Speedometer Variation.
Submitted: Tuesday, Aug 11, 2009 at 08:33
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Member - Richard H (NSW)
I purchased a Mitsubishi Triton 4 x 4, a bit over 12 months ago.
On a recent trip the Garmin navigator I have installed displayed the speed about 8 KPH lower than the speedometer displayed when doing about 80kph. This was confirmed with a Garmin GPS 12.
Though this variation is in my favour, so to speak, when I am not pulling a caravan, I'm like a great many motorists and take a chance by exceeding the speed limit a bit. Living where I do, it is just not a viable option to observe the speed limit on the open road as it takes far to long to reach anywhere. NSW & SA haven't woken up to the fact that a 130 Km speed limit is a viable option on some of the highways in the west or north of their respective states.
After all of that, my question is this? Is it normal for speedometers to display an inaccurate reading, and if so, can vehicle warranty fix this up.
If the inaccuracy goes one way, what is to stop it going the other, and display a lower reading than the speed in which one is actually travelling at, to the detriment of ones wallet and driving record.
Reply By: Volvo driver - Tuesday, Aug 11, 2009 at 08:51
Tuesday, Aug 11, 2009 at 08:51
the speedo in my wife's s11 au is out by about 6k's..yet the 80 series is spot on, using a vicroads speed check and handheld GPS,
a 10% error factor is supposed to be acceptable to the govt and the car industry, l believe.. read that in the papers all the time now..
but the error can't isn't supposed to be the other way..show you doing 100 when you're actually doing 120 or so
AnswerID:
378478
Reply By: Member - Mark (Tamworth NSW) - Tuesday, Aug 11, 2009 at 09:06
Tuesday, Aug 11, 2009 at 09:06
Richard
Subject of previous posts. From memory, one authoritive looking reply said it is due to some ADR which states there is nil tolerance for speedos underestimating actual speed but tolerance for overestimating.
Hence vehicle manufacturers err accordingly. My 07 Pajero does something, not my previous 02 one. My 01 Falcon likewise, around 6-7% error.
AnswerID:
378482
Follow Up By: Member - Mark (Tamworth NSW) - Tuesday, Aug 11, 2009 at 09:09
Tuesday, Aug 11, 2009 at 09:09
PS you can verify it if you ever check your odometer against those roadside 5km markers the state road authoroties place on various rural roads.
Your odometer should thurn over 5.0km about 200-300m before you get to the 5km post.
FollowupID:
645861
Reply By: Member - TonBon (NSW) - Tuesday, Aug 11, 2009 at 09:31
Tuesday, Aug 11, 2009 at 09:31
I have found that in the last 4 cars I have owned, all from new, the speedo's have read between 5 and 8 Klm's slow. Yet, I have a 1986 Hilux that reads spot on, according to GPS. I can only assume, and this is only a theory, that it is an in built safety zone to ensure that when driving to the posted speed limit, you are actually going slightly under it to avoid getting fined and sueing the car manufacturer for a high false reading...maybe.
Tony
AnswerID:
378484
Reply By: Member - Fred B (NT) - Tuesday, Aug 11, 2009 at 09:46
Tuesday, Aug 11, 2009 at 09:46
Hi Richard,
changing the rolling diameter of the tyres on your vehicle (eg different than those specified by the vehicle manufacturer) will also affect your speedo. But as others have said, manufactures err on the low side as it is illegal to err the other way.
My Prado, with original tyres is spot on. Mates prado is about 5k the difference, but he also has different tyres. Can't say if its the tyres or speedo.
AnswerID:
378487
Follow Up By: Member - Howard T (QLD) - Wednesday, Aug 12, 2009 at 12:17
Wednesday, Aug 12, 2009 at 12:17
Hi Fred
Its interesting to read your comments. I have a 2009 Prado and the speedo is 5k out to my GPS. (Actual 95 when vehicle speedo reads 100). My vehicle has original tyres.
Cheers
Howard
FollowupID:
646017
Reply By: howesy - Tuesday, Aug 11, 2009 at 10:02
Tuesday, Aug 11, 2009 at 10:02
If your overly concerned you can purchase speedo correctors for around the 100 dollar mark and jaycar also sell a kit that you put together yourself if your that way inclined. I have been using the Jaycar kit in my V8 ute for 4 years after changing diff ratios and had no probs at all its great and if you change to 33's and the back to 31's its just an easy adjustment and your speedos right.
AnswerID:
378489
Follow Up By: Star Bug - Tuesday, Aug 11, 2009 at 20:53
Tuesday, Aug 11, 2009 at 20:53
Fitted a Jaycar kit to the patrol a few months ago. The Speedo had read about 5% under real speed, Then I put bigger tyres which made things worse again. After fitting the kit it reads within +/- 1% compared to a GPS.
Kit was about $54 plus $5 for a case.
FollowupID:
645936
Reply By: Foxhound (WA) - Tuesday, Aug 11, 2009 at 10:45
Tuesday, Aug 11, 2009 at 10:45
Richard, This is ADR 18/03, All new vehicles manufactured after 1 July 2006.
All passenger and light good vehicles including 4x4 vehicles must read 6 km/h faster. Motor cycles 8 km/h faster and Mopeds 4 km/h faster. I believe this is an international rule. Reason I do not know. A lot of people have complained to the dealers on this but that is how they have to read by law.
AnswerID:
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Reply By: WYSIWYG (Bundaberg Qld) - Tuesday, Aug 11, 2009 at 11:04
Tuesday, Aug 11, 2009 at 11:04
Hi Richard,
Have a look at the link below, it has some interesting info and sort of explains the 'error' parrameters.
I haven't followed the laws /regulations for speedo's for quite some time now so things have probably changed somewhat. It used to be that (QLD) a speedo was permiited to be out by 10% before it was deemed to be defective.
This didn't mean you automatically had a defence against a speeding ticket, it just meant that your speedo was not classed as being defective.
As I said things have probably changed a lot over the years but I believe the info in the link is still current.
http://en.wikipedia.org/wiki/Speedometer#Australia
Cheers
AnswerID:
378499
Follow Up By: Nomadic Navara - Tuesday, Aug 11, 2009 at 20:05
Tuesday, Aug 11, 2009 at 20:05
I would not put much credence on what your link suggests, it seems to indicate that spedos can be +/- X%. Speedometers are not permitted to under-read
PeterD
FollowupID:
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Follow Up By: WYSIWYG (Bundaberg Qld) - Tuesday, Aug 11, 2009 at 20:59
Tuesday, Aug 11, 2009 at 20:59
Fair enough Nomadic,
I was reading ADR 18/02 which gives the +/- but 18/03 says equal to or less than actual speed.
Cheers
FollowupID:
645939
Reply By: Members Paul and Melissa (VIC) - Tuesday, Aug 11, 2009 at 16:11
Tuesday, Aug 11, 2009 at 16:11
Yep thats how they are now,my old Hiace(04) was reading 5km/hr faster than i was actually going and my new Hiace(08) is 9km/hr up on my actual speed. seems to get higher as the years get on.
AnswerID:
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Reply By: Nomadic Navara - Tuesday, Aug 11, 2009 at 20:09
Tuesday, Aug 11, 2009 at 20:09
Calibrate your speedometer with your GPS and do not exceed the resultant correction. Just get used too the fact that your speedo is near its limit of the specification.
See this link
AnswerID:
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Reply By: kend88 - Thursday, Aug 13, 2009 at 21:16
Thursday, Aug 13, 2009 at 21:16
Don't fall into the trap of thinking that if your speedo is out 5kmh at 100kmh it will be the same km out at other speeds.
Most likely it will be out less than 3 at 60, but more than 6 at 120.
Ken D
bris
AnswerID:
378905