Is it me or my speedo is weird...

[edstergtsport]

I got my TSI GT Sport now for almost one week now. I LOVE it! I pretty much have no complaints about it just yet. Car handles great, DSG is spot on, great power, and comfortable to drive. Pretty much even exceeded my expectation since the test drive. However i noticed from few days ago since i started driving on the freeway I noticed something strange.
I am no speed demon but i am no grandma either. I usually set on cruise control at about 100-105 km/h in 100 zone unless overtaking. however i noticed atleast 85% cars are overtaking me, cars infront of me seems to pull away further and further, feel like i am cruising at a different speed to everyone else.
and an started to notice that on even when i am not on freeway. 50 zone, 60 zone, 70 zone and 80 zone. Everywhere i go cars are overtaking me when i am thinking i am going at the limit! It never happened to the Toyota Avalon and Camry and 1990 Mitsubishi Magna...
So is there a way to find out if my speedo is off? or its everyone on the road likes to speed.
If its off is there a way to correct this problem?
I know its not a major issue since it may save me a few speeding fines but it sure is annoying watching most cars so close to my rear and than overtaking me giving me that "grandma stare"

[TDI Dude]

I got my TSI GT Sport now for almost one week now. I LOVE it! I pretty much have no complaints about it just yet. Car handles great, DSG is spot on, great power, and comfortable to drive. Pretty much even exceeded my expectation since the test drive. However i noticed from few days ago since i started driving on the freeway I noticed something strange.
I am no speed demon but i am no grandma either. I usually set on cruise control at about 100-105 km/h in 100 zone unless overtaking. however i noticed atleast 85% cars are overtaking me, cars infront of me seems to pull away further and further, feel like i am cruising at a different speed to everyone else.
and an started to notice that on even when i am not on freeway. 50 zone, 60 zone, 70 zone and 80 zone. Everywhere i go cars are overtaking me when i am thinking i am going at the limit! It never happened to the Toyota Avalon and Camry and 1990 Mitsubishi Magna...
So is there a way to find out if my speedo is off? or its everyone on the road likes to speed.
If its off is there a way to correct this problem?
I know its not a major issue since it may save me a few speeding fines but it sure is annoying watching most cars so close to my rear and than overtaking me giving me that "grandma stare"

More than likely everyone on the road just likes to speed!! However I do know that there are new ADR's in effect, which started sometime this year, bascially it stated that speedo's must only be within a 10% tolerence. ie: if doing 100km/h is allowed to show anywhere between 90km/h to 110km/h, nearly all manufacturers will understate the speedo reading to some degree so as to not be open to massive lawsuits from people claiming they were caught speeding incorrectly and to avoid bad publicity. The only ways to check your speedo accuracy is either take it to a speedo specialist who can see if it is calibrated correctly or if you have a GPS Navigation toy you can use that to calculate your speed over a given distance, though this may also be out by a few km's. In the end I wouldn't worry too much about it personally and here in NSW the police are a lot more leinient than in other states such as VIC.

[DaveMack]

Most new VW speedos under-read by about 7-9%. Designed that way as per TDI Dude's post.

Dave

[GermanwithaVdub]

mine is up around 10% optimistic depending on tyre wear

[edstergtsport]

I just read something about the Climate Control Codes trick to get the digital speed reading... tested my speed down Burwood Hwy a few minutes ago, speedo says 50 the climate control says 46, 60 climate control says 55, 70 climate control says 64, 80 climate control says 72-3, 100 climate control says 92... no wonder everyone was over taking me on the freeway.... need to be about 108-110 on speedo to be 100 on real life.... Anyway sorry to everyone who i held up on the right hand lane on Eastern Freeway (i saw a few GTIs overtaking me)... i really thought i was going 110...

[broady69]

I used the climate control to check my actual speed and the speed indicated by the climate control was identical to the speed on my GPS and as such I managed to find the correct speed versus the speedo reading. At 110 km/h my speedo is reading 124km/h and 50km/h is at 58km/h.

Use it to check your settings.

Here's how:

1. Hold down "A/C" button, and press the "up vent" (next to recirculate). Both temp displays will read 00 or 00 0, and you can release the buttons once they do.

Turn the left temperature knob clockwise until it reads 19 0.
Turn the fan knob until the temperature reads 19 1.
The right temp display is now a digital speedometer!

To exit, press the "a/c" button again.

You can also use this function to check the following:

This is what the rest of the numbers mean

Main channel: 0 - System data
0 Number program
1 Left ERL
2 Skillful ERL
3 Point of job accensione/avvio
4 I recirculate automatic rifle (motor)/I recirculate automatic rifle Bit
5 Heating from active detention
6 Air Quality (7 = fresh air)
7 Deriving
8 Acronym country
9 Sensor zone head

Main channel: 1 - UIF
0 Inner temperature (°C)
1 Surface Temperature (°C) (I think it means external)
2 Temperature piastrine in platinum (°C)
3 Corrector piastrine in platinum (°C)
4 Uif-Sonnenint
5 Corrector radiation (°C)
6 dynamic corrector (°C)
7 OrrettoreC I recirculate (°C)
8 thermal corrector (°C)
9 Compensation ignition (°C)

Main channel: 2 - Sensor radiation SX
0 Radiation not delayed (W/m2)
1 Corrector radiation for regolator temperature (W/m2)
2 Corrector radiation for impeller (W/m2)
3 Value TO

Main Channel: 3 - Sensor radiation DX
0 Radiation not delayed (W/m2)
1 Corrector radiation for regolator temperature (W/m2)
2 Corrector radiation for impeller (W/m2)
3 Value TO

Main Channel: 4 - External Temperature
0 External temperature (°C)
1 Temp. External line CAN (°C)
2 Temperature inhaled air climate (°C)

Main Channel: 5 - Theoretical temperature SX
0 Theoretical Temp. air in escape SX (°C)
1 Theoretical difference between temp. and temp. effective (°C)
2 Value regulation the sx. (½% )
3 Pi-Stell-Max (½%)
4 Defrost SX

Main channel: 6 - Found temperature SX
0 Temp. Found SX (°C)
1 Temp. Feet SX (°C)
2 Temp. Facade SX (°C)


Main channel: 7 - Theoretical temperature DX
0 Theoretical Temp. air in escape DX (°C)
1 Theoretical difference between temp. and temp. effective DX (°C)
2 Values of regulation regolator (½% )
3 Pi-Stell-Max (½% )
4 Defrost

Main channel: 8 - Found temperature DX
0 Found Temp. air in escape DX (°C)
1 Temp. Feet (°C)
2 Temp. Facade (°C)

Main channel:9 - Theoretical temperature evaporator
0 Theoretical temperature evaporator (°C)
1 Theoretical difference between temp. and temp. effective evaporator (°C)
2 Values of regulation evaporator (5mA/Dig)
3 Modality Regolator evaporator (you see under)

Main channel: 10 - Effective temperature evaporator
0 Effective temperature evaporator (°C)
1 Pressure coolant climate (bar)
2 Medium temperature coolant climate (°C)

Main channel:11 - Climate control compressor
0 Power theoretical electrical worker
1 Power effective electrical worker
2 Power electrical worker max
3 Kompressor PWM (0... 200) (Dig)
4 Power electrical worker offset compressor
5 Values power electrical worker
6 Code disinserito compressor (you see system)

Main channel:12 - Climate control impeller
0 Theoretical tension of the electric impeller (V)
1 Manual regulation
2 Code anomaly
3 Reduction impeller (V)
4 Impeller offset (0.1V)

Main channel: 13 - Temperature bocchette air SX
0 Formattato theoretical value (%)
1 Real theoretical value temp. Bocchette sx.(Dig)
2 Confirmation el. temp. Bocchette sx (Dig.)
3 The maximum limit temp. Bocchette sx. (Dig)
4 Limit min. temp. Bocchette sx. (Dig)

Main channel: 14 - Temperature bocchette air DX
0 Formattato theoretical value (%)
1 Real theoretical value temp. Bocchette dx (Dig)
2 Confirmation el. temp. Bocchette dx (Dig)
3 The maximum limit temp. Bocchette dx (Dig)
4 Limit min. temp. Bocchette dx. (Dig)

Main channel: 15 - Piedi/centrale temperature bocchetta
0 Formattato theoretical value (%)
1 Real theoretical value temp. Bocchetta centers them (Dig)
2 Confirmation el. temp. bocchetta centers them (Dig)
3 The maximum limit temp. bocchetta centers them (Dig)
4 Limit min. temp. bocchetta centers them (Dig)

Main channel:16 - Defrost Shovel
0 Formattato theoretical value (%)
1 Theoretical value real Defrost shovel (Dig)
2 Confirmation el. Defrost shovel (Dig)
3 Limit maximum Defrost shovel (Dig)
4 Limit min. Defrost shovel (Dig)

Main channel: 17 - Shovel I recirculate inner
0 Formattato theoretical value (%)
1 Theoretical value real shovel I recirculate (Dig)
2 Confirmation el. shovel I recirculate (Dig)
3 Limit maximum shovel I recirculate (Dig)
4 Limit min. shovel I recirculate (Dig)

Main channel: 18 - Shovel cold air
0 Formattato theoretical value (%)
1 Theoretical value real Shovel cold air (Dig)
2 Confirmation el. Shovel cold air (Dig)
3 Limit maximum Shovel cold air (Dig)
4 Limit min. Shovel cold air (Dig)

Main channel: 19 - Data Motor
0 Vehicle velocity (km/h)
1 Vehicle velocity (Mph)
2 Motor temperature (°C)
3 Engine speed (RPM)
4 Air con compressor speed (RPM)

Main channel: 20 - Data sent by CAN
0 Additional heating (upon request) (1 = on)
1 Confirmation el. PTC (1 = on)
2 Power el. effective PTC
3 % air demanded from radiating climate (%)
4 Relationship % of radiating peak air (%)
5 No performance demanded to the disp. of heating (1=no performance heating)


Main channel: 21 - Ripartitore of air Climate
0 Defrost (%)
1 Facade (%)
2 Feet (%)
3 Bocchetta areazione (%)
4 I recirculate fresh air/cleaned up (+ bocchetta...) (%)
5 Appraisal sensor (%)

Main channel: 22 - Data timer
0 Period of pause (min)
1 Motor operating time (sec)
2 Operating time with inserted key (Sec)

Main channel: 23 - Special channel
0 Sensor inner lighting system (Dig)
1 Air quality sensor

Main channel:24 - Version software
0 Development state
1 Software version
2 Type SW
3 Keep Frozen (0/1 = Values of refrigeration come maintained ad.eccezione.della Diagnosis )
4 Version K Matrix
5 EEP- Testflags
6 It codifies Vag (2)

Main channel: 25 - Test channels
1 - 9

Main channel: 26 - Parameters for surveys on crystals
0 Delay (sec)
1 Passo/udm (digit)
2 The minimal limit (digit)
3 Limit max. (digit)
4 Passo/udm on HellaKit

Main channel: 26 - Bocchetta direct areazione
0 Formattato theoretical value (%)
1 Theoretical value real Bocchetta direct areazione (Dig.)
2 Confirmation el. Bocchetta direct areazione (Dig.)
3 Limit max. Bocchetta direct areazione (Dig.)
4 Limit min. Bocchetta direct areazione (Dig.)

Main channel: 28 - Umidita
0 Theoretical Umidita (%)
1 Relative Umidita on temperature UIF (%)
2 Temp. Crystals WSS (°C)
3 Temperature condensation point (°C)
4 Difference temperature of the melting point (°C)

Main channel: 29 - Crude values umidita
0 Temp. Crystals, corrected (°C)
1 Temp. Crystals, not corrected (°C)
2 Sensor umidita (%)
3 Temperature sensor (°C)
4 Temperature condensation point (test measure) (°C)
5 Code anomaly

Main channel: 30 - Values indicated to you umidita
0 Value sensor termofilo (Dig.)
1 Temperature rif. termofilo (Dig.)
2 Periodic duration umidita (10 (to the power of -4) sec)
3 Temp. Reference umidita (Dig.)
4 Umidita Rel. on the sensor (%)
5 Temperature sensor umidita (°C)
6 Temperature crystals (not corrected) (°C)

[edstergtsport]

Thank broady69 THATS alot of interesting functions there! I GOTTA check them out!

[Splashalot]

....however i noticed atleast 85% cars are overtaking me, cars infront of me seems to pull away further and further, feel like i am cruising at a different speed to everyone else.

Hooray, seems I'm NOT going mad! I've noticed the exact same thing in my MY08 GTI.

Thanks to Broady I'll be checking my speedo accuracy tomorrow.

Kind-of raises the question, though: If the CC is capable of showing accurate speed, why not the speedo?

SS

[GermanwithaVdub]

Kind-of raises the question, though: If the CC is capable of showing accurate speed, why not the speedo?

SS

for the reasons mentioned above, it is a deliberate act to ensure that tyre wear does not make the speedo wrong the other way and so that they dont end up with any law cases

[Splashalot]

for the reasons mentioned above, it is a deliberate act to ensure that tyre wear does not make the speedo wrong the other way and so that they dont end up with any law cases

Except tyre wear will result in more wheel revolutions for a given speed - meaning your speedo will read even faster relevant to the actual speed - and probably outside the 10% allowance under ADRs. I can't see any valid reason why VW don't make the speedo (more) accurate in the first place - most other makes do.

SS

[GermanwithaVdub]

Except tyre wear will result in more wheel revolutions for a given speed - meaning your speedo will read even faster relevant to the actual speed - and probably outside the 10% allowance under ADRs. I can't see any valid reason why VW don't make the speedo (more) accurate in the first place - most other makes do.

SS

ah yes that is true... didnt actually think about it before i made that comment my bad

[ozgriff]

It is bitterly disappointing that VW have chosen the speedo to be around 7-9% out - I thought I was flying along keeping up with traffic until I realised it was my speedo that was lying. C'mon, this is a crucial part of the car and I'm guessing what speed I am really going.

When I queried the speedo readings with my dealer, they said it was within the acceptable range. My acceptable range is 2-3% so I'm not a happy jan with this one.

This is like setting your clock forward by 10 mins, there's really no point, I'd rather know the right time and use accordingly, than an artificial adjustment.

I do understand the point that I wouldn't want the speedo to read slower.

[The_Hawk]

Tyre wear shouldn't be that much of an issue and it gets smaller and smaller as your wheel gets bigger and bigger (depending on tread depth).

Example.

Say you have an 18" Rim + say 8cm of tyre, that makes the diameter equal to:

18*2.54 + 2*8 = 61.72cm

Now the circumfrence (sp?) would be 2*3.14*61.72 = 387.6016cm

Say your tread is 1cm deep, that means a FULLY WORN tyre has a diameter 2cm less than a new tyre:

2*3.14*(61.72-2) = 375.0416cm

Now 375.0416/387.6016 = 96.76%

So we can see the difference is only 3.24% so thats all the speedo should be out, but lets test anyway:



Now given that the speed is basically a function of wheel revolutions / min expenaded out to give a km/h...

If a wheel spins 2,579,968.7 @ 100km/h when new and the speedo was right, then at the sames revs a worn tyre would spin the same number of times, but wouldn't have travelled as far...

So 2,579,968.7*375.0416 = 967,595,589.19792cm or 96.76km again a difference of 3.24% from the base score.


To look at it the inverse way, to be *actually* travelling at 100km/h with worn tyres, your speedo would have to read 3.24% different, or 103.34km/h (100km / 96.76%).



So really long story short, your speedo should start to read SLOWER not faster as your tyres wear. So if your speedo was right in the first place you should never be able to blame the maker for anything. The only thing I can think of is that the car potentially comes with different wheels which are slightly larger, hence the difference. But then you would think that it would be possible to just set something via VAG-COM to fix that. (Maybe you can anyway).

For interest, if you make the wheels bigger and retain the same 1cm tread deapth, then the worn size vs new size becomes smaller and smaller a difference. Also for reference, if I substitute in a 2cm tread depth, it blows the difference out to 6.48% or 6.5km/h @ 100km/h indicated. But how many tyres have 2CM wear in them....

Oh, and BTW, my Mk3 is pretty much dead on accurate. More by pure coincidence I would suggest

[richardnau]

There are a number of threads on this subject over at GolfMkV.com. Interestingly, a number of MY08 owners have reported that in their cars, the speedo reads very accurately (within a percent or two of actual). I'm still waiting for my MY08 car, so I can't attest as to the accuracy of the statement.

I'd be wary of assuming that any reading from the climate control unit is more accurate than the reading from the speedo (though it may be DIFFERENT!) -- they are both subject to the same errors: wheel circumference (varies with wheel size, tyre aspect ratio, tread depth, etc.) and calibration. They could both be wrong as easily as they are right!

To be sure as to how accurate a speedo is, time the vehicle over a known measured distance or use a GPS system (at constant speed). I know that when I do eventually receive my car, I'll be testing accuracy with a Garmin GPS -- sitting on a nice flat road with cruise control enabled...

[TDI Dude]

I was on the understanding that speedo readings were taken from the gearbox not the rim/tyre? So therefore would tyre wear be irelevant to speed calculations? Just throwing it out there..