Speedometer Issue

[MCMfan92]

So first off, i now work for a used car dealership.

Secondly, and most importantly, I took our used 2015 Mirage with 62k on the clock out to grab lunch today (it's on the lot for sale), and I realized that my MPG wasn't where mine is in my hatch (the 2015 is a CVT and so is my 2019, I expected comparable results), so I pulled up a GPS speedometer and while the in-car speedo showed 25, the GPS showed 35.

Tires and wheels are aftermarket, and tire size was 185/55r15. Stock is 165/65r14, as we all know.

I plugged these into a comparison calculator, its a 2.5% difference as far as speedometer reading.

I'm super curious as to why it's 10mph off, that's way more than 2.5%.

Just wondering if this is anything I can look into before it goes to Mitsubishi for service.

Thanks a ton guys. Hope ya'll have been okay

[Eggman]

Sounds like that Mirage had its ETACS tampered with.

[Fummins]

Weird. All our work cars(2015-2019) and I'm pretty sure my one 2014 speedo read 5kph faster than gps apps.

[Mark]

So first off, i now work for a used car dealership.

Secondly, and most importantly, I took our used 2015 Mirage with 62k on the clock out to grab lunch today (it's on the lot for sale), and I realized that my MPG wasn't where mine is in my hatch (the 2015 is a CVT and so is my 2019, I expected comparable results), so I pulled up a GPS speedometer and while the in-car speedo showed 25, the GPS showed 35.

Tires and wheels are aftermarket, and tire size was 185/55r15. Stock is 165/65r14, as we all know.

I plugged these into a comparison calculator, its a 2.5% difference as far as speedometer reading.

I'm super curious as to why it's 10mph off, that's way more than 2.5%.

Just wondering if this is anything I can look into before it goes to Mitsubishi for service.

Thanks a ton guys. Hope ya'll have been okay

I go past a speed limit sign that has a radar sensor that clocks/shows your speed when entering town every day. If I went by that reading, I feel like my Mirage with 165/65r14 tires is going slightly slower than the speedometer reading.

I always felt 175/65r14 (23") & 185/55r15 (23") tires may be closer to the actual speed than the 165/65r14 (22.4") or 175/55r15 (22.6") factory tires.

[MCMfan92]

That's all interesting information to know

I'll have them check ETACS.