Speedo is off!!

So I have had my Taco for almost 2 months and I noticed when on the highway at 75 people are flying by me like I'm standing still. I have a GPS and my phone has GPS as well, I check the speed and they both tell me at 75, I'm really doing about 70. Just to make sure, I tested both of them in the wife's Santa Fe that we bought new and the speedo matches both GPS readings. How could this be and is it common?

Is it possible the tires are wrong? I have an 06 2.7 AC 6 lug silver steel wheels and the tire size is 245/75/16.

Help before I take it to the stealer to get raped!!

 

don't really know if this is normal or not, but if it helps, my truck is the same way. My GPS is about 5 mph slower than what the spedo says. I just set my cruise up 5 mph faster to compensate. I have noticed that it don't really get that far off until I get to around 55 mph. Under that seems to be pretty close to the GPS.

 

no way

 

What about the odometer? Doesn't the odometer roll at the speed of the speedo? Does that mean the miles are going to be higher then they really are, and end up making the vehicle depreciate that much faster?

 

Mine was off by about 3 mph at 60 or so. 265-70 x 17s fixe that according to the GPS. I think the gas mileage is about the same, as I never corrected for the previous error. But now I am at 19.5-19.8, so every tank I try to drive more like a little old lady to see if I can break 20.

 

All manufacturers do that with the speedo.

 

Mine was off, my 265/70/17s fixed that, according to my Garmin.

 

This topic has already been covered quite thoroughly... do a search.