2007-02-11 12:20:12 · 13 answers · asked by Anonymous in Cars & Transportation ➔ Other - Cars & Transportation
I would say the car one is wrong
2007-02-11 12:25:01 · answer #1 · answered by Boscombe 4 · 1⤊ 0⤋
I dont have either one of those but assuming they are sattelite based, I might have to go with those- a guess on my part. Here's what I do know; if you changed your tires or wheels from what they were at the factory- meaning that overall you have a bigger or smaller circumfrence, your speedo will be off. I've seen a two to 4 mph difference on my cars from going from 15" to 16" wheels and tires Basically my speedo would read 70 but I was actually going at 74..
2007-02-11 12:46:18 · answer #2 · answered by cy from ma. 1 · 0⤊ 0⤋
The tom tom is more acurate as one of the readers below said tom tom relys on a sattelite for a car in order for your speedometer to be correct all the tire pressures have to be the same the speedometer cable should not be old or frayed and the car must be in great shape.
2007-02-11 13:38:20 · answer #3 · answered by AJ 1 · 0⤊ 0⤋
the Sat-Nav will be more accurate most of the time, but it only updates every 10 seconds or so, so if you are speeding up or slowing down it will lag behind your true speed. Also the Sat-Nav assumes a level road, so will read low on hills. Car speedometers have to read within +10%, so 76 indicated mph at 70 true is within spec, just.
2007-02-11 19:51:55 · answer #4 · answered by The original Peter G 7 · 1⤊ 0⤋
On a level road the satellite-based systems will be more accurate.
On a gradient, they will not be able to allow for the vertical component of your velocity, and so will display a speed lower than your actual surface speed (under-read).
Car speedometers are by law not allowed to under-read.
For this reason they are purposely designed to over-read slightly.
As the car's speedo works by measuring the speed of rotation of the transmission, and not the actual speed of the road surface relative to the car, it will over-read more as your tyres wear, or if your tyres are under-inflated.
However, do not rely on the satellite systems as proof you are within the speed limit - the law allows them to under-read slightly, and as stated before they will under-read on a gradient.
2007-02-11 22:41:06 · answer #5 · answered by Neil 7 · 0⤊ 0⤋
I similar problem. It's significant in terms of speed limits. Short of paying to get your speedo tested better to stick to a reading in between. There is - or was - a 10 per cent error allowed on speedometers anyway
2007-02-11 13:31:48 · answer #6 · answered by lonzo 1 · 0⤊ 0⤋
The sat navs would be more accurate than the speedo.
I'm not saying that they are spot-on exact but they would be more accurate than the speedo.
2007-02-11 12:51:22 · answer #7 · answered by Rob K 6 · 0⤊ 0⤋
the GPS is much more accurate as it uses satellite triangulation to tell you exactly how fast you are going. as a standard, a car speedometers margin of error gets larger as the speed increases. as a result it may read as much as 10mph off when the vehicle is going about 100mph
2007-02-11 12:35:03 · answer #8 · answered by Ksyrium 3 · 0⤊ 0⤋
it depends how old the car is?
most new cars from 2000 have now got electric speedos not cable so i would say they are preety accurate!
2007-02-11 17:33:30 · answer #9 · answered by witheringtonkeith 5 · 0⤊ 0⤋
Your GPS system. Speedo's are built to read high
2007-02-14 09:48:17 · answer #10 · answered by Professor 7 · 0⤊ 0⤋