Computer corrects tire size on '05 Tacomas??

[Rock Slide]

My friend bought an '05 Tacoma 4WD a few months ago. He just ordered his lift kit and new 33's. I informed him his speedometer would be off and he'd feel a loss of power unless he upgraded his gears. He then informs me he is aware of the power loss, but that a reliable source told him the new Tacomas can recognize larger tires and the computer will correct the speedometer after about 1200 miles of use. Is this correct, or is someone pulling my friends leg?? I've never heard of a computer correcting the speedometer based on the size tire. I thought you had to buy something extra for that.

 

[sharp4runr]

How does the computer know what size tire was installed? Must be magic gnomes working in the ECU...

 

[07runner]

They are pulling both legs and an arm. If the cars speedometer is calibrated using a specific tire size, then altering that size will cause a error. The computer is not going to magically fix speedometer error due to a tire size change. They are not that advanced, however the 2006 navigation system in the 4runner has a special calibration for when you get new tires. It must be done manually and it is to sink up the gps system to the larger diamater of the new tire tread. However you still need to stay with the stock size tire.

 

[Koz]

They are pulling both legs and an arm. If the cars speedometer is calibrated using a specific tire size, then altering that size will cause a error. The computer is not going to magically fix speedometer error due to a tire size change. They are not that advanced, however the 2006 navigation system in the 4runner has a special calibration for when you get new tires. It must be done manually and it is to sink up the gps system to the larger diamater of the new tire tread. However you still need to stay with the stock size tire.

I think what someone is confusing is the ECU

 

[saaggie]

I know on the old Explorers the dealer could reprogram the ECU with the dimensions of the new tire and the truck would accept it to correct the speedo. My dealer on the 4runner says the ECU allows for up to 3 mph adjustment if you go to bigger tires, I call BS!

 

[Rock Slide]

Well, good I'm glad to hear I was right. Cannot wait to see him again so I can make fun of him! haha

 

[boston_kevin]

So when the cop pulls him over for speeding, he can say that his speedo is being automatically recalibrated for the next 1200 miles? Nope, no such thing unless you have an advanced ECU with GPS and tire position sensors that can check each tire rotation... I think the office may suggest to your friend that his speedo has been calibrated a little too tightly... Maybe boxers would be better