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29K views 45 replies 16 participants last post by  nocusr 
#1 ·
I have a 2012 CC Lux Plus that came equipped with 235-35-19 wheels. The dealer replaced them with 235-45-17 at my request, which I realize are not alternate sizes for the Plus, but they are for the Sport. Without going into specific details, this was a good will gesture by my dealer; the car having been back to them 5 times for radio/navi issues and wheel alignment problems (was a demo, driven by the general manager). Also, the 35 series tires are a poor choice for the pot hole laden NJ highways. The car rides fine, with minimal change in handling, but I noticed my speedometer reads 3 mph higher than actual speed as compared to the speed indicated on my portable gps. Reading numerous websites, the gps speed is supposed to be accurate. Compensating for the new tires, which are only .2" smaller in diameter (.63" difference circumference) the speed difference should be only .6 - .7 mph, using the calculator on the Palo Alto Speedometer Inc. website http://www.paspeedo.com/calculator.htm . I've also read that the 3 mph difference is actually a "standard". Does anyone know if the speedometer can be adjusted, even if it has to be a dealer adjustment? VW is very reluctant to give out any technical details when I've asked them in the past. You wouldn't believe what I had to go through to get a fuse panel layout!
 
#2 ·
Nocusr,

I've also found my speedometer to be off by about 3 to 4mph at 70mph. We have the factory 18s and our's is on the low side so at posted 70mph we are really doing 66 to 67mph. I find it frustrating to have a gauge / instrument that is not accurate. Please let us know if you find an answer to the re-calibration issue.

John
 
#4 ·
Same issue with my 2012 Lux Plus. Factory 18s. Pass a roadside radar every morning that flashes red when you go over thirty. Radar is reading thirty and speedometer is reading 33 or 34 consistently.
 
#5 ·
My 07 rabbit was off the same amount you guys describe. My '12 jetta is DEAD accurate at all speeds up to 100. Haven't gone faster than that to prove. My speedo lines up EXACTLY with GPS and roadside radar.
 
#7 ·
Same here. 2011 Lux Plus, set cruise at 70, speedo says 70, GPS says 66. I don't mind speedo being a little high, but your odometer and speedo are connected. If the speedo is reading to high, chances are it's because the car thinks it has travelled farther in a given time period than it really did (or of course VW cannot make an accurate internal clock, which is unlikely).

This means your odometer's reading is falsefully high. You lose your car's value faster. Your warrenty runs out faster too.

We need to make a fuss to VW. Honda had similar issue. They had to give several thousands of miles extra on warranty.
 
#8 ·
It's not entirely uncommon for speedo to read a little high. This is because every meter has a tolerance. Because of the liability issue, the OEMs don't want the speedo to read too low. Otherwise they could be responsible for speeding tickets or even accidents. So they put all the error on the high side, the tolerance of the meter is something like -0/+x. That's why speedo often reads high.

But 4MPH is too much.
 
#9 ·
I have a 2012 CC R-Line with factory 18's with the same 3-4mph speedo difference and the dealer says there is nothing that can be done to correct this, has anyone had this condition resolved?

This is our first VW after dirving Honda's for 25 years and we love the car but this speedo calibration issue is annoying.
 
#10 ·
I think we should all call Volkswagen of America and complain and maybe they will extend our warranty some because this I causing our odometers to read in accurately
 
#13 ·
I called VOA Today and they told me they allow for. 4% difference and it can be influenced by a number of things like wheel size friction and temp..still sound like BS to me but anyways they said the odometer isbt affected by the speedo being off because the odometer gets its info from Wheel RPMs...but so does the speedometer so wtf VW!
 
#16 ·
Yea on the old cars. They get a vss signal from each individual wheel, but mainly the two front wheels. But still if it was off of the trans and its reading wrong....its still reading wrong. And different size tires will affect the vss.

Sent from my bum using Tapatalk
 
#18 ·
It's pretty easy to confirm whether or not the odometer is affected. If you have a portable GPS, reset the GPS tripometer before you head out on a trip. Reset car's tripometer too. At the end of the trip, compare two numbers. If they are different, that's solid evidence that the odometer is affected. GPS is very accurate. Even 5% difference warrants a challenge to VW (5% of 36,000 miles is 180 miles).

VW may argue that one GPS has random error, but if we can each make a test and present the difference with different GPS, that'll be enough to convince a judge in federal court.

If you wonder where the GPS tripometer is, for Garmin brand, from the map page, hit the area where it shows your speed at lower left corner, you'll go to that screen wherein speed, tripometer are shown.
 
#20 ·
Will have to try this on my Geek Mobile as the speedo is off.

5% of 36000 is 1800...
 
#22 ·
If they say 4%, then we can compare GPS against speedo at 20 mph. If we can show that at 20MPH the difference is more than 1 mph, then they are out of spec and have to do something. Otherwise I will write to NHTSA to twist their arms. Recalibration can be done, it's just a lot of work. They can reflash the speedo software to fix this, they just don't want to do it.
 
#23 ·
What I don't understand is that it doesn't affect every model.

I've had three new beetles for work (04',05',10') which all had their speedometer off.

The speedometer on my rabbit (08') is perfect though.
 
#24 ·
My speedo is off 4-5mph based on gps comparo. It doesn't bother, though. I still know how fast I'm driving. The bottom line is that people think it's a problem because everyone has gps nowadays. If they didn't, this would not be an issue.
 
#27 ·
I think it's at all speeds but then again, I don't really check to see if the speedo is off when I'm going 20mph. I'm not going to get a ticket at that speed. If the speedo were reading a slower speed than I was actually going, I would have issue. As it is, it doesn't bother me since it's the other way around.
 
#28 ·
In my experience, the variance is more the faster you go.
 
#29 ·
Mine (2012 CC) is definitely off 4 mph at 30 mph. It definitely does seem to be off by more the faster I go. My speedo has read 85 on the highway and I was being passed by virtually everyone.
 
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