How Accurate Is Your Speedo ?
Moderator: RichardW
How Accurate Is Your Speedo ?
Hi Folks,
I have often wondered how accurate the speedo was on my car.
But never got round to doing a check using a measured distance (Mororway Juntions) against time say doing an indicated 60mph.
Then the other day I borowed my sons GPS device, and I was able to do a direct comparison.
Both the speedo's on my Bx's were reading 10% fast at 30MPH, and 7% fast at 70 MPH.
I thought that this was a little strange, expecting them to both read high, as I thought the springs in the speedo heads would have relaxed a little due to the miles the cars had travelled.
Any one else carried out simillar tests?...
I have often wondered how accurate the speedo was on my car.
But never got round to doing a check using a measured distance (Mororway Juntions) against time say doing an indicated 60mph.
Then the other day I borowed my sons GPS device, and I was able to do a direct comparison.
Both the speedo's on my Bx's were reading 10% fast at 30MPH, and 7% fast at 70 MPH.
I thought that this was a little strange, expecting them to both read high, as I thought the springs in the speedo heads would have relaxed a little due to the miles the cars had travelled.
Any one else carried out simillar tests?...
Brian - 86 Visa 17D Sorn(192K)/ 86 BX 17RD (220K) Scrapped/ 92 BX 17TZD Turbo Diesel (191K)
96 306 XRDT (174K)
96 306 XRDT (174K)
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- Posts: 1503
- Joined: 26 Feb 2003, 10:52
- Location: Yorkshire
- My Cars: Current:
Volvo V60 D4 180
Previous:
BX16RS (two of),
BX19TZI,
Xantia 2.0i saloon,
Xantia 2.0 Exclusive CT turbo Break,
Peugeot 807 2.0 HDi 110,
Renault Grand Scenic, 2.0 diesel (150bhp)
C5 X7 2.0 HDi 160 which put me off French cars possibly forever - x 16
-
- Posts: 1503
- Joined: 26 Feb 2003, 10:52
- Location: Yorkshire
- My Cars: Current:
Volvo V60 D4 180
Previous:
BX16RS (two of),
BX19TZI,
Xantia 2.0i saloon,
Xantia 2.0 Exclusive CT turbo Break,
Peugeot 807 2.0 HDi 110,
Renault Grand Scenic, 2.0 diesel (150bhp)
C5 X7 2.0 HDi 160 which put me off French cars possibly forever - x 16
- DHallworth
- Donor 2023
- Posts: 2387
- Joined: 20 Nov 2005, 17:05
- Location: Glasgow
- My Cars:
- x 125
Or, you could find a motorway, cruise at 120 kph (slightly illegal) and time yourself over two kilometres based on the posts at the side of the road.
Jamie
Jamie
My other car is a motorbike: Honda VFR**************[VIN obfuscated, can be read by forum staff] 800 Fi
Current car: C5 Petrol 2.0 Exclusive Auto SE
Past cars: Xantia 2.0 Exclusive, Xantia SX, BX 19 GTi (possibly the best car I've ever owned), Visa GT etc etc
Oh, and my son's the proud owner of a Saxo VTR!
Current car: C5 Petrol 2.0 Exclusive Auto SE
Past cars: Xantia 2.0 Exclusive, Xantia SX, BX 19 GTi (possibly the best car I've ever owned), Visa GT etc etc
Oh, and my son's the proud owner of a Saxo VTR!
Aha! That explains why I have had so many speeding fines over the years! I knew it couldn't possibly be due to my driving.. *looks angelic* lol.
James. (Nr M67 East of Manchester).
Dark Blue ZX 1.9D Auto 1994 'L' 5 dr (modified) Aura. 98K miles used daily. Ave mpg 40
Wedgewood Blue 75 CTD auto Connoissaur. 2002. 144k. used daily. ave mpg 40 ish.
Dark Blue ZX 1.9D Auto 1994 'L' 5 dr (modified) Aura. 98K miles used daily. Ave mpg 40
Wedgewood Blue 75 CTD auto Connoissaur. 2002. 144k. used daily. ave mpg 40 ish.
-
- Posts: 1503
- Joined: 26 Feb 2003, 10:52
- Location: Yorkshire
- My Cars: Current:
Volvo V60 D4 180
Previous:
BX16RS (two of),
BX19TZI,
Xantia 2.0i saloon,
Xantia 2.0 Exclusive CT turbo Break,
Peugeot 807 2.0 HDi 110,
Renault Grand Scenic, 2.0 diesel (150bhp)
C5 X7 2.0 HDi 160 which put me off French cars possibly forever - x 16
The posts at the side of British motorways are less accurate than our speedometers.allmond wrote:Or, you could find a motorway, cruise at 120 kph (slightly illegal) and time yourself over two kilometres based on the posts at the side of the road.
As fo rthe accuracy of GPS, at a steady speed it is as accurate as you can get. Shame we can't say the same about speed cameras.