speedo reading
 

Just bought a micro road pilot for my sti 53 plate and i cant believe the differance in speedo readings and the gps speed reading when the road pilot says 60mph the speedo on the sti says only 51mph :eek:

I thought a 10% + or - was the norm but this seems even further out god nows what it would be at 100mph

Any bobody else with gps systems noticed similar figures

At a constant velocity, my Origin Bluei is exactly the same as my speedo. Exactly.

My Origin Blue reads 5mph above the speedo at all times, but i have changed the clock face and forgot to mark exactly where the needle sat before i removed, so chances are its in the wrong place and just needs moving.

Not unusual for the speedo to read 5 mph over the actual road speed, 9 is more than I would expect at 60. Mine is about 5mph light to my GPS.

They can't afford for it to read under, imagine the claims 'my speedo said 30 when the Gasto said 35, its therfore Subaru's fault' !

Unusual for speedo to read under. If GPS says 60 i would expect speedo to read 60-65.

I run Navman GPS3450 and the speedo reading in various cars is always 5 - 7 MPH out so take from that what you want but I always go with the speedo in the car that im driving to be on the safe side and disregard my Sat Nav reading just in case.

Its Illegal for the spedo to under read, over read yes, not a problem.
I would try a different type of gps system, if its still the same, take the car back to subaru and ask (well demand) that its recalibrated.

Tony:D

My gps road angel says 60mph and my speedo says 65mph. Thats why your speed has a 10% tolerance with police while the road angel spec will tell you it can be out by only 1mph than actual readings!!!!! You will notice you can go through speed cameras by up to 10% of the maximum speed limit for that particular road.

on my bugeye the speedo was a constant 10% out all thorugh the range - both my road angel and b2 agreed which was nice... :)

mmm tried my m8s road angel in the car this afternoon and its the same as the micro pilot so i think im going to give my dealer a call on monday:D

At 140mph on the clock my origin said 140 as well (according to my passenger anyway)

On OE phase 1 and 2 classic cars a speedo overread of upto 8% is quite normal and on my own WRX 95 Wagon, when standard 150 mph was actually 136 mph.
Any change to tyres, wheel circumference, gearbox or diffs will alter the speedo reading.
For instance a car with 205 50 16 tyres may overread 8% but when fitted with 215 40 17 the overread will be even greater because, believe it or not, the rolling circumference of the 205 50 16 is greater than the 215 40 17.
This is why tales of 160 mph should be taken with a pinch of salt on semi-standard cars with a change of tyres or wheels.

On my 200sx this 'problem' was in built by Nissan and could be fixed by adjusting a potentiometer on the back. Anyone know if there is a similar adjustment to alter the scoobs speedo?

I have mentioned this before, But maybe the speedo is calibrated for 18 inch wheels running 225/40 rubber. as it is an option in the accesories list. Having it over read on 17`s is easier than recalibrating the speedo when you specify this option. I know mine over reads on my gps from work just waiting for a cable to see if it does the same on my PDA gps.

Mine is the same....my B2 reads about 5mph different to the speedo.....and i have standard wheels and tyres....

the gps is going to be spot on... normally the speedo over reads because if not and your doing 50 and the speedo read 45.. then the manufacturer will be liable..and they dont want that..do they...http://bbs.scoobynet.co.uk/images/icons/icon10.gif

My Road Angel is Constantly 3mph higher that the indicated speed
(MY05Sti)

In my 05 wrx on std wheels & tyres at;

30mph speedo, road angle 2 = 27mph
60mph speedo, road angle 2 = 56mph
100mph speedo, road angle 2 = 95mph
120mph speedo, road angle 2 = 115mph

< +5mph I don't think too bad, on par with mates Merc 220..!

You need to bare in mind for GPS to be accurate you maintain a constant speed.

What I've found is most speedos are either more accurate at middle speeds (~60 ish) and less at the extremes or more accurate an the extremes and less so in the middle.

Jason

Not true at all!!!!!

I was watching an episode of Road Wars a couple of weeks ago and on there was an interview with a traffic cop sat in his white mobile camera van somewhere in South Yorkshire. During the 2 hours of the interview/tv crew being there he had tallied up £16,000 of fines!!!!!!!!!!!!!

Now.... the relevant bit.......

The "safety camera" was set up catching speeders on a stretch of dual carriageway with a 40 limit.

The policeman gave a guided tour of the equipment he was using (laser sytem) an the trigger speed was..........................................

42mph

41 and you're ok...... 42 and....... Ticket!!! So if your spedo is out by that much 'the wrong way' in South Yorkshire..... you are pretty much goosed!!!!

The 10% plus 2mph tolerance is only a guideline. the actual tolerance used is down to the Chief Constable! They are now talking about introducing ZERO tolerance in Cleveland!!!!! Quick translation... #~@##@@#*(&%$^ = WE WANT MORE CASH!!!!!!!!

Paul

Quite right Jason... there is a time lag while the computer does it's math and catches up with you.... however something else to bear in mind is that for the GPS to give an accurate reading you also need to be going in a perfectly straight line. Any deviation from the straight and errors will start to creep in to the equasion

Paul

my sti is totaly standard wheels and tyres and is booked in this week to be checked:)

I use Tomtom 3 sat nav and the speedo reading is generally under by 5%.

it under reads because it has not ppp or remap, and they want you to think that it is still fast :D:D:D

Sorry Paul but i think your confused with what i said. If you go through a speed camera at 44mph on your speedo your actually doing approx 40mph. (This is what you'll see on your gps road angel) Speedos are usually out by 10% on the high side. This doesn't take into account if you change your wheel or tyre size etc.

Sorry alwong... I see where you are coming from now.... I thought you were refering to the tolerance guidelines of 10% plus 2 which people seem to think is a hard and fast rule when in fact it isn't, a tollerable 41 in a 40 limit is a 2.5% allowance!!

Cheers
Paul

BTW my TomTom Navigator on my HP PDA shows a difference of approx 4mph but the lag in the GPS catching up is far greater than it used to be on my Garmin GPS IV also speed accuracy drops off noticably on twisty roads.

My MY02 WRX speedo over-reads by 4 mph at 40 and 5 mph up to 100 mph on a private road.

Thereafter, it over reads by 8 or 9 mph, on an even more private road.....;)

Can the speedo be recalibrated????
 

I'd like to know if the electronic speedo on MY98 (STI4) can be recalibrated. It is WAY out - 12-15% I'd guess (speedo:60mph/Road Angel:52mph). I borrowed a Road Angel and was surprised by just how much it was out. I'm running on 205/50/16' at the moment, but will change to something like 215/45/18 - partly to 'up' the gearing (19mph/1000rpm - is a bit silly) and also to 'help' correct the speedo. Can these speedo's be recalibrated? There must be lots of people out there with imports who have the same problem.

My 01 Bugeye on 17"s reads 10% over all the way through the dial. Early sunday morning checked it again and took it to the top of the dial.

Private road BTW

dodgy speedo
 

Hi all had my wrx 01 bug eye for about week now and found it can be 5-10 mph above actualt speed limit!

Am delighted to hear its a fairly common problem lol

CHeers

Ross

The thread is only 7.5 years old you know? ;)
As long as your speedo doesnt over read (ie car says 30mph but actual speed is 31mph) you are ok (with in 10% of course ;))

Tony:)