Speedometer Calibration

[redwoody]

hey guys, I just found out my speedo is off. At 80mph per the speedometer, I am actually only going 76 mph. that's 5% off! how can it be recalibrated? can someone other than the stealer do it? thanks.

[MidwestOffroad]

A dealer can reflas it for up to 35 inch tires but it will cost you a hour of shop rate.

Superlift truspeed runs 175-200 bucks and installs in a hour or so. and can be calibrated for 2 tire sizes.

otherwise bullydog has a calibrator and some performance tuners have the option as well

[bigcountrysg]

Originally Posted by redwoody

hey guys, I just found out my speedo is off. At 80mph per the speedometer, I am actually only going 76 mph. that's 5% off! how can it be recalibrated? can someone other than the stealer do it? thanks.

I wouldn't worry about it to much unless. But like Midwest said you can buy a recaliber from SuperLift, you can have a dealer reflash the computer for you, or you can find another programmer that can recalibrate your speedo for you. But for the cost I wouldn't worry about it too much. Mine is off as well ever since I bought the truck and replaced the tires from the stock 265x75R16 to 285x75R16.

[MidwestOffroad]

the main consern with the speedo being off is the engine timing is ran off rpms and the abs sensors and shift points are also controled off the speedo (vss sensor)

[bigcountrysg]

Originally Posted by MidwestOffroad

the main consern with the speedo being off is the engine timing is ran off rpms and the abs sensors and shift points are also controled off the speedo (vss sensor)

I understand that but to be 4 mph off is not that bad. It also is not enough to cause concern. You figure in over time parts wear and there is a bit of play as for what is with in specs of the manufacturer. That is all I am saying. Now if it was 10 or more off then to me that would be needing recalibrated.

[06TWO50Diesel]

Mine's the other way around. 40 is 45... so any highway driving and police lights and I get that sick feeling in my stomach. But really, I could honestly answer,"no officer- I didn't know how fast I was going." haha When my speedo says 80, I'm going 92 I think i'm going the be picking up the Tru-Speed soon.


-nate

[redwoody]

Originally Posted by bigcountrysg

I wouldn't worry about it to much unless. But like Midwest said you can buy a recaliber from SuperLift, you can have a dealer reflash the computer for you, or you can find another programmer that can recalibrate your speedo for you. But for the cost I wouldn't worry about it too much. Mine is off as well ever since I bought the truck and replaced the tires from the stock 265x75R16 to 285x75R16.

yeah, but the crazy thing is that my tires are stock (265 75R16). you can see my mods below. thanks for the help guys. I will discuss with a mechanic although I don't even know one since I don't really ever need one (I own a 7.3 PSD Ford!)

[Mikes7.3]

Silly ? but how did you find out it was off?

[redwoody]

Originally Posted by Mikes7.3

Silly ? but how did you find out it was off?

we used 2 different GPS recievers. both showed 76mph when the speedo showed 80mph. right at about 5% off. also meaning, when I thought I was getting 19mpg, I was only getting 18mpg on my trip....

[bigcountrysg]

How do you know that the gps is correct. Maybe the gps systems are off.