I have a 2007 Azera and a 2007 Santa Fe and I agree. With my Garmin Nuvi 350 the speedometers are both about 5% slow compared to the GPS.

 

I have noticed that my Garmin GPS reads 2 mph slower than the speedo. This is less than 1%; pretty acceptable in my book.

 

Same here My SF 2007 does the same. 5% approx.

 

Well, the problem is that if I sale the car at say 48000 miles, it's going to say 50500 which might lower its resale value, and it even shortens the 100000 miles warranty to 95000.

More measurements:

GPS  Car (MPH)
40   38
60   57
75   71

 

Not a big deal for your actual speed to be a bit lower than what the speedo reads but if it's faster that is a problem. I would demonstrate that to dealer and have them recalibrate it.

Checked mine with my Garmin c550 and my car is about 2-3 mph slower than speedo reads i.e. car shows 65mph actual is 63mph.

 

Here's a link to a GPS site that also dealt with this issue . . .

http://www.gpspassion.com/forumsen/topic.a...=speed,accuracy

 

Using a Scan Guage II shows my speedo to be up to 9KM/Hour too optimistic - that is too fast.
This suggests that it's the meter itself that's out of tolerance, not the sensors.

 

Thanks for the link Redryder. At least it appears that every manufacturer does it to play safe in the 0 to +10% error margin. I think which ever law specifies that error should be more strict like something between 0 and +3%.

Maybe they are going to start to put something like the side view mirror's "Objects in mirror are closer than they appear", like "Actual speed might be slower than this reading". :w00t:

 

"Well, the problem is that if I sale the car at say 48000 miles, it's going to say 50500 which might lower its resale value, and it even shortens the 100000 miles warranty to 95000.

More measurements:
CODEGPS Car (MPH)
40 38
60 57
75 71"

Both my GPS & scangauge show my speedometer to read 1 - 2 kph high which is approx. 1 mph. Most of my motorcycles have read 7 - 10 % high so I'm happy with the accuracy of my Santa Fe. You may want to check your odometer, mine have always been accurate even though the speedometer is off.

 

er...Is that true?

My car runs at 10% higher speed than my GPS. always. bang on 10% eg. GPS says 50mph car reads 55mph.

I had never really correlated that the mileage would be linked to speed?? Is that true or are you having a laugh??

My warranty is 5 years/unlimited mileage so It doesn't really bother me, unless I am being conned on my servicing??

 

Same here. Speedo reads 5% higher than GPS.

 

I have no idea if mileage is also wrong or not. It would have to be tested on a long trip to get an accurate result.

 

You can use mile markers on any highway. Measure a few times and see if you get a consistent difference.

 

For us who has gps we can calculate it with it too.

 

My speedo reads about 4 - 5 kph faster than actual at highway speeds. I'd say that the PCM is conservatively calibrated with the 18" wheels which are just slightly taller than the 16" wheels. This would give you a faster-than-you-are-going reading.

When I have to replace the tires next summer I'm going to a 255/65-16 which is a bit taller and should reduce my misreading.

Stewart

 

Sad but true... as nearly everyone has stated the speedo is overoptimistic but if you read the speed off the on board diagnostics port it is bang on. Hrmmm....?

The black box knows, why doesn't the speedo?

 

Good to know the black box isn't off.

Cheap speedo or conspiracy from Hyundai?

 

I tested my speedometer on my 2007 Fe SE and found the speedo was 2mph higher than the GPS which is acceptable to me. My wife thinks it is good to save you speeding tickets. Fred.

 

Seems to me that +5% speedometer error could be easily caused by anything which reduces the outer tread diameter by 5%, such as a combination of tread wear and underinflation.

Regarding the warranty conspiracy theory, there would be very little for Hyundai to gain by cheating people out of 5% of their warranty. The court costs alone would see to that. By contrast, however, just imagine what would happen if some lawyer ever figured out that their vehicles were UNDERstating speed... suddenly you've got TV commercials promising big payoffs for any **** who rolls a Hyundai.

 

I have found similar differences (speedo reading 2-4mph higher than GPS) on two of my previous cars that I tested (BMW and Skoda). I haven't tested it on the Hyundai yet but I expect it to show the same sort of difference.

I've read unverified reports that, in the UK at least, speedometers have to read 0 to +10% of the actual speed by law. This is to ensure that people always drive at the real speed limit or slightly slower if their speedometer needle is on the speed limit.

I haven't checked the odometer but I would expect this to be more accurate than the speedometer as there aren't safety implications with a slight underestimate of mileage.

 

imagine how much off the speedometer is in a car that has its tires inlflated to 45-50 or more psi.... :whistling:

 

You would think that... but then again.

http://www.hondaodometerclassaction.com/


If you tap any kind of diagnostic tool into the on-board diagnostics, it'll spout back the speed very accurately. Why does the hidden black box ECM report a truer speed/distance than the driver's speedometer/odometer?

It's not a tire wear thing. A 5% change in tire diameter would mean a change of about 1½" in diameter. Who has ¾" of extra tread on their tires?


The speedometer and warranty linked odometer should be fairly accurate. They aren't.


I'd imagine everyone that likes the "safety" of an optimistic speedometer also has the kitchen clock set 5 minutes ahead so that they make it to work on time... hehe

 

Originally posted by looney@Mar 18 2008, 10:42 AM
imagine how much off the speedometer is in a car that has its tires inlflated to 45-50 or more psi.... :whistling:

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It would actually make it more accurate, but unfortunately radial tires don't balloon.

 

Originally posted by UniR@Mar 18 2008, 02:04 PM
It would actually make it more accurate, but unfortunately radial tires don't balloon.

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you are so clueless

 

Originally posted by UniR@Mar 18 2008, 03:02 PM
It's not a tire wear thing. A 5% change in tire diameter would mean a change of about 1½" in diameter. Who has ¾" of extra tread on their tires?

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Maybe not 3/4", but 1/2" is certainly possible. That's about 3% error. Now drop the pressure a few psi and you've easily got 5% error.

A quick Google search reveals that overzealous speedometers are quite common, however, even with factory-spec tires. I checked the Garmin yesterday and sure enough my Santa Fe's speedometer is about 3% optimistic. That explains why I am always late