes all do the same, I have fitted bigger rubber and
mine now reads spot on. Apparently as long as they are within 10% they are within spec and not considered faulty
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Reply By: TerraFirma - Monday, Nov 23, 2009 at 21:53
Monday, Nov 23, 2009 at 21:53
My Hilux does the same reading 5KMs faster and yes some GPS systems read different speeds. I do not have a problem with 5KM's over I think it is a good thing with speed cameras booking you for 4-5 Km's over etc. When on longer trips I put the cruise control on and set the speed acccording to my GPS, that way there is no stress.
The simple things in life are often the ones that bleep you off.!
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Reply By: Serendipity (WA) - Tuesday, Nov 24, 2009 at 00:27
Tuesday, Nov 24, 2009 at 00:27
Hi Briggzee
I have one of those V8 landcruiser utes and my speedo is out like yours. I purchased a ScanGauge and zeroed that using my GPS so I know exactly what speed I am doing.
David
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Reply By: briggzee (WA) - Tuesday, Nov 24, 2009 at 12:08
Tuesday, Nov 24, 2009 at 12:08
Thanks for all the replys. It looks as though I have to get used to it or purchase a scangauge or fit bigger tyres!
Thanks
Craig
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Reply By: Member -Dodger - Tuesday, Nov 24, 2009 at 15:23
Tuesday, Nov 24, 2009 at 15:23
I have three different types of GPS units and they all read the same speed when travelling.
As I have slightly larger tyres on the Patrol it means that when the vehicle speedo reads 100kph the vehicle is actually travelling at 103kph.
But figure this the odometer/distance after travelling 100klm on a flat straight road is 5klm less than what all the gps machines read. not 3klm as I would expect.
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