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Discussion Starter · #1 ·
Hi all,

Just been down a 40mph road that had a police speed camera van on it.

Looked down at my display as soon as I saw the van, and it said 42.

Question is, how accurate is the speedo on 8G Civics? I'm hoping they over read a bit?

Cheers.
 

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you will be fine, pun not intended. over reads by 3 or 4 mph at that speed and the police will only fine if at least 42 real world (GPS) so you would have had to have had 46 showing on your speedo for you to worry.
round my end its 10% plus 2 so 46 real world which is 50 plus on speedo
 

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FN3 Crystal Black Pearl Celtic Stage 1
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Will also depend if you've kept stock wheel size
Mine over reads by 1-2 mph & seems more accurate at higher speeds but most say theirs get's less so. Above 50 mph my speedo seems to keep track with Maps.
Think you'd be unlucky to get done for a genuine 42
 

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Discussion Starter · #6 ·
Hampshire I think is 10% + 1, so in theory you could get away with 45 (again, I think but not 100%)
 

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You'll be fine.

If in any doubt put your phone and maps on the dash, the GPS speed is more accurate...

For my 1.8 with 16" rims a displayed 43mph is 40mph on GPS and 55mph is 50mph. The difference gets wider the faster you go.
 

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MY13 9G Civic Auto
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The pre-facelift Civic was some way out but they improved it on the facelift.

From memory, my 2007 Civic was about 6 mph over read at 70 but my 2009 facelift was only 3 mph over, as is my 9G.
 

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My pre face-lift reads 9% under. So 76 on the speedo is 70 by gps. 43 is really 40. I seem to remember reading the post face-lift this was refined to 4% difference but I can't remember the source of that.

Sent from my SM-G960F using Tapatalk
 

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Discussion Starter · #10 ·
Just down an experiment on way to work using Google maps.

In the 30s, it was reading 2mph over, and in the 40s it was 2 to 3mph over.

So in theory, in a 40 zone in Hampshire, my Speedo could reach as high as 47 or 48, and I may just be on the threshold to not get done :unsure:
 

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2008 Civic Type R
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My pre face-lift reads 9% under. So 76 on the speedo is 70 by gps. 43 is really 40. I seem to remember reading the post face-lift this was refined to 4% difference but I can't remember the source of that.

Sent from my SM-G960F using Tapatalk
Depends on the wheel/tyre configuration and amount of tyre wear (since that is what is being allowed for). A 2008 Type R overreads by about 8% with 18" wheels and 225/40 Goodyear F1 Assy 3's on. Trouble is having to account for the variation in tyre sizes. As an example the Nangkang NS-2Rs are a little larger than most 225/40 summer tyres and so the overread is only 5-6% when new. Accounting for 6 mm tread wear for a worn tyre (12 mm on diameter) they will be overread by an additional 2%.
 
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Hi all,

Just been down a 40mph road that had a police speed camera van on it.

Looked down at my display as soon as I saw the van, and it said 42.

Question is, how accurate is the speedo on 8G Civics? I'm hoping they over read a bit?

Cheers.
They give you 10% for speedometer inaccuracy
 

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MY13 9G Civic Auto
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That 10% + 2 mph is only a discretionary figure. Most speedos now over read so if you're clocked doing say 71mph then your speedo will likely be reading 75mph to 77mph+ so you have no excuse.
 

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MY13 9G Civic Auto
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There are a few exceptions. Have a look at the road barristers:



I've got a colleague who got fined for doing 33mph in Slough. Exactly as mentioned in the link above.

Not a rule but a guideline, as I said.

Speed at your own risk.
 
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