77MPH Speeding ticket M74

77MPH Speeding ticket M74

Author
Discussion

ModernAndy

2,094 posts

134 months

Monday 28th July 2014
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S2red said:
Borrow/get a sat nav great way to check speedo accuracy
One does wonder how accurate the sat nav speed reading is though

S2red

Original Poster:

2,507 posts

190 months

Monday 28th July 2014
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Supposed to be accurate

FRA53R

1,077 posts

167 months

Monday 28th July 2014
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Bloody hell, I've been a lucky bugger these past few weeks, going up to Inverness and clocking speed vans a little late (Other road users obscuring view) when doing around 77-79.

paulqv

3,124 posts

194 months

Monday 28th July 2014
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If you can spot the white marker posts at the side of the motorway, with the blue band and red square.
count the first as 0 and last as 16 that is one mile.
set your cruise control at an indicated 60, don't change lane and see what your time is and make adjustments
To check tyre variation use one of the many calculators on line and work out the speedo variation. ALL speedos by law NOW I think from 1994 (?) must only over read not under by a max of 10%
Also tyre wear makes a difference depending on the way the speedo is working. If minimum tread is say 2mm and max 7.5mm then a 10mm variation from max to minimum in rotation, plus there is inflation and temp, so usually if off a wheel is about +/- 2% variation. you can calculate this all manually but really need tyre manuf figures for tyres to get it spot on
Usually sat nave work well problem being you re dependant on the same sats if using different devices in car at same time
There are marked police 1/2 mile measured areas. In Hamilton on the racecourse road being the yellow posts.

Allandwf

1,754 posts

194 months

Monday 28th July 2014
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I have four cars at present, all speedo's overread between around 3 to 8%. On a side note, does anyone know the accuracy of those signs that show your speed as you approach them?

Ibiza125

82 posts

197 months

Monday 28th July 2014
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S2red said:
No Your speedometer could both underread or overread by 10% so you could be sitting with 70mph on Speedo and be doing anything between 63 & 77mph
Rubbish. You show me a standard car with standard wheels that under reads I will eat my left nut.

I've never seen a car over reading by more than 5mph.

S2red

Original Poster:

2,507 posts

190 months

Tuesday 29th July 2014
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Did not say they did just saying there's a tolerance allowed. Manufacturers make sure they overread so they cannot be blamed if you are caught speeding

Spitfire2

1,912 posts

185 months

Tuesday 29th July 2014
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Ibiza125 said:
S2red said:
No Your speedometer could both underread or overread by 10% so you could be sitting with 70mph on Speedo and be doing anything between 63 & 77mph
Rubbish. You show me a standard car with standard wheels that under reads I will eat my left nut.

I've never seen a car over reading by more than 5mph.
It's rubbish for modern cars. Older stuff was permitted to be 10% out wither way.

Marti99

164 posts

152 months

Tuesday 29th July 2014
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No where has it said what the speed limit was. Could easily have been a 50mph roadwork area. It would also explain why it was taken to court rather than fixed penalty.