XE ( X760 ) 2015 -

Speedometer Problem

Old Mar 27, 2017 | 03:46 PM
  #41  
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Originally Posted by myjag1
I have this same issue. 35t AWD with the 20 Rims.

I took the car on a road trip and I had the cruise set at 80 mph in a 70 mph speed zone and there was still cars flying past me. I wonder if this is an issue with the 20 rims?

I am leasing and I am also worried about the milage racking up quicker than it should.
That's called driving in Vegas last time I looked.

As for the over-reading thing, I've only had one car that under-read (speed and distance), and that was because it had 75 profile tyres fitted instead of the stock 70 series. None of my cars have ever been spot on and I think a Volvo S60 was the worst for over-reading.

For those of you relying on GPS, what's the likely +/- error with those apps? I'm a measurement engineer, so I have a healthy skepticism about devices that claim to be super accurate, and GPS is just one of them.

I wonder if the mile markers at the roadside are placed per GPS or some other surveying method. Timing them accurately I would tend to believe a bit more over some Dumbphone app.
 

Last edited by agentorange; Mar 27, 2017 at 03:58 PM.
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Old Mar 28, 2017 | 01:19 AM
  #42  
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Some dealers are a bit useless at knowing they can (*) set things in the car (such as the tyre details).

Commonly the speed over-reads on the dash as per Mikey's wiki link but the OBD will give the data the car actually uses. It will calculate miles based on that, not on the over-read value. (Test over more than 1 mile!)

It should be obvious that fitting non-OE-size rims etc will affect the values if you don't reprogram the car. And again obviously and as has been posted, as tyres wear the size varies (as it does with tyre pressure).

(*) well, should be able to
 

Last edited by JagV8; Mar 28, 2017 at 01:22 AM.
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Old Mar 28, 2017 | 11:48 AM
  #43  
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I'll just leave this here...

http://media.caranddriver.com/ez/original/application/1e1b33f85f31df61e4830f32f82a5a71.pdf
 
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Old Oct 12, 2017 | 09:23 AM
  #44  
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New owner, also getting a speedo being high about 4mph at highway speeds.

Has anyone confirmed the ODO is tracking high or accurate vs with the Speedo being high?

Since I have a lease this is concerning to think of all the extra miles being put on the vehicle that I am not getting to actually drive.
 
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