accuracy of our speedo

[s1831559]

had a chance to hook up a sat nav in the car
pog's speedo shown 110km, but sat nav only abt 101km.
nearly out by 10km.
opinion guys?

[GT3]

is the sat nav dead accurate?

[brumue]

I get similar figures with my tomtom vs the car's speedo. The sat nav is more accurate.

Pretty normal as far as i know, from memory (of another post somewhere) VW if not all manufacturers set their speedos to read ~10% more at 100km/h. This is to cover their arses in case someone decides to sue them for providing an innacurate speedo resulting in a fine.

[anarchycamp]

yep all new VWs have this "feature"

[PeterHBne]

Latest Wheels Mag quotes and indicated 100 as being 93.

You can use your trip computer to check this. Pick an indicated speed, hold it, reset the trip and it will show what I imagine to be an accurate speed.

I find using this method and indicated 119/120 to be 110.

[insanekiwi]

92-93km actual on 100km / h reading on speedo

on

Garmin Nuvi 350 GPS
:-)

[Funkdancer]

My own speedo is out by about 8-9% as well.
I must admit I don't use the built in speedo much anymore; 1) I find it very hard to read, and 2) it's just too inaccurate at that. Around the 80-100kph range it's hopeless.

I rely on my sat nav calibrated Scangauge II when in tunnels, and that and the sat navs whilst driving.
http://www.vwwatercooled.org.au/newforum/upload/showthread.php?t=7075&highlight=scangauge

[DaveMack]

Well guys ... just think of all the bux you are saving. When you get caught exceeding the speed limit ... it won't be by as much as you first thought. :D

Dave

[ralphk]

Tyres 215/40/17 speedo reads 100 so does TOMTOM. Something else to try - set cruise at 110 reset trip computer and watch for the average speed....bit odd....or is the computer getting info from a different place then the speedo.

[Funkdancer]

Well guys ... just think of all the bux you are saving. When you get caught exceeding the speed limit ... it won't be by as much as you first thought. :D

Dave

Isn't it better to have perfect awareness of what you are doing wrt to the speed limit? I like to know if I'm driving exactly at the limit, or 2km/h over it - or 10 for that matter.

Just my personal preference I guess :) At least if I peg the cruise at the limit, I won't be holding up traffic travelling slower than the limit, I might hold up some otherwise speeders but then again might just save them some money.

[dilbert_rocks]

yep all new VWs have this "feature"

There are some other threads on this forum that mention the same thing. It may have something to do with the speedo not being linear (10k increments up to 100, 20k above that)?

Also, for those with Climate-Control, there are some other threads here that describe how to access the internal data via the Climate-Control panel (shows up where the cabin temp display normally is). This correlates well with my TomTom (which is what I use instead of the speedo).

Its strange however that the over-speed alert on the dash correlates with the speedo position instead of the digital data via the Climate-Control.

[Funkdancer]

10k increments up to 100, 20k above that

Is in fact 10k increments up to 80, 20k above that!

Completely useless... I drive through the Melbourne Citylink tunnel every day and it's got a fair few speed cameras. Limit is 80, and with the increment happening then and with the 10% issue, the speedo makes it near impossible to decipher what I'm actually doing. They really should have made the swap at 130 and upwards.

Not to mention that I also am using polarised prescription Ray Ban sunnies (fantastic stuff to eliminate glare (http://users.tpg.com.au/pschamb/pol.html)!) whilst driving @ day time. In the darkness of the tunnel, and with my sunnies, the blue lighting makes reading the actual speedo just about completely illegible.

No such issues in my Accord Euro which features much bigger dial, bright and clear types, with no funny scale swaps until getting into the serious end of the speedometer scale.

Sorry to sound like a broken record, but it's quite a bit weird user interface wise because conversely the Polo's mirrors are the best I've seen - with the convex design virtually eliminating the blind spot. My Euro's are severely limited here, in comparison.

EDIT: Speedos are out of focus, but these two shots really show off the difference nevertheless. I.e. you can almost work out the numbers of the Euro, whereas in the Polo it's just a blur.

http://www.vwwatercooled.com.au/forums/images/imported/2007/11/609736514_59b9ca3faf-2.jpg

http://www.vwwatercooled.com.au/forums/images/imported/2007/11/884763174_a936c9c8b5-2.jpg

[VW Convert]

Is in fact 10k increments up to 80, 20k above that!


On the Jetta the change in increments occurs at 100 KM/H, I find it very confusing, when I should be concentrating on where I'm going I find myself having to look closely at the speedo.

Cheers

George

[DaveMack]

On the Jetta the change in increments occurs at 100 KM/H, I find it very confusing, when I should be concentrating on where I'm going I find myself having to look closely at the speedo.

Cheers

George

One word, George ... Glasses. :D

Dave

[VW Convert]

One word, George ... Glasses. :D

Dave


Clever Dave, clever! :)

Cheers

George

[leasaunce]

i went for a long cruise yesterday on he Freeway, 400km both ways. set the cruise control to 100kph, but according to TOMTOM my actual speed is 92kph.(I even asked my mate, who was driving in front of me set his cruise on 100kph as well, his car the golf gti, STOCK)

Did 120kph on the speedo, but on Tomtom only 109kph.
So i tried low speed, 60kph on speedo, 57kph on tomtom.

is this normal on the gti? I've got this car brand new 2 weeks ago. everything is stock.

[VW GTI]

Yep.

http://www.cartoday.com/content/magazine/roadtests/pdfs/2006/12/01/poloVSfiesta.pdf

[Small_Fryz]

that would explain why every man and his dog was passing me when i was doing 110kph on the speedo in a 110kph zone.... and i sat on 100kph on the highway and every man and his dog was passing me then too....

Looks like i need to get a GPS of some sort to get correct indications

[firdausasri]

Any car speedometer will definitely overread, I'd say 8-10%. Using normal GPS (without differential) will not be accurate either because of signal and multipath issues. I've used a industrial spec GPS with Omnistar real time differential to test this issue, you'll see difference from 80km/h onwards

[VW GTI]

that would explain why every man and his dog was passing me when i was doing 110kph on the speedo in a 110kph zone.... and i sat on 100kph on the highway and every man and his dog was passing me then too....

Looks like i need to get a GPS of some sort to get correct indications

GPS costs more than getting your speedo recalibrated. But recalibrating the speedo doesn't tell you where to go. :)


Any car speedometer will definitely overread, I'd say 8-10%. Using normal GPS (without differential) will not be accurate either because of signal and multipath issues. I've used a industrial spec GPS with Omnistar real time differential to test this issue, you'll see difference from 80km/h onwards

I've had mine tested on a dyno. Wrong by around 5% all the way to 160. I've got 17s on mine so it's been corrected a bit.

[PeterHBne]

This is what I do. Get your trip computer to either the 1 or 2 setting (depending on whichever you don’t care gets reset often). Go to the average speed option. Pick a speed - say 100KMH indicated, hold on cruise control then reset the average speed setting using the reset button on the stalk and it will give you an accurate KMH reading. I find invariably, as mentioned elsewhere, indicated 100kmh is about 92-94kmhs actual and 110 indicated is about 102 actual. After a while you will get to learn what your actual speed is against indicated.

[Bubu]

I used a GPS (non industrial) to calibrate the speed on the Scanguage. Now I dont even bother looking at the speedo I just go off the readings of the Scanguage.

[nomodlowkmgti]

What rpm on the tacho is 100 gps speed maybe you can use a rev speed in 5th if it points to a mark as a way to do 100 real speed or is each polo a bit different.may be a formula to do with diff and 5th gear ratio x rpm to = 100.