Speedometer vs. Odometer

I noticed that my speedometer was a few percent off according to my GPS (Speedo- 75, GPS- 72). The first thing I thought was that the dealer calibrated my truck so that it would register more miles than I was traveling and my warranty would run out faster. But I checked the odometer against my GPS odometer and it was DEAD on (Odo- 100, GPS- 99.9). Anybody else notice this? What's the deal? Is my GPS or my Speedometer/Odometer off? Not really a big concern, in fact, it helps me out as I plan on increasing tire size which should straighten out the speedometer issue. Just curious if y'all have the same thing.

 

All speedometers are like that. They only calibrate it to within a certain % from the factory, usually reading a little faster than actual speed.

 

exactly what i wanted to know. gracias

 

I read something about your tires affecting your speedometer accuracy.

 

i noticed the same thing with my truck and GPS

 

Well, yes ... Change the overall diameter of your tire and you'll throw off the speedometer readings.

 

My speedometer needle on the dash is off by 2mph.

I have a scangauge and the MPH it pulls from the ECU - is dead on with the GPS.

Soooo...that's telling me that the needle on the speedometer isn't calibrated properly to the numbers. No biggie.... as long as the computer is accurate, who cares about the needle.

 

It is another of those penny saving acceptable margins of error in manufacturing tolerance. Pretty much all manufacturers speedos are slightly off so that they read slightly faster then you are actually going, but never slower. I have seen reports that they can be off by as much as 6% or more depending on the vehicle. I don't know what Toyota's allowable tolerances are but everyone can expect to be slightly off.

Even on stock size tires as they wear down the speedo will read faster. Larger then stock tires will cause the speedo to register slower then you are actually going.

 

Good info to have!

 

Setting the Scangauge to read MPH, it is dead on with the GPS. The speedo gauge itself is what's off.

 

My previous vehicles were always dead on with GPS but yea my Taco is off by around 3 or so. Shows I'm going faster than I am going.

 

my gps is a little faster than the all thevehicles i've driven it in.
f250, accord, colorado, dakota, tacoma, camry