# VW Speedometer Accuracy



## buckboss (Apr 17, 2010)

Our 2011 Golf (Jetta in USA) TDI Wagon arrived this week. Automatic. 16 inch wheels. I tested the speedometer against the GPS readings for speed and the VW was 6% to 7% less than the GPS over a wide range of highway speeds. The GPS has been tested as accurate with two other vehicles. Do you think this is an acceptable variance? Can the speedometer be recalibrated by the dealership. Anyone else have similar results?


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## Boogety Boogety (Jun 22, 2003)

Yes.
Yes.
Yes.

All VWs (and most other Euro cars) show a speedo speed below the true speed. Usually 3-4mph low at 55-60mph. :what:

I say "yes" but the answer is "probably." Some may not want to deal with it, some may not know how. regardless: It's not a warranty issue, so there will certainly be a labor component you will pay for. 

Yes. Every VW, BMW, and MB I've ever owned has had the same issue. :banghead:

You could always remove the needle and replace it 2°-3° up clockwise, and let that be the end of it... :laugh:


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## GTINC (Jan 28, 2005)

Boogety Boogety said:


> .....All VWs (and most other Euro cars) show a speedo speed below the true speed. Usually 3-4mph low at 55-60mph....


All commercially produced vehicles will have speedometers that read high, not just VW or European ones. As a practical matter, the setting has to be high to account for tolerance variation in the gauge, and primarily the tires. No manufacturer can afford to individually calibrate each vehicle as it leaves production.

No vehicle can be allowed to leave production reading low. 

This is not some new situation and is only an "issue" because folks can now see the difference compared to their GPS. And, having the speedo read high is not a real problem, just something folks like to complain about.


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## Boogety Boogety (Jun 22, 2003)

> All commercially produced vehicles will have speedometers that read high,... No vehicle can be allowed to leave production reading low.



True that. But... :what:

_*d=rt*_

where distance = rate (speed) x time

In forty-plus years of car ownership, I can probably count on one hand the number of factory-equipped American cars that had speedos that weren't dead on. For years and years, some highways and even secondary roads had calibrated stripes at 1/10th, 1/4, 1/2, 3/4, and one mile distances, or "speedometer calibration" segments for the same purpose. Even the highway mile-markers are pretty accurate... so it's always (even pre-GPS) been really easy to check the accuracy of your speedo using those methods (precisely 60 seconds per mile @ 60 mph between lollipops, e.g.). It's something I've done for years as a mental exercise on long drives. Invariably, the same segment would take a few seconds more at a steady 60 in every one of my Euro cars, showing a slower true speed than the gauges claim. Try it sometime...


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## GTINC (Jan 28, 2005)

Boogety Boogety said:


> .....In forty-plus years of car ownership, I can probably count on one hand the number of factory-equipped American cars that had speedos that weren't dead on...


I believe you think that was true, but it may be more an indication of you memory than reality. I am sure that speedometers where individually calibrated in the early part of the century, but this is certainly not practical now. Also, there was much less variation in type/sizes of tires available up until the early 60s.


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## Boogety Boogety (Jun 22, 2003)

> I believe you think that was true, but it may be more an indication of you [sic] memory than reality. I am sure that speedometers where [sic] individually calibrated in the early part of the century, but this is certainly not practical now. Also, there was much less variation in type/sizes of tires available up until the early 60s.


No, I don't _think _it was true, it _was _true, and remains so. If anything, the switch from mechanical to by-wire speed sensing protocols would make it _much _more "practical" (I think you meant "easier") to calibrate a speedometer now than before. It would just take a couple of lines of changed code, instead of swapping out tiny gears to achieve greater accuracy. :banghead:

I'm not a fan of American Iron, but I've owned my share, and I stand by my "memory" of their performance and capabilities, as well as that of their European brethren. Your uninformed statement above can't be backed up by your own personal knowledge and experience, can it... ? :screwy:

For instance: By "in the early part of the century," did you mean the 20th Century (1900-1949), or the 21st (2000-present)? Or did you mean, from "the 60s?" Your mention of "much less variation in type/sizes" of tires during any automotive period seems to ignore the many options available to buyers throughout the Baby Boomer automotive era. Back before option "packages," you could order a car as a "hot-water 6" (an optionless, base car, with a 6-cylinder engine, and a heater as the only option) or add individual options one-at-a-time, not bundled (power windows only _with _power locks _and _power mirrors, for instance). The many choices in wheels and tires back before the '80s would drive a current buyer to drink (and back then, no open-container laws, so you could indulge on the way home if you so dared). In the '80s and up, as a cost-cutting measure, _reduced _option packages were introduced, and with them, lesser tire-wheel combinations. There are _far _fewer choices available to OEM buyers now, than back in the day. :laugh:

When you own and drive some 100 cars, and have experience with them, _then_ you can provide us with authoritative experiences. Until then, you're just guessing. So, good luck, I'll wait...


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## buckboss (Apr 17, 2010)

*Speedometer Feedback - thanks for the input*

Thank you Boogety Boogety and GTINC for your informative and spirited feedback about factory settings for speedometers and VWs in particular. I did smile at the suggestion to rotate the needle clockwise a degree or two.

I will accept the factory reading and make driving adjustments according to traffic and conditions etc. with no further complaints.

The Golf Wagon TDI is really fun to drive. We have had it less than a week but so far we are impressed with the fit, finish, features, handling, and the transmission. 

Looking forward to a long trip to test the fuel consumption.


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