Speedometer reads 2-3 MPH faster than actual
05-19-2018, 04:11 PM
#1
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Speedometer reads 2-3 MPH faster than actual
I'm driving an S5 Cabrio and every time I go past a speed-trap meter on the side of the road the speed it shows is always 2-3 MPH slower than what my speedometer shows, meaning that my speedometer is showing my speed as 2-3 miles faster than I'm actually driving. I thought I was imagining things, but tested these same radar traps with other cars and it measured each one exactly the same as the car's speedometer showed. So during my recent maintenance visit at my Audi dealer I told them about this problem assuming that this would be an easy adjustment. To my surprise, the answer that came back was that Audi is aware of this issue, and in fact, it is not an issue since my model is intentionally programmed this way so there is no "fix". I don't know if this applies to all S5 or A5 models, but it surely applies to S5 Cabrios. The good news is that it might save me from a speeding ticket someday, but I still think it is a rather strange setting. Has anybody had the same experience?
05-19-2018, 04:33 PM
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The few 'show your speed' radars I've driven by have either shown my exact speed, or it will display 1 MPH slower than what I am driving. Don't recall ever seeing 2-3 MPH slower though...
05-19-2018, 05:28 PM
#3
Permanent S Mode Member
I'm driving an S5 Cabrio and every time I go past a speed-trap meter on the side of the road the speed it shows is always 2-3 MPH slower than what my speedometer shows, meaning that my speedometer is showing my speed as 2-3 miles faster than I'm actually driving. I thought I was imagining things, but tested these same radar traps with other cars and it measured each one exactly the same as the car's speedometer showed. So during my recent maintenance visit at my Audi dealer I told them about this problem assuming that this would be an easy adjustment. To my surprise, the answer that came back was that Audi is aware of this issue, and in fact, it is not an issue since my model is intentionally programmed this way so there is no "fix". I don't know if this applies to all S5 or A5 models, but it surely applies to S5 Cabrios. The good news is that it might save me from a speeding ticket someday, but I still think it is a rather strange setting. Has anybody had the same experience?
1- Your odometer is actually recording 5% more miles than you are driving, negatively affecting your resale value or your lease if you are leasing.
2- From Audi's point of view, they're unwilling to change this as it is boosting your MPG by 5%.
05-19-2018, 05:39 PM
#4
AudiWorld Super User
Speedometers are not a 100% accurate. International rules pretty much stipulate that they can never indicate a speed that's lower than your actual speed, but they are allowed to show up to 110% of your actual speed. The speed is measured based on tire rotations and since the diameter of a tire changes as the tire wears or with varying tire pressure there is no way for a speedometer to be a 100% accurate. On European cars, the speedometers generally show a 5% higher speed than your actual speed. This is perfectly normal and you'll find it to be similar on other cars.
05-19-2018, 09:04 PM
#5
AudiWorld Senior Member
I'm driving an S5 Cabrio and every time I go past a speed-trap meter on the side of the road the speed it shows is always 2-3 MPH slower than what my speedometer shows, meaning that my speedometer is showing my speed as 2-3 miles faster than I'm actually driving. I thought I was imagining things, but tested these same radar traps with other cars and it measured each one exactly the same as the car's speedometer showed. So during my recent maintenance visit at my Audi dealer I told them about this problem assuming that this would be an easy adjustment. To my surprise, the answer that came back was that Audi is aware of this issue, and in fact, it is not an issue since my model is intentionally programmed this way so there is no "fix". I don't know if this applies to all S5 or A5 models, but it surely applies to S5 Cabrios. The good news is that it might save me from a speeding ticket someday, but I still think it is a rather strange setting. Has anybody had the same experience?
05-20-2018, 02:13 AM
#6
A more accurate measurement is to compare speed displayed to Speed indicated by a GPS app like Waze. All of my Audis have been within 1 mph when checked this way. A Porsche Cayman I had on the other hand was off by at least 3%. Discussions on Porsche owners forums indicated that this was intentional on Porsche’s part and that they all were this way and read faster than actual.
05-20-2018, 03:22 AM
#7
AudiWorld Senior Member
You might be able to adjust this using ODB11. I don't remember where exactly I saw it, but I thought there was a setting somewhere that allowed a correction factor to be entered for the speedometer reading.
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05-20-2018, 08:04 AM
#8
Speedometers are not a 100% accurate. International rules pretty much stipulate that they can never indicate a speed that's lower than your actual speed, but they are allowed to show up to 110% of your actual speed. The speed is measured based on tire rotations and since the diameter of a tire changes as the tire wears or with varying tire pressure there is no way for a speedometer to be a 100% accurate. On European cars, the speedometers generally show a 5% higher speed than your actual speed. This is perfectly normal and you'll find it to be similar on other cars.
05-20-2018, 10:21 AM
#9
AudiWorld Senior Member
It all depends on how good they are calibrated. traffic sign speed radar are fairly loose as they are just there to warn you of your speed so it not surprising that they are off by up to 10%.. That said, the couple we have around here matches dead on with my car speed.