Speedometer, Off?

[freeheelbille]

I have noticed since day one that the speedometer appears to be off about 2 miles per hour. My radar detector (GPS-enabled), and while using Waze or other map services, always shows 2 mhp faster than the MHP on the dash. This appears more pronounced at highway speed on slower surface streets. Anyone else notice this?

 

[Aero]

Cruise control speedometer vs Google maps speedometer don’t match so which is correct?

Anyone encounter this when they are on cruise control? (I have only used it twice as I like to drive the manual, but was cruising in touring trying to get my mpg to 20 mpg and failed 🤣) The dash speedometer shows one speed while google maps shows usually 2 to 4 mph less. Depends on speed...

www.emiraforum.com

Definitely a few MPH over indicated vs actual.

 

[freeheelbille]

Cruise control speedometer vs Google maps speedometer don’t match so which is correct?

Anyone encounter this when they are on cruise control? (I have only used it twice as I like to drive the manual, but was cruising in touring trying to get my mpg to 20 mpg and failed 🤣) The dash speedometer shows one speed while google maps shows usually 2 to 4 mph less. Depends on speed...

www.emiraforum.com

Definitely a few MPH over indicated vs actual.

Interesting...so we are not clocking miles accurately either?

 

[geoffbland]

I've noticed that the speedometer measures higher than satellite or radar speed in every car I've every had - apart from the Emira. My Emira seems to measure about the same as my satnav and the same as a nearby radar speed sensor that I pass often; "30MPH Thank You For Driving Carefully"

 

[Orchardbike]

I've noticed that the speedometer measures higher than satellite or radar speed in every car I've every had - apart from the Emira. My Emira seems to measure about the same as my satnav and the same as a nearby radar speed sensor that I pass often; "30MPH Thank You For Driving Carefully"

I need to check my Emira, but as you said, every car I’ve ever had, has read higher than actual.

 

[allenyao09]

In my experience the speedometer is pretty accurate, difference only up to 1 mph compared to the GPS speed at cruising.

 

[ManOfSteel]

My Emira reads 1-2 mph higher than GPS speed per Wayz and my radar detector.

 

[Reesebobby]

I also show google to be exactly 2 mph slower than the car says. Do we have to account for the curvature of the earth or something for the gps?

 

[Reesebobby]

I guess this is how they do 0-60 readings…. More like 0-58

 

[MiamiBlue]

I also checked and get the same. Reads 2mph high at 60mph.
Fairy typical I would say. Some cars over read slightly more. Not seen any under read or even be spot on.
I think this is 100% normal.

 

[KJD]

It’s to account for tyre wear iirc.

A tyre with typical 8mm tread will have about 2.5% less circumference when it’s bald than when it’s new.
So it will be spinning faster at any given real (gps) speed and the car’s speedo will read higher.