Speedometer reads fast

thedude

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I’m seeing a consistent 2mph over indication in my Supra.

Waze agrees with the “your speed is xx” signs which are 2mph lower than the car.

This accelerates depreciation and also causes warranty and service windows to close faster than they should. I believe there have been class actions about this sort of thing in the past.

Anyone else have a fast speedometer?
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A70TTR

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I honestly don't own a single vehicle where the speedo doesn't read a bit faster than I'm actually traveling; it's generally 2-3mph over at highway speeds

what other vehicles have you owned where this is not the case?



EDIT: I just asked a few people around me and all said this is completely normal behavior (which has always been my impression).
 
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thedude

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I honestly don't own a single vehicle where the speedo doesn't read a bit faster than I'm actually traveling; it's generally 2-3mph over at highway speeds

what other vehicles have you owned where this is not the case?



EDIT: I just asked a few people around me and all said this is completely normal behavior (which has always been my impression).
My last car (Audi S4) was pretty spot on.
 

Illsic_Design

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This is spot on for being a BMW. They are known to be like 1-2% off, as I beleive in Germany the automaker can be fined if the speedo reads lower than the car is going. On my 335i this can be changed with coding, not sure on the newer cars. I actually prefer it this way since when my speedo says I'm going 80 or so I'm actually going a little under 80 and usually CHP won't bat an eye for under 80, so helps me with speeding tickets.
 

s219

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I’m seeing a consistent 2mph over indication in my Supra.

Waze agrees with the “your speed is xx” signs which are 2mph lower than the car.

This accelerates depreciation and also causes warranty and service windows to close faster than they should. I believe there have been class actions about this sort of thing in the past.

Anyone else have a fast speedometer?

+2mph is the standard for BMW speedos. How the heck would this have anything to do with depreciation? It doesn't affect the odometer, just the speed displayed to the driver.
 

084runnerltd

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All BMWs read 2-3mph fast...
 
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thedude

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+2mph is the standard for BMW speedos. How the heck would this have anything to do with depreciation? It doesn't affect the odometer, just the speed displayed to the driver.
Can’t say if it does or doesn’t affect the odometer. In more traditional analog odometers, higher speed certainly does impact it and runs up mileage faster.

I’d wonder why, if they can make the odometer correctly indicate the distance traveled, they’re unable to make the speedometer display accurate velocity. Unless over-indicating speed was by choice, why not use the telemetry used by the odometer?
 

Illsic_Design

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Can’t say if it does or doesn’t affect the odometer. In more traditional analog odometers, higher speed certainly does impact it and runs up mileage faster.

I’d wonder why, if they can make the odometer correctly indicate the distance traveled, they’re unable to make the speedometer display accurate velocity. Unless over-indicating speed was by choice, why not use the telemetry used by the odometer?
as I (and others) stated above, it is because in Germany the speedo CANNOT read slower than the speed you are going, EVER, so they play it safe by making it read fast. All manufacturers do this, some to a lesser or greater extent.

See the article for clarity; https://www.thrillist.com/cars/your...accuracy-in-german-american-and-japanese-cars
 

s219

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Can’t say if it does or doesn’t affect the odometer. In more traditional analog odometers, higher speed certainly does impact it and runs up mileage faster.

I’d wonder why, if they can make the odometer correctly indicate the distance traveled, they’re unable to make the speedometer display accurate velocity. Unless over-indicating speed was by choice, why not use the telemetry used by the odometer?
It doesn't affect the odometer and you can prove this to yourself very easily if you don't believe me and all the prior BMW experience.

The speedometer offset is not an error or due to difficulty measuring speed, it's an intentional software tweak to make it read high to the driver. As mentioned, it's done for legal reasons. If you code the car, you can actually change the artificial offset or zero it out.

Both the speedometer and odometer are reading from the transmission, but unlike old mechanical systems that ran a cable up to the dash, it's a sender that converts to an electrical signal and then it goes on to the central computer via wire.
 
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thedude

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It doesn't affect the odometer and you can prove this to yourself very easily if you don't believe me and all the prior BMW experience.

The speedometer offset is not an error or due to difficulty measuring speed, it's an intentional software tweak to make it read high to the driver. As mentioned, it's done for legal reasons. If you code the car, you can actually change the artificial offset or zero it out.

Both the speedometer and odometer are reading from the transmission, but unlike old mechanical systems that ran a cable up to the dash, it's a sender that converts to an electrical signal and then it goes on to the central computer via wire.
Yeah I understand that it’s reading telemetry. Just odd that they would choose not to indicate the actual speed. I haven’t researched it so I’m not mistrusting the collective experience, I’m simply not familiar with it. Thanks for the lesson.
 

zamiel

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I just got my Supra last weekend and noticed this for the first time yesterday when comparing Waze to the speedometer. I've never noticed more than a 1 mph discrepancy on any of the Japanese cars I've owned. I figured there had to be a way to calibrate the speedometer, but it sounds like this is the norm based on this thread. I also came across this BMW thread that seems to confirm that this is normal: https://f87.bimmerpost.com/forums/showthread.php?t=1448247
 

Famo

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Bumping this. Does anyone know if you can code this in bimmercode under the "display options for the instrument cluster." Either the digital speed correction option or the "digital speed in board computer. Would appreciate if anyone can help. Thanks.
 

Kiwi Greg

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I have noticed this for quite a few years & vehicles over here, usually 5-8 kph under right from the get go all through the range

Quite frustrating, what's wrong with showing the accurate speed in a brand new off the lot factory car ?

I guess its a win for the Govt because everyone is going slower than they think & a win for the manufacturer as the car appears to go faster that it actually does

My Supra indicates 2.5kph fast with 285/30 x 20 tyres
 

Famo

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I have noticed this for quite a few years & vehicles over here, usually 5-8 kph under right from the get go all through the range

Quite frustrating, what's wrong with showing the accurate speed in a brand new off the lot factory car ?

I guess its a win for the Govt because everyone is going slower than they think & a win for the manufacturer as the car appears to go faster that it actually does

My Supra indicates 2.5kph fast with 285/30 x 20 tyres
I agree, but im pretty sure with one of the options I mentioned in coding with bimmercode it can be coded to the show the actual speed you are going not the fast one it shows. Just not sure which one exactly is it, guess I'll have to experiment.
 
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