172 speedo under reading!

[CocoPops]

I fitted my origin b2 over the weekend and discovered that my speedo over reads.

When the speedo says 80, the origin says 75.
It seems to be roughly 5mph above the actual speed?

I am running on the standard wheels/tyres combo.
Is this normal?

 

[Tom_16v]

Is it 5mph out throughout the whole speedo range.

I cant remember who it was who did a test, but theirs was a constant 2/3mph out from 10-100mph.

 

[Kev.]

All cars do this, my 172 over reads a little too. I think at 83 on the speedo is really 80 on my Snooper GPS.

 

[Tom_16v]

Most cars over-read, not under-read.

Manufacturers do this purposly so theyll never get blamed by someone caught speeding blaming it on speedo error.....

 

[Rich-D]

Quote: Originally posted by CocoPops on 26 January 2004

I fitted my origin b2 over the weekend and discovered that my speedo over reads.

Yeah mate, near as damn it every car on the road overreads...

 

[007]

Some GPS devices arent that accurate - that could be why - I doubt the Origon is designed to measure you exact speed. Just your where-abouts.

Speedos usually over-read on purpose as Tom has said.

 

[admob]

if you drive at a steady speed - say 80mph on the motorway then reset your trip computer, the average mph when it flashes up will read about 76mph which is what the computer thinks you are doing!!!!!

 

[blink172]

Is that why when you set the cruise control it flashes "80mph" the speedo rests at 83ish??

 

[Kev.]

Quote: Originally posted by blink172 on 27 January 2004

Is that why when you set the cruise control it flashes "80mph" the speedo rests at 83ish??

Mine does that too!

I can set Cruise control at say 81mph, my speedo reads 84mph and my GPS reads 80mph. lol

 

[KDF]

I did a test and posted up a picture of the GPS reading and Speedo reading, speedo said 60mph, GPS said 60.4mph It was out the same at 100mph but you try taking a picture at 100mph ..

 

[CocoPops]

Oh well, means I can get larger alloys and still have the speedo fairly accurate!

 

[cliopower]

i think it is law that they are not allowed to under read your actual speed.

 

[Daz]

I generally worked out the Origin may read just below what you are doing.. so when its beeping and you slow down, you DEFINETLY are going slower than the limit.

 

[wackojacko]

Why do you think i was going so fast down 2 Bluewater!!!

I dont use my speedo on the motorway, reley on the Angel instead.

 

[Moose1978]

Ive got a Road Angel and I read that they are supposed to be one of the most accurate things about.

The speedo always reads 4-5 mph more than what the ANgel shows.

 

[rt172]

Quote: Originally posted by _KDF on 27 January 2004

I did a test and posted up a picture of the GPS reading and Speedo reading, speedo said 60mph, GPS said 60.4mph It was out the same at 100mph but you try taking a picture at 100mph ..

Same on my car. Tried 2 different GPS units. Same results both times.

 

[clio sport]

Any of you guys know a cheap site to get the road angel from please?