Member Since: 28 Mar 2011
Location: england
Posts: 3
Speedo on a 2008 discovery 3
Hi, i am looking for some help regarding the acuaracy of the speedo on a 2008 automatic LD3 , reason being i was using my bosses car to do him a favour and on the way home i passed a mobile speed unit , iwas doing 34/5 mph ,now on my car the speedo over reads by 10% and in normal circumstances i would be OK under the ACPO guidelines 10% plus 2 , i know its a guideline and i do try to stay at 30mph , i know that a lot of cars speedos overread but with the discoverey being a newish car i am worried i may be over 30mph if the discoveries speedo is accurate, if i did get caught i am just worried as my boss will get the letter....i may be worrying about nothing but i just thought i would ask about the speedos accuarcy. Any help would be apreciated.Thanks
28th Mar 2011 6:04 pm
Gareth Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26702
Unfortunately for you, my speedo is pretty much spot on when compared with a gps.
28th Mar 2011 6:06 pm
den9112
Member Since: 28 Mar 2011
Location: england
Posts: 3
Thanks for the quick reply, i was told that car manufacturers had to have speedos over read between 5% and 10% just clutching at straws ,the speed partnership do speed awereness courses and i have found out the only caution above 35mph so i could be lucky and i am 100% certain i did not go over 35mph on my entire journey as i had a passenger..
28th Mar 2011 6:12 pm
wvlenthe
Member Since: 07 Jan 2009
Location: Arnhem
Posts: 1967
if you compare it to the data that is displayed under the secret button, you will find there is a difference between the speedo and the vehicle signals screen of about 3 km/h (2 mph?), the speedo reads higher.
Having said that, both could be influenced by tyre wear.
regards,
WiljoD3 V8 HSE Auto in Zermatt silver - driveway version gone but not forgotten, only the living room cupboard version remains
28th Mar 2011 6:19 pm
DaveS
Member Since: 15 Aug 2009
Location: Weybridge
Posts: 241
I think that the manufacturers (and drivers) have to have a speedomemter that is accureate to +/-10%. In the past, manufacturers tended to make the read too high to keep their customers happy.
Like Gareth, my speedometer reads almost the same as my GPS, possibly 1mph higher but certainly not 10%.
28th Mar 2011 6:21 pm
Mad Phil
Member Since: 13 Mar 2011
Location: Leicester
Posts: 254
My D3 was 2mph out at 30 & 4/5mph out at 70.
My D4 is 3mph out at 30 & 6mph out at 70.
Compared with Road Pilot Micro & Micro Go (from my other car) at the same time
Hope that helps
Phil
28th Mar 2011 6:23 pm
den9112
Member Since: 28 Mar 2011
Location: england
Posts: 3
Got to say you have a good forum,very impressed with the quick replies. Thanks all.
Last edited by A1GSS on 28th Mar 2011 6:40 pm. Edited 2 times in total
28th Mar 2011 6:35 pm
DG Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
Under EU type approval, the speedometer is permitted to have a maximum variance of 110% plus 2.85 mph above the true speed of the vehicle. Legally the speedo can never show a figure any less than the true speed.21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
28th Mar 2011 6:36 pm
TwelveSticks
Member Since: 16 Jan 2010
Location: Dublin
Posts: 798
Mine's the most accurate I've had too, but still over-estimates by about 4% compared with GPS speeds.
I'm told that with the MSV-2 I can recalibrate it myself, but I have yet to try that out...2001 D2 GS (I must be mad!)
2005 D3 S 10-12 (gone and missed)
28th Mar 2011 7:14 pm
discoBizz
Member Since: 20 Sep 2008
Location: Manchester
Posts: 1416
Member Since: 09 Mar 2009
Location: Littleborough
Posts: 2109
Mine's pretty much the same as the others here, very close to spot-on compared to GPS.
Danger is I suppose if you get used to a speedo being say 5 mph over at 30, you know you can safely drive about at an indicated 35 - 40 and know you're generally safe - then you get in a D3
Maybe that's why you get so many people doing 45 in the 50 limit on M'way roadworks, it's those that just go by the numbers on the clock.Clive
29th Mar 2011 4:26 pm
discoBizz
Member Since: 20 Sep 2008
Location: Manchester
Posts: 1416
...which you can overcome by driving with a Tab stuck to the dashboard
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Thanks DG
